NOVEL THERAPEUTIC AGENTS THAT MODULATE NEUROKININ RECEPTORS

Abstract: Novel multi-binding compounds (agents) which bind neurokinin receptors are used to treat disorders in mammals that are mediated by the neurokinin receptors, such as Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthritis, cystitis, osteoarthritis, irritable bowel syndrome, allergic rhinitis, pain, chronic pain, migraine headaches, asthma, bronchitis and chemotherapy induced emesis. The compounds of this invention comprise a plurality of ligands each of which can bind to such receptors thereby modulating the biological processes/functions thereof. Each of the ligands is covalently attached to a linker or linkers which may be the same or different to provide for the multi-binding compound. The linker is selected such that the multi-binding compound so constructed demonstrates increased modulation of the biological processes mediated by the neurokinin receptor. The invention is also directed to pharmaceutical compositions comprising the multi-binding compounds, methods of inhibiting and treating the disorders mediated by neurokinin receptors, and methods of preparing multi-binding compounds of the invention.

Description: NOVEL THERAPEUTIC AGENTS THAT MODULATE NEUROKININ RECEPTORS CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 60/088,466 filed on June 8, 1998 and U.S. Provisional Application No. 60/092,938 filed on July 15, 1998, both of which are incorporated by reference herein in their entirety. BACKGROUND OF THE INVENTION Field of the Invention This invention relates to novel therapeutic agents that bind to mammalian receptors and modulate their activity. More particularly, the invention relates to novel therapeutic agents that bind to and modulate the in vivo activity of neurokinin receptors in mammals by acting as multi-binding compounds. The therapeutic agents or multi-binding compounds described herein comprise at least two ligands connected by a linker or linkers, wherein said ligands in their monovalent state bind to and/or are capable of modulating the activity of the neurokinin receptors. The linking moiety is chosen such that the multi-binding compounds so constructed demonstrate increased biological activity as compared to individual units of the ligand. The invention also relates to methods of using such compounds and to methods of preparing such compounds. These multi-binding compounds are particularly useful in treating mammalian conditions that are mediated by the neurokinin receptors targeted by the ligands, such as Parkinson's disease, Alzheimer's disease, depression, anxiety, pain, chronic pain, migraine headaches, rheumatoid arthritis, irritable bowel syndrome, osteoarthritis, cystitis, allergic rhinitis, asthma, bronchitis and emesis, which are mediated by at least the NK, receptor. Accordingly, this invention also relates to pharmaceutical •compositions comprising a pharmaceutically acceptable excipient and an effective amount of a multi-binding compound of this invention. References The following publications may be cited in this application as superscript numbers: 1. J. March, Advanced Organic Chemistry, 4 th Edition, Wiley- Interscience New York (1992). 2. Remington's Pharmaceutical Sciences, Mace Publishing Company, Philadelphia, PA, 17th ed. (1985). 3. Green, Protective Groups in Organic Synthesis, 2 nd Edition, John Wiley & Sons, New York, New York (1991). 4. Gregory, R. E. et al, "5-HT 3 Receptor Antagonists for the Prevention of Chemotherapy-Induced Nausea and Vomiting". Drugs (1998) 55(2): 173-189. 5. Khawaja, A. M., Rogers, D. F., "Tachykinins: receptor to effector", Int. J. Boichem. Cell Biol Vol. 28, No. 7, pp. 721-738, 1996. 6. Swain, C. J., "2 Neurokinin Receptor Antagonists", Progress in Medicine Chemistry, Vol. 35, pp. 57-81, 1998. 7. Gralla, R.J. "Anti-emesis with Cancer Chemotherapy", Europ. J. of Cancer (1997) 22(4):S63-S67. 8. Cunningham, R.S., "5-HT 3 -Receptor Antagonists: A Review of Pharmacology and Clinical Efficacy", Oncology Nursing Forum, (1997) 24(7, supp.):33-39. 9. Mills, S. G., "Chapter 6. Recent Advances In Neurokinin Receptor Antagonist", Annual Reports In Medicinal Chemistry, Vol. 32, pp. 51-60, 1997. 10. Kramer, M. S., et al., "Distinct Mechanism For Antidepressant Activity by Blockade of Central Substance P Receptors", Science, Vol. 281, pp. 1640-1645, Sept. 1998. 11. Kucharczyk, N., "Section Review, Central & Peripheral Nervous Systems, Tachykinin antagonists in development", Exp. Opin. Invest. Drugs (1995) 4(4):299-311. 12. Rupniak, N. M. J., Williams, A. R., "Differential inhibition of foot tapping and chromodacryorrhoea in gerbils by CNS penetrant and non-penetrant tachykinin NK, receptor antagonists", European Journal of Pharmacology 265 (1994) 179-183. 13. Rupniak, N. M. J., et al., "In vitro and in vivo predictors of the anti- emetic activity of tachykinin NK, receptor antagonists", European Journal of Pharmacology 326 (1997) 201-209. 14. Takeuchi, Y., et al., "Derivation of a Three-Dimensional Pharmacophore Model of Substance P Antagonists Bound to the Neurolinin-1 Receptor" J Med. Chem., 1998, 41, 3609-3623. 15. Swain, C. J., "Patent Update, Central & Peripheral Nervous Systems, Neurokinin receptor antagonists", Exp. Opin., Ther. Patents (1996) 6(4):367-378. 16. "Distress vocalization in rat pups", Chapter E Psychotropic and neurotropic activity, E.2.4.8, pp. 236-237. 17. Cascieri, M. A„ et al., "Characterization of the binding and activity of a high affinity, pseudoirreversible morpholino tachykinin NK, receptor antagonist", European Journal of Pharmacology 325 (1997) 253-261. 18. Elliott, J. M., et al., "Serine Derived NK1 Antagonists 1 : The Effects Of Modifications to the Serine Substituents", Bioorganic & Medicinal Chemistry Letters 8 (1998) 1845-1850. 19. Hale, j. j., et al., "Structural Optimization Affording 2-(R)-(l-(R)- 3,5-Bis(trifluoromethyl)phenylethoxy)-3-(S)-(4-fluoro)phenyl-4-(3- oxo-l,2,4-triazol-5-yl)methylmorpholine, a Potent, Orally Active, Long- Acting Morpholine Acetal Human NK-1 Receptor Antagonist", J. Med. Chem. 1998, 41, 4607-4614. 20. Hale, j. j., et al, "2(S)-((3,5-Bis(trifluoromethyl)benzyl)-oxy)-3- (S)-phenyl-4-((3-oxo-l,2,4-triazol-5-yl)methylmorpholine (l): a Potent, Orally Active, Long- Acting Morpholine-Based Human Neurokinin-1 Receptor Antagonist", J. Med. Chem. 1996, 39, 1760- 1762. 21. von Sprecher, A., et al., "Neurokinin antagonists as potential therapies for inflammation and rheumatoid arthritis", IDrugs 1998 1(1):73-91. 22. Longmore, j., et al, "Neurokinin Receptors", DN&P 8(1), Feb. 1995, pp. 5-23. 23. Drug Report, copyrighted 1997-1998 Current Drugs Ltd. , last updated 22 Oct. 1998 18 pages. All of the above publications are herein incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference in its entirety. State of the Art A receptor is a biological structure with one or more binding domains that reversibly complexes with one or more ligands, where that complexation has biological consequences. Receptors can exist entirely outside the cell (extracellular receptors), within the cell membrane (but presenting sections of the receptor to the extracellular milieu and cytosol), or entirely within the cell (intracellular receptors). They may also function independently of a cell (e.g., clot formation). Receptors within the cell membrane allow a cell to communicate with the space outside of its boundaries (i.e., signaling) as well as to function in the transport of molecules and ions into and out of the cell. A ligand is a binding partner for a specific receptor or family of receptors. A ligand may be the endogenous ligand for the receptor or alternatively may be a synthetic ligand for the receptor such as a drug, a drug candidate or a pharmacological tool. The super family of seven transmembrane proteins (7-TMs), also called G-protein coupled receptors (GPCRs), represents one of the most significant classes of membrane bound receptors that communicates changes that occur outside of the cell's boundaries to its interior, triggering a cellular response when appropriate. The G-proteins, when activated, affect a wide range of downstream effector systems both positively and negatively (e.g., ion channels, protein kinase cascades, transcription, transmigration of adhesion proteins, and the like). The ligands that bind to G-protein cellular receptors may be specifically classified as follows: 1. Full agonists - ligands that when bound trigger the maximum activity seen by natural ligands; 2. Partial agonists- ligands that when bound trigger sub-maximal activity; 3. Antagonist- ligands that when bound inhibit or prevent the activity arising from a natural ligand binding to the receptor. Antagonists may be of the surmountable class (results in the parallel displacement of the dose-response curve of the agonist to the right in a dose dependent fashion without reducing the maximal response for the agonist) or insurmountable class (results in depression of the maximal response for a given agonist with or without the parallel shift); 4. Inverse antagonist-ligands that when bound decrease the basal activity of the unbound receptor (if any). There are four fundamental measurable properties that pertain to the interaction of a ligand with its receptor including G-protein cellular receptors: 1) the affinity of the ligand for the receptor, which relates to the energetics of the binding; 2) the efficacy of the ligand for the receptor, which relates to the functional downstream activity of the ligand; 3) the kinetics of the ligand for the receptor, which defines the onset of action and the duration of action; and 4) the desensitization of the receptor for the ligand. With regard to the ligand, it is the combination of these properties that provides the foundation for defining the nature of the functional response. Thus, an activating ligand (or agonist) has affinity for the receptor and downstream efficacy. In contrast, an inhibiting ligand (antagonist) has affinity for the receptor but no efficacy. Selectivity defines the ratios of affinities or the ratios of efficacies of a given ligand compared across two receptors. It is the selectivity of a specific drug that provides the required biological profile. For example, in certain therapeutic settings, it is currently thought that a highly selective drug may be preferred (e.g., Losartan (Cozaar), an antihypertensive, is a highly selective antagonist for the ATI receptor). In contrast, it considered that a drug with a broad spectrum of receptor activity may be preferred in other therapeutic settings. Current drugs (ligands) targeting receptors, including G-protein receptors, have clinical shortcomings identified by one or more of low efficacy, low affinity, poor safety profile, lack of selectivity or overselectivity for the intended receptor, and suboptimal duration of action and onset of action. Accordingly, it would be beneficial to develop ligands that have improved affinity, efficacy, selectivity, onset of action and duration of action. Affinity of ligand for target receptor An increase in ligand affinity to the target receptor may contribute to reducing the dose of ligand required to induce the desired therapeutic effect. A reduction in ligand affinity will remove activity and may contribute to the selectivity profile for a ligand. Efficacy of ligand at a target receptor (functional effect) An increased ligand efficacy at a target receptor can lead to a reduction in the dose required to mediate the desired therapeutic effect. This increase in efficacy may arise from an improved positive functional response of the ligand or a change from a partial to full agonist profile. Reduced efficacy of a full agonist to a partial agonist may provide clinical benefit by modulating the biological response. Selectivity of ligand compared across receptor subtypes An increase in the selectivity of the ligand across receptor subtypes requires that the affinity or efficacy of the ligand at other receptors is reduced relative to the desired receptor. A decrease in the selectivity of the ligand may also be desired. For example, the angiotensin II endogenous ligand activates both the ATI and AT2 receptor subtypes. However, Losartan is a selective ATI receptor antagonist. More rapid onset of action of the ligand to effect a biological response is often preferred. Duration of Action An increased duration of action of the ligand to effect a biological response may be preferred. For example β 2 adrenergic agonists such as albuterol have a relatively short duration of action of approximately 3-4 hours and an increase in duration of action would simplify the dosing regimen required to administer this drug (ligand). Desensitization of the receptor for the ligand Desensitization is best defined as the variety of processes by which the functional interaction of the receptor with its G-protein are influenced. These processes lead ultimately to a reduction in cellular response to the activating agonist. Such phenomena are most often observed during prolonged stimulation of the receptor. The two main pathways for receptor desensitization are reduction in receptor density or changes in receptor structure by phosphorylation mechanisms. Receptor density is altered by receptor sequestration. This is a reversible process that is observable within minutes and is a dynamic sorting of receptors with receptors being cycled to and from the membrane. On the other hand, receptor down-regulation is generally slower, in the order of hours, and is irreversible, involving destruction of the receptor. Finally, receptor density may be affected by an alteration in the rate of synthesis. For example, the rate of β 2 mRNA synthesis and degradation are controlled by levels of c- AMP within the cell. Alternatively, receptor desensitization may occur through changes in receptor structure, such as receptor phosphorylation. For example, agonist induced activation of the β 2 -adrenergic receptor, which is positively coupled to adenylate cyclase through Gs, results in an elevation in an increase in the levels of c-AMP and an increase in the activity of protein kinase A. This kinase can readily phosphorylate the consensus site in the third intracellular loop. The phosphorylated β 2 -adrenergic receptor exhibits significantly reduced coupling to Gs. Besides PKA, the G-protein coupled receptor kinases (GRK) are also involved in the desensitization of GPCRs. For the β 2 -adrenergic receptor, there are two of these kinases bARKl and bARK2. These GRKs are more specific and will only phosphorylate an agonist activated receptor. Furthermore this GRK desensitization requires an arrestin protein. Receptor oligomerization also plays a role in receptor function. This is best exemplified in the area of growth receptors that are known to act functionally and structurally as dimers, e.g., EGF-R and interferon receptor. It is also known that dimerization is involved in the functioning of the steroid receptor. Preliminary evidence is beginning to appear on the importance of oligomerization in G-protein coupling and signaling. It is proposed that receptor oligomerization may play a role in different receptor functions such as mediating coupling of the G-protein or receptor intemalization. In addition, higher molecular weight species have been observed for a range of GPCRs that includes tachykinin receptors 5 , among others. One important class of GPCRs is the tachykinin receptors including the neurokinin (NK„ NK 2 , and NK 3 ) receptors. NK, receptors are found both in the central nervous tissue and in peripheral organs, such as spinal cord, gastrointestinal tract, urinary bladder, airway epithelium and submucosal glands. NK 2 receptors are found mainly in peripheral organs, including gastrointestinal tract and airway smooth muscle with small amounts in the central nervous system (CNS). NK, receptors are confined mainly to the CNS, primarily the cerebral cortex and dorsal horn of the spinal cord, with some in the urinary and intestinal tracts. 5 The neurokinin receptors were initially characterized by their preferential affinities for the endogenous tachykinin ligands, namely Substance P (SP), Neurokinin A (NKA) and Neurokinin B (NKB). The receptors have potency orders of SP>NKA>NKB at the NK, receptor, NKA>NKB>SP at the NK 2 receptor, and NKB>NKA>SP at the NK 3 receptor. 5 Since the dominant receptor in the CNS is the NK, receptor, SP is the principal tachykinin neurotransmitter in the CNS. NKA is co-localized with SP in most areas in relatively minute quantities. Consequently, the majority of the tachykinin effects relate to the action of SP.^ The tachykinin receptors are coupled to the pertussis-toxin-insensitive G q /G n family, which is linked to the phosphoinositide metabolism. Tachykinins are able to elicit their effects by activating multiple effectors, such as phosphoinositide pholipase C (PLC), via different G-proteins. PLC breakdown produces inositol 1, 4, 5-trisphosphate (IP 3 ) and diacylglycerol (DAG). IP 3 releases calcium from intracellular stores by acting on specific receptors on the sarcoplasmic reticulum. DAG increases intracellular calcium by opening voltage- gated Ca 2 ~ channels via protein kinase C. 3 Substance P and the related tachykinins NKA and NKB are endogenous agonists representing a family of peptides that share a common C-terminal sequence 'Phe-X-Gly-Leu-Met-NH 2 '. They are mainly found in unmyelinated sensory somatic and visceral fibres of neurons, in enteric sensory neurons and in pathways within the brain. 6 They play a critical role in nociception, stress, neurogenic inflammation, smooth muscle contraction, vasolidation and secretion, and immune system activation. 22 Substance P may function as a sensory neurotransmitter or neuromodulator in the pain pathways from unmyelinated C-fibres involved in nociception. 22 Migraine headache pain, for example, has been associated with neurogenic inflammation within the dura mater, a pain-producing intracranial tissue. There is also an indication of a therapeutic opportunity in rheumatoid arthritis, irritable bowel syndrome, cystitis and allergic rhinitis. 22 Substance P may also innervate the brainstem in the region of the nucleus tractus solitarius (NTS), a CNS area involved in the control of emesis. Emesis or vomiting, especially when induced by chemotherapy and radiation, is controlled by the NTS of the brain. Moreover, Substance P is released in the NTS following cardiovascular and respiratory sensory impulses, thereby indicating an important role in the central control of respiration. Tachykinins cause extravasation, vasodilation, bronchoconstriction and mucus secretion. Asthma and chronic bronchitis, for example, have symptoms, such as tissue edema, that are caused in part by extravasation. 22 Further, tachykinins within the CNS may have a role in modulating the activity of norepinephrine, choline and dopamine pathways (the noradrenergic, cholinergic and dopinergic nerves) that are involved in affective disorders and responses to stress. Parkinson's disease, Alzheimer's disease, depression and anxiety are believed to result from neurotransmitter dysfunction in the CNS. 5 ' 6 Antagonists have been developed to prevent the binding of the tachykinin ligands to their respective receptors. The antagonist itself binds to the receptor and thereby either blocks the agonist from binding to that site, or alters the binding site, so that the agonist can not bind to the receptor. If the agonist does not bind to the receptor, the affects of the tachykinin are not expressed and the disease condition is ameliorated. The binding of the antagonist to the receptor prevents transmission of impulses that initiate the symptoms of the disease. There have been numerous studies to determine the binding sites of the agonists, antagonists and G-protein coupling of the neurokinin receptors. It is suggested that the Substance P binding sites are not distinct, but overlap and may involve different residues that are close when visualized in 3 dimensions (3-D). The common carboxy terminals of the tachykinins, which are responsible for their common biological activity, are thought to interact with groups of amino acids on the amino terminal and first extracellular loop of the three receptor subtypes. A group of residues on the third extracellular loop is also required for high affinity binding of the endogenous peptides. Moreover, SP binding has been shown to be affected by substitution of the first transmembrane domain and the amino terminal of the NK, receptor. 5 The binding sites on the NK, receptor for synthetic antagonists have been studied as well in an effort to develop therapeutic drugs for the treatment of diseases in which the neurokinin receptors play a role. Research suggests that the binding sites overlap in a way similar to that of the binding sites for SP. Currently, a variety of neurokinin receptor synthetic antagonists are under test for the treatment of pain, migraine headaches, inflammation, rheumatoid arthritis, irritable bowel syndrome, cystitis, osteoarthritis, allergic rhinitis, asthma, bronchitis, depression, Parkinson's and Alzheimer's diseases, and anxiety and chemotherapy induced emesis, for example. 22 Examples of these antagonists include tryptophan-based lanepitant LY-303870 (Eli Lilly) for migraine, pain and asthma; a tri-peptide FK-888 (Fujisawa) for asthma, bronchitis and migraine; piperidines, such as and L-758298 (Merck); and diamines, such as CP-122721 (Pfizer) for emesis, inflammation, pain, migraine and asthma, and GW-205171 (Glaxo Wellcome) for emesis, migraine, pain and inflammation. 15 None of the synthetic antagonists currently under test have proven to eliminate all of the symptoms of even one of the above disorders in clinical trials in desirable therapeutic amounts, or without side effects, such as effectiveness, delayed onset of action, nausea and sexual dysfunction, for example. Accordingly, novel ligands having desired potency and therapeutic effect for the neurokinin receptors would be particularly desirable in order to eliminate or ameliorate the symptoms associated with Parkinson's disease, Alzheimer's disease, depression, anxiety, irritable bowel syndrome, cystitis, allergic rhinitis, arthritis, other inflammations, pain, migraine headaches, asthma, bronchitis, other airway diseases, or emesis, especially chemotherapy induced emesis, in mammalian patients. Such novel ligands would preferably achieve the desired potency and therapeutic effect by modulating one or more of the ligand' s properties as to efficacy, affinity, safety profile, selectivity, duration of action and/or onset of action. SUMMARY OF THE INVENTION This invention is directed, in part, to novel multi-binding compounds that bind neurokinin receptors and consequently these compounds can be used to treat conditions mediated by neurokinin receptors, i.e., neurological diseases, such as Parkinson's and Alzheimer's, depression and anxiety; inflammation, such as rheumatoid arthritis, osteoarthritis, irritable bowel syndrome, cystitis and allergic rhinitis; pain, such as chronic pain and migraine headaches; respiratory diseases, such as asthma and bronchitis; and emesis, such as chemotherapy induced emesis. Accordingly, in one of its composition aspects, this invention is directed to a multi-binding compound and salts thereof comprising 2 to 10 ligands, which may be the same or different and which are covalently attached to a linker or linkers which may be the same of different, wherein at least one of said ligands comprises a ligand domain capable of binding to a neurokinin receptor. Preferably, at least two, and more preferably, each of the ligands comprises a ligand domain capable of binding to a neurokinin receptor. Most preferably, the ligand comprises a ligand domain capable of binding to the NK, receptor to block Substance P. In another of its composition aspects, this invention provides a multi- binding compound of Formula I: ( ) p (X) q I wherein each L is a ligand that may be the same or different at each occurrence and is independently selected from ligands comprising a ligand domain capable of binding to a neurokinin receptor; X is a linker that may be the same or different at each occurrence; p is an integer of from 2 to 10; q is an integer of from 1 to 20; and pharmaceutically acceptable salts thereof. Preferably, q is less than p. In one embodiment, q is equal to 0, when X comprises a covalent linkage instead of a linker compound. At least one, and preferably each, of the ligands L independently comprises the structure of Formula (A) below and illustrated in Figure 1 A: wherein: Z represents CK 2 B, NEB, NOB, =NB, =O, Oi?, SB, wherein: B represents H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y represents CUB, NB, NR, O, or S; R 1 represents B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen- containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A represents hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, or oxyacylamino; with the proviso that the compound includes one B moiety which is a direct link to the linker. In one embodiment, when the linker is linked to the ligand through a ring nitrogen or through the A or R groups, Z is CH 2 !?, NHB, =NB, OB or SB, then B is alkaryl wherein the alkaryl comprises one or more substitutions on one or both of alkyl- and aryl- portions thereof, the substitutions comprising a R 2 R 3 substituted alkaryl or R 2 R 3 substituted alkyl-R 4 R 5 substituted aryl, wherein: R 2 and R 3 are individually selected from H, alkyl, substituted alkyl, alkylene, substituted alkylene, alkenyl, substituted alkenyl, alkoxy, substituted alkoxy, alkylalkoxy, acyl, acylamino, aminoacyl, acyloxy, carboxyalkyl or oxyacylamino; and R 4 and R 5 are individually selected from CF 3 , OCH , OCF 3 , or a substituted nitrogen-containing heterocyclyl group; In another embodiment, the ligand is a ligand precursor and Z is OH, NOH or NHB, where B is H; Y is either O or CH 2 ; R 1 is H or an amino protecting group; and R is either H or oxo. As described below, ligand precursors may be linked together with a linker prior to completing the ligand synthesis. The preferred ligand L class comprises the structure of Formula (B) below and illustrated in Figure IB: wherein: Z represents CH 2 , NB, NOH, NR, O, or S; B represents aryl, substituted aryl or a direct covalent link to the linker; A represents aryl, substituted aryl or a direct link to the linker; and Y, R and R 1 (and likewise, R 2 and R 3 , which have the same meaning as R 1 ) have the meanings defined above for the embodiments of formula (A). In a preferred embodiment of the preferred ligand class (Formula B), if A is substituted, it is substituted with a halogen or haloalkyl group; and in still another preferred embodiment, the aryl group in B has two substitutions comprising either the same or different ones of the following groups CF 3 , OCH 3 , OCF 3 , or a substituted nitrogen-containing heterocyclyl group, for example, a substituted tetrazole (e.g. a trifluoromethyl tetrazole). Table 2 and Figure 2 illustrate examples of preferred monovalent ligands having the structure of Formulas (A) or (B) which are useful for the invention. The monovalent ligands of Table 2 have particular selectivity for the NK, receptor. In still another of its composition aspects, this invention provides a multibinding compound of formula II: X'— L' II wherein each L' is independently a ligand comprising a ligand domain capable of binding to a neurokinin receptors and X' is a linker; and pharmaceutically-acceptable salts thereof. In the multibinding compound of Formula II, each ligand, L', is a ligand that may be the same or different at each occurrence and is independently selected from ligands comprising a ligand binding domain capable of binding to a neurokinin receptor; X' is a linker; and pharmaceutically-acceptable salts thereof. Each linker (X or X') in the above embodiments is preferably independently selected from a structure of Formula (III): E'-R 6 -E 2 (III) wherein: R 6 is independently an alkyl, substituted alkyl, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenyl, substituted alkenyl, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, aryl, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, or oxyacylamino, for example. E l and E 1 are end groups that are capable of reacting with amino, hydroxy, halo, alkyl, or thiol containing groups on the ligands, or on precursors thereof, to form a linkage. Representative examples of the E 1 and E 2 end groups include, but are not limited to halogen, haloalkyl; carboxyl, carboxyalkyl, carbonyl, acyl, acyloxy, or halo-containing acyl. In one embodiment, the linker (X or X') comprises a covalent linkage and may not have the structure of Formula III above. In accordance with this invention, the multi-binding compounds have the formula of Formula I or II above, wherein p is an integer from 2 to 10, and q is less than/?. The linker(s) can attach to the ligand(s) L or the ligand precursor in at least three different ways to provide multi-binding compounds of the invention with ligand binding domains for the neurokinin receptor sites. The three preferred ligand-to-linker attachments involve the nitrogen (N4), the carbon (C2), or the carbon (C3) locations of the N-containing heterocyclic (piperidinyl or morpholinyl) group. The linkages between linker and ligand (L)p(X)q are preferably selected from: (a) N4 Linkage N-R 6 -N (la) wherein N represents N4 on the nitrogen containing heterocyclic (piperidinyl or morpholinyl) group of the ligand; and R 6 is a part of the linker as defined above; (b) C2 Linkage Z-R 6 -Z (lb) wherein Z is the group attached to C2 on the N-containing heterocyclic (piperidinyl or morpholinyl) group and has the definition as provided above for Formulas (A) and (B) and R 6 is a part of the linker as defined above; and (c) C3 Linkage A-R 6 -A (lc) wherein A is the group attached to C3 of the N-containing heterocyclic (piperidinyl or morpholinyl) group and has the definition provided above for Formulas (A) and (B) above, and R 6 may or may not be a part of the linkage as defined above, depending on whether X is a linker or a covalent linkage. In presently preferred embodiments, each linkage type la, lb, lc may be found in multi-binding compounds of the present invention using any of the preferred ligand compounds illustrated in Figure 2 and listed in detail in Table 2 (such as LY-754-030/MK869, LY-754-030, LY-742-694, LY-742-311, LY-733- 060, GW-205171 and CP-122721) or using ligand precursor compounds. However, it is not the intent of the inventors to be limited to multi-binding compounds having one or more of the three linkage types described above. There may be other linkers X and linkages between the ligands and the linkers defined above, which would be within the scope of the present invention. For example, it is within the scope of the invention that ligands of formula (A) or (B) may be linked at the C5 or C6 location of the N-containing heterocyclic (piperidinyl or moφholinyl) group. Further, it is within the scope of the invention that the ligands may be linked between the R 1 groups on N4 of the N-containing heterocyclic (piperidinyl or moφholinyl) group. Still further, it is within the scope of the invention that the linkage may be between B groups on C2, or between the A groups between C3, of the N-containing heterocyclic (piperidinyl or moφholinyl) group. As long as the multi-binding compound has the Formula (I), (L)p(X)q, the multi-binding compound is within the scope of the invention. Preferred multi-binding compounds of this invention include by way of example compounds illustrated in Figure 3 (Preferred Embodiments). In another of its composition aspects, this invention is directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier or excipient and a therapeutically effective amount of one or more multi-binding compounds comprising from 2 to 10 ligands covalently attached to one or more linkers wherein each of said ligands independently comprises a ligand binding domain for the neurokinin receptors; and pharmaceutically-acceptable salts thereof, preferably represented by Formula I or II; wherein each ligand is covalently attached to the linker and comprises a ligand domain capable of binding to a neurokinin receptor; thereby inhibiting the action of tachykinin agonists, such as Substance P, NKA and NKB at the neurokinin receptors and modulating the diseases and conditions resulting therefrom. In particular, such compositions are useful for modulating Parkinson's and Alzheimer's diseases, depression, anxiety, inflammation, rheumatoid arthritis, pain, migraine headaches, asthma, bronchitis, irritable bowel syndrome, allergic rhinitis, osteoarthritis, cystitis, and emesis, preferably chemotherapy induced emesis, in mammals. Preferably, the pharmaceutical compositions of this invention comprise ligands L or L' having the structure of Formula (A) or (B) and linkers X or X' having the structure of Formula (III) and q is less than/.. More preferably, said ligands of the multi-binding compounds are selected from the group consisting of MK-869/LY-754-030, LY-754-030, LY-742-694, LY-742-31 1, LY-733-060, GW- 205171 and CP- 122721, or the ligand precursors, as illustrated in Table 2. Most preferably, such compositions comprise multi-binding compounds having any of the ligand-to-linker attachments of the types la, lb, lc above. In another most preferred embodiment, the ligands have a ligand domain capable of selectively binding to the NK, receptor. In still another embodiment, q is equal to zero, and X or X' does not have the structure of Formula III. Instead X is a covalent linkage that does not become a part of the pharmaceutical composition. In one of its method aspects, this invention is directed to a method of preparing a multi-binding compound represented by Formula I: ( ) p (X) q I wherein: each L is a ligand that may be the same or different at each occurrence; each X is a linker that may be the same or different at each occurrence; p is an integer of from 2 to 10; and q is an integer of from 1 to 20; wherein each ligand is covalently attached to the linker and comprises a ligand domain capable of binding to a neurokinin receptor; the method comprising: (a) providing at least , equivalents of a ligand L or precursors thereof and at least q equivalents of linker or linkers X; and (b) covalently attaching said ligands to said linkers to produce a multi-binding compound; or (b') covalently attaching said ligand precursors to said linkers and completing the synthesis of said ligands thereupon, thereby to produce a multi-binding compound. Preferably, the ligands L have the structure of Formula (A) or (B) and the linkers X have the structure of Formula (III) and q is less than/.. In another embodiment, X comprises a covalent linkage instead of a linker to covalently attach to linkers together to produce a multi-binding compound. In this embodiment, q is equal to 0 and X does not have the structure represented by Formula III. In another one of its method aspects, this invention is directed to a method for treating the symptoms associated with Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthritis, cystitis, irritable bowel syndrome, pain, migraine headaches, asthma, bronchitis, allergic rhinitis, or inhibiting chemotherapy induced emesis in a mammal mediated by neurokinin receptors, which method comprises administering to said mammal a therapeutically effective amount of a pharmaceutical composition comprising a pharmaceutically acceptable excipient and one or more multi-binding compounds represented by Formula I or II; wherein each of said ligands comprises a ligand domain capable of binding to a neurokinin receptor of a mammal, thereby inhibiting the action of tachykinin agonists, such as Substance P, NKA and NKB at the neurokinin receptor and modulating the diseases and conditions resulting therefrom. In still another of its method aspects, q is equal to 0 and X comprises a covalent linkage instead of a linker, wherein X does not have the structure represented by Formula III. A preferred embodiment is the use of pharmaceutical compositions comprising ligands L or L' having the structure of Formula (A) or (B) and linkers X or X' having the structure of Formula (III), where q is less than p. More preferable is the use of such pharmaceutical compositions comprising a ligand-to- linker attachment selected from any of the above defined linkages la, lb and lc and their pharmaceutically acceptable salts to inhibit the binding of the natural agonists, such as Substance P, NKA and NKB, to the neurokinin receptors, NK,, NK 2 and NK 3 , in mammals. Most preferably, the multi-binding compounds comprise ligands with ligand binding domains capable of selectively binding to the NK, receptor in mammals. In still another preferred embodiment, X or X' does not have the structure of Formula III and q is equal to 0. This invention is also directed to general synthetic methods for generating large libraries of diverse multimeric compounds which multimeric compounds are candidates for possessing multibinding properties with respect to the neurokinin receptors. The diverse multimeric compound libraries pr vided by this invention are synthesized by combining a linker or linkers with a ligand or ligands to provide for a library of multimeric compounds wherein the linker and ligand each have complementary functional groups permitting covalent linkage. The library of linkers is preferably selected to have diverse properties such as valency, linker length, linker geometry and rigidity, hydrophilicity or hydrophobicity, amphiphilicity, acidity, basicity and polarability and /or polarization. The library of ligands is preferably selected to have diverse attachment points on the same ligand, different functional groups at the same site of otherwise the same ligand, and the like. This invention is also directed to libraries of diverse multimeric compounds which multimeric compounds are candidates for possessing multibinding properties with respect to the neurokinin receptors. These libraries are prepared via the methods described above and permit the rapid and efficient evaluation of what molecular constraints impart multibinding properties to a ligand or a class of ligands targeting the neurokinin receptors. Accordingly, in one of its method aspects, this invention is directed to a method for identifying multimeric ligand compounds possessing multibinding properties with respect to the neurokinin receptors which method comprises: (a) identifying a ligand or a mixture of ligands which bind to neurokinin receptors wherein each ligand contains at least one reactive functionality; (b) identifying a library of linkers wherein each linker in said library comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the ligand or mixture of ligands identified in (a) with the library of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands; and (d) assaying the multimeric ligand compounds produced in (c) above to identify multimeric ligand compounds possessing multibinding properties. In another of its method aspects, this invention is directed to a method for identifying multimeric ligand compounds possessing multibinding properties which method comprises: (a) identifying a library of ligands which bind to neurokinin receptors wherein each ligand contains at least one reactive functionality; (b) identifying a linker or mixture of linkers wherein each linker comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the library of ligands identified in (a) with the linker or mixture of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands; and (d) assaying the multimeric ligand compounds produced in (c) above to identify multimeric ligand compounds possessing multibinding properties. The preparation of the multimeric ligand compound library is achieved by either the sequential or concurrent combination of the two or more stoichiometric equivalents of the ligands identified in (a) with the linkers identified in (b). Sequential addition is preferred when a mixture of different ligands is employed to ensure heteromeric or multimeric compounds are prepared. Concurrent addition of the ligands occurs when at least a portion of the multimer compounds prepared are homomultimeric compounds. The assay protocols recited in (d) can be conducted on the multimeric ligand compound library produced in (c) above, or preferably, each member of the library is isolated by preparative liquid chromatography mass spectrometry (LCMS). In one of its composition aspects, this invention is directed to a library of multimeric ligand compounds which may possess multivalent properties which library is prepared by the method comprising: (a) identifying a ligand or a mixture of ligands which bind to neurokinin receptors wherein each ligand contains at least one reactive functionality; (b) identifying a library of linkers wherein each linker in said library comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; and (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the ligand or mixture of ligands identified in (a) with the library of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands. In another of its composition aspects, this invention is directed to a library of multimeric ligand compounds which bind to neurokinin receptors which may possess multivalent properties which library is prepared by the method comprising: (a) identifying a library of ligands which bind to neurokinin receptors wherein each ligand contains at least one reactive functionality; (b) identifying a linker or mixture of linkers wherein each linker comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; and (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the library of ligands identified in (a) with the linker or mixture of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands. In a preferred embodiment, the library of linkers employed in either the methods or the library aspects of this invention is selected from the group comprising flexible linkers, rigid linkers, hydrophobic linkers, hydrophilic linkers, linkers of different geometry, acidic linkers, basic linkers, linkers of different polarization, and/or polarability and amphiphilic linkers. For example, in one embodiment, each of the linkers in the linker library may comprise linkers of different chain length and/or having different complementary reactive groups. Such linker lengths can preferably range from about 2 to 100 A. In another preferred embodiment, the ligand or mixture of ligands is selected to have reactive functionality at different sites on the ligands in order to provide for a range of orientations of said ligand on said multimeric ligand compounds. Such reactive functionality includes, by way of example, carboxylic acids, carboxylic acid halides, carboxyl esters, amines, halides,pseudohalides, isocyanates, vinyl unsaturation, ketones, aldehydes, thiols, alcohols, boronates, anhydrides, and precursors thereof. It is understood, of course, that the reactive functionality on the ligand is selected to be complementary to at least one of the reactive groups on the linker so that a covalent linkage can be formed between the linker and the ligand. In other embodiments, the multimeric ligand compound is homomeric (i.e., each of the ligands is the same, although it may be attached at different points) or heteromeric (i.e., at least one of the ligands is different from the other ligands). In addition to the combinatorial methods described herein, this invention provides for an iterative process for rationally evaluating what molecular constraints impart multibinding properties to a class of multimeric compounds or ligands targeting the neurokinin receptors. Specifically, this method aspect is directed to a method for identifying multimeric ligand cor .pounds possessing multibinding properties with respect to the neurokinin receptors which method comprises: (a) preparing a first collection or iteration of multimeric compounds which is prepared by contacting at least two stoichiometric equivalents of the ligand or mixture of ligands which target the neurokinin receptors with a linker or mixture of linkers wherein said ligand or mixture of ligands comprises at least one reactive functionality and said linker or mixture of linkers comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand wherein said contacting is conducted under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands; (b) assaying said first collection or iteration of multimeric compounds to assess which if any of said multimeric compounds possess multibinding properties; (c) repeating the process of (a) and (b) above until at least one multimeric compound is found to possess multibinding properties; (d) evaluating what molecular constraints imparted multibinding properties to the multimeric compound or compounds found in the first iteration recited in (a)- (c) above; (e) creating a second collection or iteration of multimeric compounds which elaborates upon the particular molecular constraints imparting multibinding properties to the multimeric compound or compounds found in said first iteration; (f) evaluating what molecular constraints imparted enhanced multibinding properties to the multimeric compound or compounds found in the second collection or iteration recited in (e) above; (g) optionally repeating steps (e) and (f) to further elaborate upon said molecular constraints. Preferably, steps (e) and (f) are repeated at least two times, more preferably at from 2-50 times, even more preferably from 3 to 50 times, and still more preferably at least 5-50 times. BRIEF DESCRIPTION OF THE DRAWINGS Figure IA illustrates the ligand class utilized in the present invention; Figure IB illustrates the preferred ligand class utilized in the present invention; Figure 2 illustrates representative monovalent ligand compounds useful for the present invention; Figure 3 illustrates representative multivalent compounds of Formula I in accordance with the invention; Figure 4 illustrates representative types of linker end groups for use in preparing the multi-binding compounds of Formula I and the ligand-to-linker attachment of type la, using the preferred ligand class Formula (B) illustrated in Figure IB; Figures 5A-5C illustrate reaction schemes for preparing specific multi- binding compounds from the preferred ligands of Figure 2 in accordance with Figure 4; Figure 6A illustrates the reaction scheme for preparing multi-binding compounds from the preferred ligand class of Formula (B) having ligand-to-linker attachment of type lc of this invention; Figure 6B illustrates the reaction scheme for preparing a specific multi- binding compound from one of the preferred ligands of Figure 2 in accordance with Figure 6A; Figure 7 illustrates a reaction scheme for preparing a monovalent ligand of Figure IB that is used in Figure 6B from a precursor ligand compound of Formula (A); Figures 8 and 10 illustrate reaction schemes for preparing multi-binding compounds having the ligand-to-linker attachment type lb from ligand compounds of Formula (A); and Figures 9 and 11 illustrate reaction schemes for preparing specific multi- binding compounds of Figures 8 and 10, respectively. Figure 12 illustrates examples of multibinding compounds comprising 2 ligands attached in different forms to a linker. Figure 13 illustrates examples of multibinding compounds comprising 3 ligands attached in different forms to a linker. Figure 14 illustrates examples of multibinding compounds comprising 4 ligands attached in different forms to a linker. Figure 15 illustrates examples of multibinding compounds comprising 5-10 ligands attached in different forms to a linker. DETAILED DESCRIPTION OF THE INVENTION Ligand (drug) interactions with cellular receptors are controlled by molecular interaction/recognition between the ligand and the receptor. In turn, such interaction can result in modulation or disruption of the biological processes/functions of these receptors and, in some cases, leads to cell death. Accordingly, when cellular receptors mediate mammalian pathologic conditions, interactions of the ligand with the cellular receptor can be used to treat these conditions. Of particular interest are mammalian neurokinin receptors which are known to modulate conditions in mammals, such as Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthπtis, osteoarthritis, irritable bowel syndrome, cystitis, asthma, bronchitis, allergic rhinitis, pain, migraine headaches, or chemotherapy induced emetic conditions. As noted above, this invention is directed, in part, to multi-binding compounds that bind neurokinin receptors. The "affinity" and "specificity" of the neurokinin receptors and a ligand thereto are dependent upon the complementarity of molecular binding surfaces and the energetic consequences of complexation (i.e., the net difference in free energy ΔG between bound and free states). Affinity is sometimes quantified by the equilibrium constant of complex formation, the ratio of on/off rate constants, and/or by the free energy f complex formation. Specificity relates to the difference in binding affinity of a ligand for different cellular receptors. The multi-binding compounds of this invention are capable of acting as multi-binding agents and the suφrising activity of these compounds arises at least in part from their ability to bind in a multivalent manner with mammalian neurokinin receptors. Multivalent binding interactions are characterized by the concurrent interaction of multiple ligands with multiple ligand binding sites on one or more neurokinin receptors. Multivalent interactions differ from collections of individual monovalent interactions by imparting enhanced biological and/or therapeutic effect. Just as multivalent binding can amplify binding affinities, it can also amplify differences in binding affinities, resulting in enhanced binding specificity as well as affinity. When discussing such compounds, compositions or methods, the following terms have the following meanings unless otherwise indicated. Any undefined terms have their art recognized meanings. The term "alkyl" refers to a monoradical branche.. or unbranched saturated hydrocarbon chain preferably having from 1 to 40 carbon atoms, more preferably 1 to 10 carbon atoms ("lower alkyl"), and even more preferably 1 to 6 carbon atoms. This term is exemplified by groups such as methyl, ethyl, /.-propyl, iso-pτopy\, -butyl, wo-butyl, .-hexyl, n-decyl, tetradecyl, and the like. The term "substituted alkyl" refers to an alkyl group as defined above, having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl and -S0 2 -heteroaryl. The term "alkylene" refers to a diradical of a branched or unbranched saturated hydrocarbon chain, preferably having from 1 to 40 carbon atoms, more preferably 1 to 10 carbon atoms and even more preferably 1 to 6 carbon atoms. This term is exemplified by groups such as methylene (-CH 2 -), ethylene (-CH 2 CH 2 -), the propylene isomers (e.g., -CH 2 CH 2 CH 2 - and -CH(CH 3 )CH 2 -) and the like. The term "substituted alkylene" refers to an alkylene group, as defined above, having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, - SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -S0 2 -aryl and -SO 2 -heteroaryl. Additionally, such substituted alkylene groups include those where 2 substituents on the alkylene group are fused to form one or more cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heterocyclic or heteroaryl groups fused to the alkylene group. Preferably such fused groups contain from 1 to 3 fused ring structures. The term "alkaryl" refers to the groups -alkylene-aryl and -substituted alkylene-aryl where alkylene, substituted alkylene and aryl are defined herein. Such alkaryl groups are exemplified by benzyl, phenethyl and the like. The term "alkoxy" refers to the groups alkyl-O-, alkenyl-O-, cycloalkyl-O-, cycloalkenyl-O-, and alkynyl-O-, where alkyl, alkenyl, cycloalkyl, cycloalkenyl, and alkynyl are as defined herein. Preferred alkoxy groups are alkyl-O- and include, by way of example, methoxy, ethoxy, n-propoxy, .so-propoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, w-hexoxy, 1 ,2-dimethylbutoxy, and the like. The term "substituted alkoxy" refers to the groups substituted alkyl-O-, substituted alkenyl-O-, substituted cycloalkyl-O-, substituted cycloalkenyl-O-, and substituted alkynyl-O- where substituted alkyl, substituted alkenyl, substituted cycloalkyl, substituted cycloalkenyl and substituted alkynyl are as defined herein. The term "alkylalkoxy" refers to the groups -alkylene-O-alkyl, alkylene-O-substituted alkyl, substituted alkylene-O-alkyl and substituted alkylene-O-substituted alkyl wherein alkyl, substituted alkyl, alkylene and substituted alkylene are as defined herein. Preferred alkylalkoxy groups are alkylene-O-alkyl and include, by way of example, methylenemethoxy (-CH 2 OCH 3 ), ethylenemethoxy (-CH 2 CH 2 OCH 3 ), «-propylene-/.sO-propoxy (-CH 2 CH 2 CH 2 OCH(CH 3 ) 2 ), methylene-t-butoxy (-CH 2 -O-C(CH 3 ) 3 ) and the like. The term "alkylthioalkoxy" refers to the group -alkylene-S-alkyl, alkylene-S-substituted alkyl, substituted alkylene-S-alkyl and substituted alkylene- S-substituted alkyl wherein alkyl, substituted alkyl, alkylene and substituted alkylene are as defined herein. Preferred alkylthioalkoxy groups are alkylene-S- alkyl and include, by way of example, methylenethiomethoxy (-CH 2 SCH 3 ), ethylenethiomethoxy (-CH 2 CH 2 SCH 3 ), .z-propylene-.so-thiopropoxy (-CH 2 CH 2 CH 2 SCH(CH 3 ) 2 ), methylene-t-thiobutoxy (-CH 2 SC(CH 3 ) 3 ) and the like. The term "alkenyl" refers to a monoradical of a branched or unbranched unsaturated hydrocarbon group preferably having from 2 to 40 carbon atoms, more preferably 2 to 10 carbon atoms and even more preferably 2 to 6 carbon atoms and having at least 1 and preferably from 1-6 sites of vinyl unsaturation. Preferred alkenyl groups include ethenyl (-CH=CH 2 ), n-propenyl (-CH 2 CH=CH 2 ), wo-propenyl (-C(CH 3 )=CH 2 ), and the like. The term "substituted alkenyl" refers to an alkenyl group as defined above having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic,. heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl and -SO 2 -heteroaryl. The term "alkenylene" refers to a diradical of a branched or unbranched unsaturated hydrocarbon group preferably having from 2 to 40 carbon atoms, more preferably 2 to 10 carbon atoms and even more preferably 2 to 6 carbon atoms and having at least 1 and preferably from 1-6 sites of vinyl unsaturation. This term is exemplified by groups such as ethenylene (-CH=CH-), the propenylene isomers (e.g., -CH 2 CH=CH- and -C(CH 3 )=CH-) and the like. The term "substituted alkenylene" refers to an alkenylene group as defined above having from 1 to 5 substituents, and preferably from 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, - SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -S0 2 -aryl and -S0 2 -heteroaryl. Additionally, such substituted alkenylene groups include those where 2 substituents on the alkenylene group are fused to form one or more cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heterocyclic or heteroaryl groups fused to the alkenylene group. The term "alkynyl" refers to a monoradical of an unsaturated hydrocarbon preferably having from 2 to 40 carbon atoms, more preferably 2 to 20 carbon atoms and even more preferably 2 to 6 carbon atoms and having at least 1 and preferably from 1-6 sites of acetylene (triple bond) unsaturation. Preferred alkynyl groups include ethynyl (-C≡CH), propargyl (-CH 2 C≡CH) and the like. The term "substituted alkynyl" refers to an alkynyl group as defined above having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cyclo kyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl and -SO 2 -heteroaryl. The term "alkynylene" refers to a diradical of an unsaturated hydrocarbon preferably having from 2 to 40 carbon atoms, more preferably 2 to 10 carbon atoms and even more preferably 2 to 6 carbon atoms and having at least 1 and preferably from 1-6 sites of acetylene (triple bond) unsaturation. Preferred alkynylene groups include ethynylene (-C≡C-), propargylene (-CH 2 C≡C-) and the like. The term "substituted alkynylene" refers to an alkynylene group as defined above having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, - SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl and -SO 2 -heteroaryl The term "acyl" refers to the groups HC(O)-, alkyl-C(O)-, substituted alkyl- C(O)-, cycloalkyl-C(O)-, substituted cycloalkyl-C(O)-, cycloalkenyl-C(O)-, substituted cycloalkenyl-C(O)-, aryl-C(O)-, heteroaryl-C(O)- and heterocyclic- C(O)- where alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "acylamino" or "aminocarbonyl" refers to the group -C(O)NRR where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, heterocyclic or where both R groups are joined to form a heterocyclic group (e.g., moφholino) wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "aminoacyl" refers to the group -NRC(O)R where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "aminoacyloxy" or "alkoxycarbonylamino" refers to the group -NRC(O)OR where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "acyloxy" refers to the groups alkyl-C(O)O-, substituted alkyl- C(O)O-, cycloalkyl-C(O)O-, substituted cycloalkyl-C(O)O-, aryl-C(O)O-, heteroaryl-C(O)O-, and heterocyclic-C(O)O- wherein alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, heteroaryl, and heterocyclic are as defined herein. The term "aryl" refers to an unsaturated aromatic carbocyclic group of from 6 to 20 carbon atoms having a single ring (e.g., phenyl) or multiple condensed (fused) rings (e.g., naphthyl or anthryl). Preferred aryls include phenyl, naphthyl and the like. Unless otherwise constrained by the definition for the aryl substituent, such aryl groups can optionally be substituted with from 1 to 5 substituents, preferably 1 to 3 substituents, selected from the group consisting of acyloxy, hydroxy, thiol, acyl, alkyl, alkoxy, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, substituted alkyl, substituted alkoxy, substituted alkenyl, substituted alkynyl, substituted cycloalkyl, substituted cycloalkenyl, amino, substituted amino, aminoacyl, acylamino, alkaryl, aryl, aryloxy, azido, carboxyl, carboxylalkyl, cyano, halo, nitro, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, aminoacyloxy, oxyacylamino, thioalkoxy, substituted thioalkoxy, thioaryloxy, thioheteroaryloxy, -SO-alkyl, -SO- substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, - SO 2 -aryl, -SO 2 -heteroaryl and trihalomethyl. Preferred aryl substituents include alkyl, alkoxy, halo, cyano, nitro, trihalomethyl, and thioalkoxy. The term "aryloxy" refers to the group aryl-O- wherein the aryl group is as defined above including optionally substituted aryl groups as also defined above. The term "arylene" refers to the diradical derived from aryl (including substituted aryl) as defined above and is exemplified by 1 ,2-phenylene, 1,3- phenylene, 1 ,4-phenylene, 1 ,2-naphthylene and the like. The term "amino" refers to the group -NH 2 . The term "substituted amino refers to the group -NRR where each R is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic provided that both R's are not hydrogen. The term "carboxyalkyl" or "alkoxycarbonyl" refers to the groups "-C(O)O-alkyl", "-C(O)O-substituted alkyl", "-C(O)O-cycloalkyl", "-C(O)0- substituted cycloalkyl", "-C(O)O-alkenyl", "-C(O)O-substituted alkenyl", "-C(O)O-alkynyl" and "-C(O)O-substituted alkynyl" where alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, alkynyl and substituted alkynyl are as defined herein. The term "cycloalkyl" refers to cyclic alkyl groups of from 3 to 20 carbon atoms having a single cyclic ring or multiple condensed rings. Such cycloalkyl groups include, by way of example, single ring structures such as cyclopropyl, cyclobutyl, cyclopentyl, cyclooctyl, and the like, or multiple ring structures such as adamantanyl, and the like. The term "substituted cycloalkyl" refers to cycloalkyl groups having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl and -SO 2 -heteroaryl. The term "cycloalkenyl" refers to cyclic alkenyl groups of from 4 to 20 carbon atoms having a single cyclic ring and at least one point of internal unsaturation. Examples of suitable cycloalkenyl groups include, for instance, cyclobut-2-enyl, cyclopent-3-enyl, cyclooct-3-enyl and the like. The term "substituted cycloalkenyl" refers to cycloalkenyl groups having from 1 to 5 substituents, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, 'cyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, -SO 2 -alkyl, -SO 2 -substituted alkyl, -SO,-aryl and -SO 2 -heteroaryl. The term "halo" or "halogen" refers to fluoro, chloro, bromo and iodo. The term "heteroaryl" refers to an aromatic group of from 1 to 15 carbon atoms and 1 to 4 heteroatoms selected from oxygen, nitrogen and sulfur within at least one ring (if there is more than one ring). Unless otherwise constrained by the definition for the heteroaryl substituent, such heteroaryl groups can be optionally substituted with 1 to 5 substituents, preferably 1 to 3 substituents, selected from the group consisting of acyloxy, hydroxy, thiol, acyl, alkyl, alkoxy, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, substituted alkyl, substituted alkoxy, substituted alkenyl, substituted alkynyl, substituted cycloalkyl, substituted cycloalkenyl, amino, substituted amino, aminoacyl, acylamino, alkaryl, aryl, aryloxy, azido, carboxyl, carboxylalkyl, cyano, halo, nitro, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, aminoacyloxy, oxyacylamino, thioalkoxy, substituted thioalkoxy, thioaryloxy, thioheteroaryloxy, -SO-alkyl, -SO-substituted alkyl, -SO-aryl, -SO-heteroaryl, - SO 2 -alkyl, -SO 2 -substituted alkyl, -SO 2 -aryl, -SO 2 -heteroaryl and trihalomethyl. Preferred aryl substituents include alkyl, alkoxy, halo, cyano, nitro, trihalomethyl, and thioalkoxy. Such heteroaryl groups can have a single ring (e.g., pyridyl or furyl) or multiple condensed rings (e.g., indolizinyl or benzothienyl). Preferred heteroaryls include pyridyl, pyrrolyl and furyl. The term "heteroaryloxy" refers to the group heteroaryl-O-. The term "heteroarylene" refers to the diradical group derived from heteroaryl (including substituted heteroaryl), as defined above, and is exemplified by the groups 2,6-pyridylene, 2,4-pyridiylene, 1 ,2-quinolinylene, 1 ,8- quinolinylene, 1,4-benzofiιranylene, 2,5-pyridnylene, 2,5-indolenyl and the like. The term "heterocycle" or "heterocyclic" refers to a monoradical saturated unsaturated group having a single ring or multiple condensed rings, from 1 to 40 carbon atoms and from 1 to 10 hetero atoms, preferably 1 to 4 heteroatoms, selected from nitrogen, sulfur, phosphorus, and/or oxygen within the ring. Unless otherwise constrained by the definition for the heterocyclic substituent, such heterocyclic groups can be optionally substituted with 1 to 5, and preferably 1 to 3 substituents, selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, keto, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclic, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, -SO-alkyl, -SO- substituted alkyl, -SO-aryl, -SO-heteroaryl, -S0 2 -alkyl, -SO 2 -substituted alkyl, - SO 2 -aryl and -SO 2 -heteroaryl. Such heterocyclic groups can have a single ring or multiple condensed rings. Preferred heterocyclics include moφholino, piperidinyl, and the like. Examples of nitrogen heterocycles and heteroaryls include, but are not limited to, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, naphthylpyridine, quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, phenoxazine, phenothiazine, imidazolidine, imidazoline, piperidine, piperazine, indoline, moφholino, piperidinyl, tetrahydro furanyl, and the like as well as N-alkoxy-nitrogen containing heterocycles. A preferred class of heterocyclics include "crown compounds" which refers to a specific class of heterocyclic compounds having one or more repeating units of the formula [-(CH 2 -) m Y-] where m is > 2, and Y' at each separate occurrence can be O, N, S or P. Examples of crown compounds include, by way of example only, [-(CH 2 ) 3 -NH-] 3 , [-((CH 2 ) 2 -O) 4 -((CH 2 ) 2 -NH) 2 ] and the like. Typically such crown compounds can have from 3 to 10 heteroatoms and 8 to 40 carbon atoms. The term "heterocyclooxy" refers to the group heterocyclic-O-. The term "thioheterocyclooxy" refers to the group heterocyclic-S-. The term "heterocyclene" refers to the diradical group formed from a heterocycle, as defined herein, and is exemplified by the groups 2,6-moφholino, 2,5-moφholino and the like. The term "oxyacylamino" or "aminocarbonyloxy" refers to the group -OC(O)NRR where each R is independently hydrogen, alkyl, substituted alkyl, aryl, heteroaryl, or heterocyclic wherein alkyl, substituted alkyl, aryl, heteroaryl and heterocyclic are as defined herein. The term "spiro-attached cycloalkyl group" refers to a cycloalkyl group attached to another ring via one carbon atom common to both rings. The term "thiol" refers to the group -SH. The term "thioalkoxy" refers to the group -S-alkyl. The term "substituted thioalkoxy" refers to the group -S-substituted alkyl. The term "thioaryloxy" refers to the group aryl-S- wherein the aryl group is as defined above including optionally substituted aryl groups also defined above. The term "thioheteroaryloxy" refers to the group heteroaryl-S- wherein the heteroaryl group is as defined above including optionally substituted aryl groups as also defmed above. As to any of the above groups which contain one or more substituents, it is understood, of course, that such groups do not contain any substitution or substitution patterns which are sterically impractical and/or synthetically non- feasible. In addition, the compounds of this invention include all stereochemical isomers arising from the substitution of these compounds, whether the isomers are those arising in the ligands, the linkers, or the multivalent constructs including the ligands and linkers. The term "pharmaceutically-acceptable salt" refers to salts which retain the biological effectiveness and properties of the multibinding compounds of this invention and which are not biologically or otherwise undesirable. In many cases, the multibinding compounds of this invention are capable of forming acid and/or base salts by virtue of the presence of amino and/or carboxyl groups or groups similar thereto. Pharmaceutically-acceptable base addition salts can be prepared from inorganic and organic bases. Salts derived from inorganic bases, include by way of example only, sodium, potassium, lithium, ammonium, calcium and magnesium salts. Salts derived from organic bases include, but are _.->t limited to, salts of primary, secondary and tertiary amines, such as alkyl amines, dialkyl amines, trialkyl amines, substituted alkyl amines, di(substituted alkyl) amines, tri(substituted alkyl) amines, alkenyl amines, dialkenyl amines, trialkenyl amines, substituted alkenyl amines, di(substituted alkenyl) amines, tri(substituted alkenyl) amines, cycloalkyl amines, di(cycloalkyl) amines, tri(cycloalkyl) amines, substituted cycloalkyl amines, disubstituted cycloalkyl amine, trisubstituted cycloalkyl amines, cycloalkenyl amines, di(cycloalkenyl) amines, tri(cycloalkenyl) amines, substituted cycloalkenyl amines, disubstituted cycloalkenyl amine, trisubstituted cycloalkenyl amines, aryl amines, diaryl amines, triaryl amines, heteroaryl amines, diheteroaryl amines, triheteroaryl amines, heterocyclic amines, diheterocyclic amines, triheterocyclic amines, mixed di- and tri-amines where at least two of the substituents on the amine are different and are selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, aryl, heteroaryl, heterocyclic, and the like. Also included are amines where the two or three substituents, together with the amino nitrogen, form a heterocyclic or heteroaryl group. Examples of suitable amines include, by way of example only, isopropylamine, trimethyl amine, diethyl amine, tri(z ' 5o-propyl) amine, tri(«- propyl) amine, ethanolamine, 2-dimethylaminoethanol, tromethamine, lysine, arginine, histidine, caffeine, procaine, hydrabamine, choline, betaine, ethylenediamine, glucosamine, N-alkylglucamines, theobromine, purines, piperazine, piperidine, moφholine, N-ethylpiperidine, and the like. It should also be understood that other carboxylic acid derivatives would be useful in the practice of this invention, for example, carboxylic acid amides, including carboxamides, lower alkyl carboxamides, dialkyl carboxamides, and the like. Pharmaceutically acceptable acid addition salts may be prepared from inorganic and organic acids. Salts derived from inorganic acids include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like. Salts derived from organic acids include acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, -toluene-sulfonic acid, salicylic acid, and the like. The term "pharmaceutically-acceptable cation" refers to the cation of a pharmaceutically-acceptable salt. The term "protecting group" or "blocking group" refers to any group which when bound to one or more hydroxyl, thiol, amino or carboxyl groups of the compounds (including intermediates thereof) prevents reactions from occurring at these groups and which protecting group can be removed by conventional chemical or enzymatic steps to reestablish the hydroxyl, thiol, amino or carboxyl group. The particular removable blocking group employed is not critical and preferred removable hydroxyl blocking groups include conventional substituents such as allyl, benzyl, acetyl, chloroacetyl, thiobenzyl, benzylidine, phenacyl, t-butyl- diphenylsilyl and any other group that can be introduced chemically onto a hydroxyl functionality and later selectively removed either by chemical or enzymatic methods in mild conditions compatible with the nature of the product. Preferred removable thiol blocking groups include disulfide groups, acyl groups, benzyl groups, and the like. Preferred removable amino blocking groups include conventional substituents such as t-butyoxycarbonyl (t-BOC), benzyloxycarbonyl (CBZ), fluorenylmethoxycarbonyl (FMOC), allyloxycarbonyl (ALOC), and the like which can be removed by conventional conditions compatible with the nature of the product. Preferred carboxyl protecting groups include esters such as methyl, ethyl, propyl, t-butyl etc. which can be removed by mild conditions compatible with the nature of the product. The term "optional" or "optionally" means that the subsequently described event, circumstance or substituent may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. The term "ligand" as used herein denotes a compound that is an agonist, partial agonist, inverse agonist, inverse partial agonist, or antagonist of the neurokinin receptors. The specific region or regions of the ligand that is (are) recognized by the receptor is designated as the "ligand domain". A ligand may be either capable of binding to a receptor by itself, or may require the presence of one or more non-ligand components for binding (e.g., Ca *2 , Mg "2 or a water molecule is required for the binding of a ligand to various ligand binding sites). Examples of ligands useful in this invention are described herein. Those skilled in the art will appreciate that portions of the ligand structure that are not essential for specific molecular recognition and binding activity may be varied substantially, replaced or substituted with unrelated structures (for example, with ancillary groups as defined below) and, in some cases, omitted entirely without affecting the binding interaction. The primary requirement for a ligand is that it has a ligand domain as defined above. It is understood that the term ligand is not intended to be limited to compounds known to be useful in binding to neurokinin receptors (e.g., known drugs). Those skilled in the art will understand that the term ligand can equally apply to a molecule that is not normally associated with receptor binding properties. In addition, it should be noted that ligands that exhibit marginal activity or lack useful activity as monomers can be highly active as multivalent compounds because of the benefits conferred by multivalency. The term "multibinding compound or agent" refers to a compound that is capable of multivalency, as defined below, and which has 2-10 ligands covalently bound to one or more linkers which may be the same or different. Multibinding compounds provide a biological and/or therapeutic effect greater than the aggregate of unlinked ligands equivalent thereto which are made available for binding. That is to say that the biological and/or therapeutic effect of the ligands attached to the multibinding compound is greater than that achieved by the same amount of unlinked ligands made available for binding to the ligand binding sites (receptors). The phrase "increased biological or therapeutic effect" includes, for example: increased affinity, increased selectivity for target, increased specificity for target, increased potency, increased efficacy, decreased toxicity, improved duration of activity or action, decreased side effects, increased therapeutic index, improved bioavailability, improved pharmacokinetics, improved activity spectrum, and the like. The multibinding compounds of this invention will exhibit at least one and preferably more than one of the above-mentioned effects. The term "potency" refers to the minimum concentration at which a ligand is able to achieve a desirable biological or therapeutic effect. The potency of a ligand is typically proportional to its affinity for its ligand binding site. In some cases, the potency may be non-linearly correlated with its affinity. In comparing the potency of two drugs, e.g., a multibinding agent and the aggregate of its unlinked ligand, the dose-response curve of each is determined under identical test conditions (e.g., in an in vitro or in vivo assay, in an appropriate animal model). The finding that the multibinding agent produces an equivalent biological or therapeutic effect at a lower concentration than the aggregate unlinked ligand is indicative of enhanced potency. The term "univalency" as used herein refers to a single binding interaction between one ligand as defined herein with one ligand bir ling site as defined herein. It should be noted that a compound having multiple copies of a ligand (or ligands) exhibits univalency when only one ligand is interacting with a ligand binding site. Examples of univalent interactions are depicted below. The term "multivalency" as used herein refers to the concurrent binding of from 2 to 10 linked ligands (which may be the same or different) and two or more corresponding receptors (ligand binding sites) on one or more receptors which may be the same or different. For example, two ligands connected through a linker that bind concurrently to two ligand binding sites would be considered as bivalency; three ligands thus connected would be an example of trivalency. An example of trivalent binding, illustrating a multibinding compound bearing three ligands versus a monovalent binding interaction, is shown below: Univalent Interaction Trivalent Interaction It should be understood that all compounds that contain multiple copies of a ligand attached to a linker or to linkers do not necessarily exhibit the phenomena of multivalency, i.e., that the biological and/or therapeutic effect of the multibinding agent is greater than the sum of the aggregate of unlinked ligands made available for binding to the ligand binding site (receptor). For multivalency to occur, the ligands that are connected by a linker or linkers have to be presented to their ligand binding sites by the linker(s) in a specific manner in order to bring about the desired ligand-orienting result, and thus produce a multibinding event. The term "selectivity" or "specificity" is a measure of the binding preferences of a ligand for different ligand binding sites (receptors). The selectivity of a ligand with respect to its target ligand binding site relative to another ligand binding site is given by the ratio of the respective values of K d (i.e., the dissociation constants for each ligand-receptor complex) or, in cases where a biological effect is observed below the K d , the ratio of the respective EC 50 's (i.e., the concentrations that produce 50% of the maximum response for the ligand interacting with the two distinct ligand binding sites (receptors)). The term "ligand binding site" denotes the site on the neurokinin receptors that recognizes a ligand domain and provides a binding partner for the ligand. The ligand binding site may be defined by monomeric or multimeric structures. This interaction may be capable of producing a unique biological effect, for example, agonism, antagonism, modulatory effects, may maintain an ongoing biological event, and the like. However, in one embodiment, the ligand(s) merely bind to a ligand binding site and do not have agonistic or antagonistic activity. The terms "agonism" and "antagonism" are well known in the art. Ligands which are full agonists are ligands which when bound trigger the maximum activity seen by the natural ligands. Ligands which are partial agonists are ligands which when bound trigger sub-maximum activity. Ligands which are antagonists are ligands that when bound, inhibit or prevent the activity arising from a natural ligand binding to the receptor. Antagonists may be of the surmountable class (results in the parallel displacement of the dose-response curve of the agonist to the right in a dose dependent fashion without reducing the maximal response for the agonist) or insurmountable class (results in depression of the maximal response for a given agonist with or without the parallel shift). Ligands which are inverse agonists are ligands that, when bound, decrease the basal activity of the unbound receptor or which provide an activity opposive of the natural agonist. Ligands have measurable properties that relate to the interaction of the ligand and the receptor. These include the affinity of the ligand for the receptor, which relates to the energetics of the binding, the efficacy of the ligand for the receptor, which relates to the functional downstream activity of the ligand, the kinetics of the ligand for the receptor, which defines the onset of action and the duration of action, and the desensitization of the receptor for the ligand. Selectivity defines the ratio of the affinity and/or efficacy of a ligand across two receptors. The term "modulatory effect" refers to the ability of the ligand to change the activity of an agonist or antagonist through binding to a ligand binding site. It is a combination of these properties which provides the foundation for defining the nature of the functional response. It should be recognized that the ligand binding sites of the receptor that participate in biological multivalent binding interactions are constrained to varying degrees by their intra- and inter-molecular associations (e.g., such macromolecular structures may be covalently joined to a single structure, noncovalently associated in a multimeric structure, embedded in a membrane or polymeric matrix, and so on) and therefore have less translational and rotational freedom than if the same structures were present as monomers in solution. The term "inert organic solvent" means a solvent which is inert under the conditions of the reaction being described in conjunction therewith including, by way of example only, benzene, toluene, acetonitrile, tetrahydrofuran, dimethylformamide, chloroform, methylene chloride, diethyl ether, ethyl acetate, acetone, methylethyl ketone, methanol, ethanol, propanol, isopropanol, t-butanol, dioxane, pyridine, and the like. Unless specified to the contrary, the solvents used in the reactions described herein are inert solvents. The "neurokinin receptors" are tachykinin receptors, which include neurokinin 1 (NK,), neurokinin 2 (NK 2 ) and neurokinin 3 (NK 3 ) receptors. The NK, receptor is the most predominant receptor of the three and is found in the CNS and peripheral nervous system. The NK 2 receptor is found in the peripheral nervous system with small amounts in the CNS. The NK 3 receptor is in the CNS and the bladder and intestine. The three receptors have varying affinities for three mammalian tachykinin ligand peptide neurotransmitters (agonists), substance P (SP), neurokinin A (NKA) and neurokinin B (NKB). The NK, has the highest affinity for SP, NK 2 has the highest affinity for NKA and NK 3 has the highest affinity for NKB. The tachykinin ligands share a common amino acid sequence at their carboxy terminal. The mammalian tachykinins contribute to the pathophysiology of a number of human diseases. As a result, efforts are underway in the pharmaceutical industry to develop increasingly more potent and selective tachykinin receptor antagonists to produce therapeutic ag nts for treatment of a variety of clinical disorders. 3 "Ligand" or "neurokinin ligand" or "tachykinin ligand" as used herein denotes a compound that is a binding partner for the neurokinin receptor and is bound thereto by complementarity. The specific region or regions of the ligand that is (are) recognized by the neurokinin receptor is designated as the "ligand domain". A ligand may be either capable of binding to a receptor by itself, or may require the presence of one or more non-ligand components for binding (e.g., Ca ~2 , Mg +2 or a water molecule). Accordingly, examples of ligands useful for this invention include those listed in Table 2 and illustrated in Figure 2 herein. Each of these ligands are being tested for there usefulness in the treatment of one of more of the following diseases or conditions: Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthritis, cystitis, irritable bowel syndrome, allergic rhinitis, osteoarthritis, pain, migraine headaches, asthma, bronchitis, and emesis in mammals. 22 The term "ligand" or "ligands" as used herein is intended to include the racemic forms of the ligands as well as individual enantiomers and diastereomers and non-racemic mixtures thereof. This applies to the linkers and multivalent compounds as well. The term "ligand precursor" refers to a compound that is a starting material or an intermediate in the synthesis of a completed ligand. The ligand precursor may be coupled to a linker with completion of ligand synthesis being carried out in a separate step. The ligand precursor may have the structure of Formula (A) (see for example, ligand precursors (60a) and (78) in Figures 9 and 1 1 ). A "multi-binding agent" or "multi-binding compound" refers to a compound that is capable of multivalency as defined below, and which has 2 to 10 ligands covalently bound to one or more linkers which may be the same or different wherein at least 1 of the ligands comprise a ligand domain capable of binding to one or more neurokinin receptors. It may be preferably in some instances that the ligand domain is selective for one neurokinin receptor (i.e., to more effectively treat a particular disease mediated by only one neurokinin receptor). The multi-binding compound provides a biological and/or therapeutic effect greater than the aggregate of unlinked ligands equivalent thereto. That is to say that the biological and/or therapeutic effect of the ligands attached to the multi- binding compound is greater than that achieved by the same number of unlinked ligands made available for binding to the ligand binding sites on the receptor or receptors. The phrase "greater biologic and/or therapeutic effect" or "increased biologic and/or therapeutic effect" includes for example increased affinity for a target, increased specificity for a target, increased selectivity for the target, increased potency, increased efficacy, decreased toxicity, decreased side effects, increased duration of action, improved bioavailability, improved pharmacokinetics, improved activity spectrum, increased therapeutic index, and the like. The multi- binding compounds of this invention will exhibit at least one, and preferably more than one, of the above-mentioned effects. The term "emesis" is the act or instance of vomiting. An "emetic agent" is an agent that induces vomiting. Emesis also includes nausea. In this invention, emetic agents include compounds used in chemotherapy and radiation therapy. The term "chemotherapy induced emesis" refers to emetic episodes which are induced by exposure to chemotherapy and/or anti-cancer treatments such as treatment with, for example, cisplatin, adriamycin, apomoφhine, cyclohexamide, cyclophosphamide, copper sulphate, ipecacuanha, mustine and radiation, among others. Chemotherapy induced emetic episodes may be acute or may be delayed up to several days. There are generally three types of chemotherapy induced emesis seen clinically: acute, delayed and anticipatory (conditioned). 7 Acute chemotherapy induced nausea and vomiting generally is considered to be that which occurs within the first 24 hours following drug administration. 8 Delayed emesis is generally defined as emetic episodes starting about 24 hours or more following the last treatment. 7 This can be a serious complication for patients, as it can be protracted and severe and there are very few good treatment options for its prevention. 4 Conditioned or anticipatory emesis results from poor control of acute or delayed emesis. It is typically associated with anxiety prior to the next dose of chemotherapy, followed by nausea or vomiting before, during or possibly after the administration of chemotherapy. 7 The term "treatment" refers to any treatment of a pathologic condition in a mammal, particularly a human, and includes: (i) preventing the pathologic condition from occurring in a subject which may be predisposed to the condition but has not yet been diagnosed with the condition and, accordingly, the treatment constitutes prophylactic treatment for the disease condition; (ii) inhibiting the pathologic condition, i.e., arresting its development; (iii) relieving the pathologic condition, i.e., causing regression of the pathologic condition; or (iv) relieving the conditions mediated by the pathologic condition. The term "pathologic condition which is modulated by treatment with a ligand" covers all disease states (i.e., pathologic conditions) which are generally acknowledged in the art to be usefully treated with a ligand for the neurokinin receptors in general, and those disease states which have been found to be usefully treated by a specific multibinding compound of our invention. The term "therapeutically effective amount" refers to that amount of multibinding compound which is sufficient to effect treatment, as defined above, when administered to a mammal in need of such treatment. The therapeutically effective amount will vary depending upon the subject and disease condition being treated, the weight and age of the subject, the severity of the disease condition, the manner of administration and the like, which can readily be determined by one of ordinary skill in the art. The term "linker", identified where appropriate by the symbol X, X' or X", refers to a group or groups that covalently links from 2 to 10 ligands (as identified above) in a manner that provides for a compound capable of multivalency. Among other features, the linker is a ligand-orienting entity that permits attachment of multiple copies of a ligand (which may be the same or different) thereto. In some cases, the linker may itself be biologically active. The term "linker" does not, however, extend to cover solid inert supports such as beads, glass particles, fibers, and the like. But it is understood that the multibinding compounds of this invention can be attached to a solid support if desired. For example, such attachment to solid supports can be made for use in separation and purification processes and similar applications. The term "library" refers to at least 3, preferably from 10 2 to 10 9 and more preferably from 10 2 to 10 4 multimeric compounds. Preferably, these compounds are prepared as a multiplicity of compounds in a single solution or reaction mixture which permits facile synthesis thereof. In one embodiment, the library of multimeric compounds can be directly assayed for multibinding properties. In another embodiment, each member of the library of multimeric compounds is first isolated and, optionally, characterized. This member is then assayed for multibinding properties. The term "collection" refers to a set of multimeric compounds which are prepared either sequentially or concurrently (e.g., combin torially). The collection comprises at least 2 members; preferably from 2 to 10 9 members and still more preferably from 10 to 10 4 members. The term "multimeric compound" refers to compounds comprising from 2 to 10 ligands covalently connected through at least one linker which compounds may or may not possess multibinding properties (as defined herein). The term "pseudohalide" refers to functional groups which react in displacement reactions in a manner similar to a halogen. Such functional groups include, by way of example, mesyl, tosyl, azido and cyano groups. Linkers The extent to which multivalent binding is realized depends upon the efficiency with which the linker or linkers that joins the ligands presents these ligands to the array of available ligand binding sites. Beyond presenting these ligands for multivalent interactions with ligand binding sites, the linker or linkers spatially constrains these interactions to occur within dimensions defined by the linker or linkers. Thus, the structural features of the linker (valency, geometry, orientation, size, flexibility, chemical composition, etc.) are features of multibinding agents that play an important role in determining their activities. The linkers used in this invention are selected to allow multivalent binding of ligands to the ligand binding sites of neurokinin receptors, wherever such sites are located on the receptor structure. The ligands are covalently attached to the linker or linkers using conventional chemical techniques providing for covalent linkage of the ligand to the linker or linkers. Reaction chemistries resulting in such linkages are well known in the art and involve the use of complementary functional groups on the linker and ligand. Preferably, the complementary functional groups on the linker are selected relative to the functional groups available on the ligand for bonding or which can be introduced onto the ligand for bonding. Again, such complementary functional groups are well known in the art. For example, reaction between a carboxylic acid of either the linker or the ligand and a primary or secondary amine of the ligand or the linker in the presence of suitable, well-known activating agents results in formation of an amide bond covalently linking the ligand to the linker; reaction between an amine group of either the linker or the ligand and a sulfonyl halide of the ligand or the linker results in formation of a sulfonamide bond covalently linking the ligand to the linker; and reaction between an alcohol or phenol group of either the linker or the ligand and an alkyl or aryl halide of the ligand or the linker results in formation of an ether bond covalently linking the ligand to the linker. Table I below illustrates numerous complementary reactive groups and the resulting bonds formed by reaction there between. Table I First Reactive Group Second Reactive Group Linkage hydroxyl isocyanate urethane amine epoxide β-hydroxyamine sulfonyl halide amine sulfonamide carboxyl amine amide hydroxyl alkyl/aryl halide ether aldehyde amine NaCNBH 4 amine ketone amine/NaCNBH 4 amine amine isocyanate urea The linker is attached to the ligand at a position that retains ligand domain- ligand binding site interaction and specifically which permits the ligand domain of the ligand to orient itself to bind to the ligand binding site. Such positions and synthetic protocols for linkage are well known in the art. The term linker embraces everything that is not considered to be part of the ligand. The relative orientation in which the ligand domains are displayed derives from the particular point or points of attachment of the ligands to the linker, and on the framework geometry. The determination of where acceptable substitutions can be made on a ligand is typically based on prior knowledge of structure-activity relationships (SAR) of the ligand and/or congeners and/or structural information about ligand-receptor complexes (e.g., X-ray crystallography, NMR, and the like). Such positions and the synthetic methods for covalent attachment are well known in the art. Following attachment to the selected linker (or attachment to a significant portion of the linker, for example 2-10 atoms of the linker), the univalent linker-ligand conjugate may be tested for retention of activity in the relevant assay. For example, if a linker-ligand conjugate shows activity at a concentration of less than 1 mM, it is considered to be acceptable for use in constructing a multi-binding compound. The relative orientation in which the ligand domains are displayed to the receptors depends both on the particular point (or points) of attachment of the ligands to the linker, and on the framework geometry of the linker framework. The term linker embraces everything that is not considered to be part of the ligand, e.g., ancillary groups such as solubilizing groups, lipophilic groups, groups that alter pharmacodynamics or pharmacokinetics, groups that modify the diffusability of the multi-binding compound, groups that attach the ligand to the linker, groups that aid the ligand-orienting function of the linker, for example, by imparting flexibility or rigidity to the linker as a whole, or to a portion thereof, and so on. Suitable linkers for the present invention are illustrated in Figures 5A-5C, 9 and 1 1 and are discussed below. At present, it is preferred that the multi-binding agent is a bivalent compound, e.g., two ligands L that are covalently linked to linker X, or in one embodiment, two ligands L that are covalently linked together (when q =0). Methodology The linker, when covalently attached to multiple copies of the ligands, provides a biocompatible, substantially non-immunogenic multibinding compound. The biological activity of the multibinding compound is highly sensitive to the valency, geometry, composition, size, flexibility or rigidity, etc. of the linker and, in turn, on the overall structure of the multibinding compound, as well as the presence or absence of anionic or cationic charge, the relative hydrophobicity/hydrophilicity of the linker, and the like on the linker. Accordingly, the linker is preferably chosen to maximize the biological activity of the multibinding compound. The linker may be chosen to enhance the biological activity of the molecule. In general, the linker may be chosen from any organic molecule construct that orients two or more ligands to their ligand binding sites to permit multivalency. In this regard, the linker can be considered as a "framework" on which the ligands are arranged in order to bring about the desired ligand- orienting result, and thus produce a multibinding compound. For example, different orientations can be achieved by including in the framework groups containing mono- or polycyclic groups, including aryl and/or heteroaryl groups, or structures incoφorating one or more carbon-carbon multiple bonds (alkenyl, alkenylene, alkynyl or alkynylene groups). Other groups can also include oligomers and polymers which are branched- or - *τaight-chain species. In preferred embodiments, rigidity is imparted by the presence of cyclic groups (e.g., aryl, heteroaryl, cycloalkyl, heterocyclic, etc.). In other preferred embodiments, the ring is a six or ten member ring. In still further preferred embodiments, the ring is an aromatic ring such as, for example, phenyl or naphthyl. Different hydrophobic/hydrophilic characteristics of the linker as well as the presence or absence of charged moieties can readily be controlled by the skilled artisan. For example, the hydrophobic nature of a linker derived from hexamethylene diamine (H 2 N(CH 2 ) 6 NH 2 ) or related polyamines can be modified to be substantially more hydrophilic by replacing the alkylene group with a poly(oxyalkylene) group such as found in the commercially available "Jeffamines". By controlling the hydrophobicity/hydrophilicity of the linkers, the ability of the compounds to cross the blood/brain barrier can be controlled. This can be important when one wishes to maximize or minimize CNS effects. Examples of molecular structures in which the above bonding patterns could be employed as components of the linker are shown below. The identification of an appropriate framework geometry and size for ligand domain presentation are important steps in the construction of a multibinding compound with enhanced activity. Systematic spatial searching strategies can be used to aid in the identification of preferred frameworks through an iterative process. Core structures other than those shown here can be used for determining the optimal framework display orientation of the ligands. The process may require the use of multiple copies of the same central core structure or combinations of different types of display cores. The above-described process can be extended to trimers and compounds of higher valency. Assays of each of the individual compounds of a collection generated as described above will lead to a subset of compounds with the desired enhanced activities (e.g., potency, selectivity, etc.). The analysis of this subset using a technique such as Ensemble Molecular Dynamics will provide a framework orientation that favors the properties desired. A wide diversity of linkers is commercially available (see, e.g., Available Chemical Directory (ACD)). Many of the linkers that are suitable for use in this invention fall into this category. Other can be readily synthesized by methods well known in the art and/or are described below. Having selected a preferred framework geometry, the physical properties of the linker can be optimized by varying the chemical composition thereof. The composition of the linker can be varied in numerous ways to achieve the desired physical properties for the multibinding compound. For example, by adjusting the hydrophobicity or hydrophilicity of the linker, the ability of the compounds to cross the blood-brain barrier can be modified. It can therefore be seen that there is a plethora of possibilities for the composition of aTinker. Examples of linkers include aliphatic moieties, aromatic moieties, steroidal moieties, peptides, and the like. Specific examples are peptides or polyamides, hydrocarbons, aromatic groups, ethers, lipids, cationic or anionic groups, or a combination thereof. Examples are given below, but it should be understood that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. For example, properties of the linker can be modified by the addition or insertion of ancillary groups into or onto the linker, for example, to change the solubility of the multibinding compound (in water, fats, lipids, biological fluids, etc.), hydrophobicity, hydrophilicity, linker flexibility, antigenicity, stability, and the like. For example, the introduction of one or more poly(ethylene glycol) (PEG) groups onto or into the linker enhances the hydrophilicity and water solubility of the multibinding compound, increases both molecular weight and molecular size and, depending on the nature of the unPEGylated linker, may increase the in vivo retention time. Further PEG may decrease antigenicity and potentially enhances the overall rigidity of the linker. Ancillary groups which enhance the water solubility/hydrophilicity of the linker and, accordingly, the resulting multibinding compounds are useful in practicing this invention. Thus, it is within the scope of the present invention to use ancillary groups such as, for example, small repeating units of ethylene glycols, alcohols, polyols (e.g., glycerin, glycerol propoxylate, saccharides, including mono-, oligosaccharides, etc.), carboxylates (e.g., small repeating units of glutamic acid, acrylic acid, etc.), amines (e.g., tetraethylenepentamine), and the like) to enhance the water solubility and/or hydrophilicity of the multibinding compounds of this invention. In preferred embodiments, the ancillary group used to improve water solubility/hydrophilicity will be a polyether . The incoφoration of lipophilic ancillary groups within the structure of the linker to enhahce he lipophilicity and/or hydrophobicity of the multibinding compounds described herein is also within the scope of this invention. Lipophilic groups useful with the linkers of this invention include, by way of example only, aryl and heteroaryl groups which, as above, may be either unsubstituted or substituted with other groups, but are at least substituted with a group which allow s their covalent attachment to the linker. Other lipophilic groups useful with the linkers of this invention include fatty acid derivatives which do not form bilayers in aqueous medium until higher concentrations are reached. Also within the scope of this invention is the use of ancillary groups which result in the multibinding compound being incoφorated or anchored into a vesicle or other membranous structure such as a liposome or a micelle. The term "lipid" refers to any fatty acid derivative that is capable of forming a bilayer or a micelle such that a hydrophobic portion of the lipid material orients toward the bilayer while a hydrophilic portion orients toward the aqueous phase. Hydrophilic characteristics derive from the presence of phosphato, carboxylic, sulfato, amino, sulfhydryl, nitro and other like groups well known in the art. Hydrophobicity could be conferred by the inclusion of groups that include, but are not limited to, long chain saturated and unsaturated aliphatic hydrocarbon groups of up to 20 carbon atoms and such groups substituted by one or more aryl, heteroaryl, cycloalkyl, and or heterocyclic group(s). Prefened lipids are phosphglycerides and sphingolipids, representative examples of which include phosphatidylcholine, phosphatidylethanolamme, phosphatidylserine, phosphatidylinositol, phosphatidic acid, palmitoyleoyl phosphatidylcholine, lysophosphatidylcholine, lysophosphatidyl-ethanolamine, dipalmitoylphosphatidylcholine, dioleoylphosphatidylcholine, distearoyl-phosphatidylcholine or dilinoleoylphosphatidylcholine could be used. Other compounds lacking phosphorus, such as sphingolipid and glycosphingolipid families are also within the group designated as lipid. Additionally, the amphipathic lipids described above may be mixed with other lipids including triglycerides and sterols. The flexibility of the linker can be manipulated by the inclusion of ancillary groups which are bulky and/or rigid. The presence of bulky or rigid groups can hinder free rotation about bonds in the linker or bonds between the linker and the ancillary group(s) or bonds between the linker and the functional groups. Rigid groups can include, for example, those groups whose conformational lability is restrained by the presence of rings and/ or multiple bonds within the group, for example, aryl, heteroaryl, cycloalkyl, cycloalkenyl, and heterocyclic groups. Other groups which can impart rigidity include polypeptide groups such as oligo- or polyproline chains. Rigidity may also be imparted by internal hydrogen bonding or by hydrophobic collapse. Bulky groups can include, for example, large atoms, ions (e.g., iodine, sulfur, metal ions, etc.) or groups containing large atoms, polycyclic groups, including aromatic groups, non-aromatic groups and structures incoφorating one or more carbon-carbon multiple bonds (i.e., alkenes and alkynes). Bulky groups can also include oligomers and polymers which are branched- or straight-chain species. Species that are branched are expected to increase the rigidity of the structure more per unit molecular weight gain than are straight-chain species. In prefened embodiments, rigidity is imparted by the presence of cyclic groups (e.g., aryl, heteroaryl, cycloalkyl, heterocyclic, etc.). In other prefened embodiments, the linker comprises one or more six-membered rings. In still further prefened embodiments, the ring is an aryl group such as, for example, phenyl or naphthyl. Rigidity can also be imparted electrostatically. Thus, if the ancillary groups are either positively or negatively charged, the similarly charged ancillary groups will force the presenter linker into a configuration affording the maximum distance between each of the like charges. The energetic cost of bringing the like-charged groups closer to each other will tend to hold the linker in a configuration that maintains the separation between the like-charged ancillary groups. Further ancillary groups bearing opposite charges will tend to be attracted to their oppositely charged counteφarts and potentially may enter into both inter- and intramolecular ionic bonds. This non-covalent mechanism will tend to hold the linker into a conformation which allows bonding between the oppositely charged groups. The addition of ancillary groups which are charged, or alternatively, bear a latent charge when deprotected, following addition to the linker, including deprotection of a carboxyl, hydroxyl, thiol or amino group by a change in pH, oxidation, reduction or other mechanisms known to those skilled in the art which result in removal of the protecting group, is within the scope of this invention. In view of the above, it is apparent that the appropriate selection of a linker group providing suitable orientation, restricted/unrestricted rotation, the desired degree of hydrophobicity/hydrophilicity, etc. is well within the skill of the art. Eliminating or reducing antigenicity of the multibinding compounds described herein is also within the scope of this invention. In certain cases, the antigenicity of a multibinding compound may be eliminated or reduced by use of groups such as, for example, poly( ethylene glycol). As explained above, the multibinding compounds described herein comprise 2-10 ligands attached to a linker that links the ligands in such a manner that they are presented to the receptor for multivalent interactions with ligand binding sites thereon therein. The linker spatially constrains these interactions to occur within dimensions defined by the linker. This and other factors increases the biological activity of the multibinding compound as compared to the same number of ligands made available in monobinding form. The compounds of this invention are preferably represented by the empirical formula (L) p (X) q where L, X, p and q are as defined above. This is intended to include the several ways in which the ligands can be linked together in order to achieve the objective of multivalency, and a more detailed explanation is described below. As noted previously, the linker may be considered as a framework to which ligands are attached. Thus, it should be recognized that the ligands can be attached at any suitable position on this framework, for example, at the termini of a linear chain or at any intermediate position. The simplest and most prefened multibinding compound is a bivalent compound which can be represented as L-X-L, where each L is independently a ligand which may be the same or different and each X is independently the linker. Examples of such bivalent compounds are provided in Figure 12 where each shaded circle represents a ligand. A trivalent compound could also be represented in a linear fashion, i.e., as a sequence of repeated units L-X-L-X-L, in which L is a ligand and is the same or different at each occunence, as can X. However, a trimer can also be a radial multibinding compound comprising three ligands attached to a central core, and thus represented as (L) 3 X, where the linker X could include, for example, an aryl or cycloalkyl group. Illustrations of trivalent and tetravalent compounds of this invention are found in Figures 13 and 14 respectively where. again, the shaded circles represent ligands. Tetravalent compounds can be represented in a linear anay, e.g., L-X-L-X-L-X-L in a branched anay, e.g., L-X-L-X-L L (a branched construct analogous to the isomers of butane — ..-butyl, .so-butyl. sec- butyl, and t-butyl) or in a tetrahedral anay, e.g., where X and L are as defined herein. Alternatively, it could be represented as an alkyl, aryl or cycloalkyl derivative as above with four (4) ligands attached to the core linker. The same considerations apply to higher multibinding compounds of this invention containing 5-10 ligands, as illustrated in Figure 15. However, for multibinding agents attached to a central linker such as aryl or cycloalkyl, there is a self-evident constraint that there must be sufficient attac_._τιent sites on the linker to accommodate the number of ligands present; for example, a benzene ring could not directly accommodate more than 6 ligands, whereas a multi-ring linker (e.g., biphenyl) could accommodate a larger number of ligands. Certain of the above described compounds may alternatively be represented as cyclic chains of the form: X X ^X and variants thereof. All of the above variations are intended to be within the scope of the invention defined by the formula (L) p (X) q . With the foregoing in mind, prefened linkers may be represented by the following formulas: E -R b -E l (HI) wherein: R 6 is independently an alkyl, substituted alkyl, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenyl, substituted alkenyl, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, aryl, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, or oxyacylamino, for example. E x and E 2 are end groups that are capable of reacting with amino, hydroxy, halo, alkyl, or thiol containing groups on the ligands, or on precursors thereof, to form a linkage. Representative examples of the E l and E 2 end groups include, but are not limited to halogen, haloalkyl; carboxyl, carboxyalkyl, carbonyl, acyl, acyloxy, or halo-containing acyl. In one embodiment, the linker (X or X') comprises a covalent linkage and may not have the structure of Formula III above. Figures 5A-5C, 9 and 11 illustrates representative types of linkers for use in the present invention. Additionally, the linker moiety R 6 can be optionally substituted at any atom therein by one or more alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl, and heterocyclic groups. In view of the above description of the linker, it is understood that the term "linker" when used in combination with the term "multi-binding compound" includes both a covalently contiguous single linker (e.g., L-X-L), multiple covalently non-contiguous linkers (L-X-L-X-L) or no linker (e.g., -L-L-) within the multi-binding compound. Additionally, the linker moiety can be optionally substituted at any atom therein by one or more alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, substituted alkenyl, cycloalkenyl, substituted cycloalkenyl, alkynyl, substituted alkynyl, aryl, heteroaryl and heterocyclic group. In one embodiment of this invention, the linker (i.e., X or X') is selected from those shown in Table II: Table II Representative Linkers Linker -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 )-C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 2 -C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 3 -C(0)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH,) 4 -C(0)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 3 -C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 6 -C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 7 -C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 8 -C(O)-NH-(CH 2 ) --NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 9 -C(O)-NH-(CH 2 ) --NH- -H -(CH 2 ) 2 -NH-C(O)-(CH 2 ), 0 -C(O)-NH-(CH 2 ) 2 -NH- -H -(CH 2 ) 2 -NH-C(O)-(CH 2 ), ,-C(O)-NH-(CH 2 ) ,-NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ), 2 -C(O)-NH-(CH 2 ) 2 -NH- -H -(CH 2 ) 2 -NH-C(O)-Z-C(O)-NH-(CH 2 ) 2 -NH- where Z is 1,2-phenyl -HN-(CH 2 ) 2 -NH-C(O)-Z-C(0)-NH-(CH 2 ) 2 -NH- where Z is 1,3-phenyl -HN-(CH 2 ) 2 -NH-C(O)-Z-C(O)-NH-(CH 2 ) 2 -NH- where Z is 1,4-phenyl -HN-(CH 2 ) 2 -NH-C(O)-Z-O-Z-C(O)-NH-(CH 2 ) 2 -NH- where Z is 1,4-phenyl -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) ,-CH(NH-C(O)-(CH 2 ) 8 -CH 3 )-C(O)-NH-(CH^ NH- Linker -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 )-O-(CH 2 )-C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-Z-C(O)-NH-(CH 2 ) 2 -NH- where Z is 5-(«-octadecyloxy)-l,3-phenyl -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 2 -CH(NH-C(O)-Z)-C(O)-NH-(CH 2 ) 2 -NH- where Z is 4-biphenyl -HN-(CH 2 ) 2 -NH-C(O)-Z-C(O)-NH-(CH 2 ) 2 -NH- where Z is 5-(n-butyloxy)-l,3-phenyl -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 8 -trarø-(CH=CH)-C(O)-NH-(CH 2 ) 2 -NH- -H -(CH 2 ) 2 -NH-C(O)-(CH 2 ) ,-CH(NH-C(O)-(CH 7 ) -CH,)-C(0)-NH-(CH .),- NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 2 -CH(NH-C(O)-Z)-C(O)-NH-(CH 2 ) 2 -NH- where Z is 4-(n-octyl)-phenyl -HN-(CH 2 )-Z-O-(CH 2 ) 6 -O-Z-(CH 2 )-NH- where Z is 1,4-phenyl -HN-(CH 2 ) 2 -NH-C(O)-(CH.),-NH-C(O)-(CH,) 3 -C(O)-NH-(CH,) 1 -C(O)-NH- (CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 2 -CH(NH-C(O)-Ph)-C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH ,)-N+((CH 2 ) 9 -CH 3 )(CH 2 -C(O)-NH-(CH,) 2 -NH .)- (CH 2 )-C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 )-N((CH 2 ) 9 -CH 3 )-(CH 2 )-C(O)-NH-(CH 2 ) 2 -NH- -HN-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 2 -NH-C(O)-(CH 2 ) 2 -NH-C(O)-(CH.) 3 -C(O)-NH- (CH 2 ) 2 -C(O)-NH-(CH 2 ) 2 -C(O)-NH-(CH 2 ) 2 -NH- -HNr(CH 2 ) 2 ,KH-C(O)-Z-C(O)-NH-(CH 2 ) 2 -NH- where Z is 5-hydroxy-l,3-phenyl In another embodiment of this invention, the linker (i.e., X or X') has the formula: wherein each R a is independently selected from the group consisting of a covalent bond, alkylene, substituted alkylene and arylene; each R b is independently selected from the group consisting of hydrogen, alkyl and substituted alkyl; and ? ' is an integer ranging from 1 to about 20. The pharmacophore for the neurokinin antagonists was defined from the structural activity and mutagenesis studies of the amino ether based NK, antagonists developed by Merck. Four key features of the pharmacophore have been identified for the pharmacophore depicted below 6 : (1) There is an interaction with the protonated bridgehead nitrogen. (2) The benzhydryl group forms a key element of the structure for the high affinity NK, antagonists, however only one of the phenyl rings is necessary for binding to the receptor, with the second ring probably acting as a conformational anchor. (3) The His-197 forms an amino-aromatic interaction with one of the phenyl rings. (4) The Lys- 193 and Glu- 194 are in the binding pocket of the benzhydryl group. 6 Moreover, Gin- 165 may be involved where the heteroatom of the benzyl ether acts as a hydrogen bond acceptor, and a conformation of the benzyl ethers, in an edge- to-face aromatic-aromatic interaction, may access a lipophilic pocket containing His 265. Takeuchi, et al. 14 analyzed a structurally diverse set of Substance P antagonists to provide a pharmacophore hypothesis for the antagonist's receptor- bound conformation at the NK, receptor. In this conformation, two aromatic groups essential for high affinity adopt a peφendicular or edge-on anangement. lα Further, it was deduced that the non-peptide antagonist binding site in the human NK, receptor is defined by at least five residues in the fourth to seventh transmembrane segments, while the specific interactions with different antagonists can vary slightly within this region: His 197 in helix 5, His 265 in helix 6, Tyr 287 in helix 7, Gin 165 and Ser 169 in helix 4. " Based on the basic pharmacophore for NK, receptor ligands and the cunent available materials, several classes of multi-binding NK, ligands (compounds) can be prepared. The multi-binding NK, ligands are prefened because the NK, receptor is the most prevalent neurokinin receptor in mammals and plays a larger role in the mediation of the disorders or conditions mentioned above. Typically, such multi-binding compounds selected for use as a ligand will have at least one functional group, such as an amino, thiol, hydroxyl, halo or carboxyl group and the like, which allows the compound to be readily coupled to another ligand via a suitable linker. Compounds having such functionality are either known in the art or can be prepared by routine modification of known compounds using conventional reagents and procedures. The ligand can be covalently attached to the linker through any available position on the ligand, provided that when the ligand is attached to the linker, the ligand retains its ability to inhibit NK, agonists. Ligands Any compound which is an agonist, partial agonist, inverse agonist, partial inverse agonist or antagonist of the neurokinin receptors and which can be covalently linked to a linker as described herein can be used as a ligand in this invention. As discussed in further detail below, numerous such receptor agonists, partial agonists, inverse agonists, partial inverse agonists, and antagonists are known in the art and any of these known compounds or derivatives thereof may be employed as ligands in this invention. At least one, and preferably each, of the ligands L independently comprises the structure of Formula (A) below and illustrated in Figure 1 A: wherein: Z represents CH 2 B, NKB, NOB, =NB, =0, OB, SB, wherein: B represents H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y represents CUB, NB, NR, O, or S; R 1 represents B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen- containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A represents hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, or oxyacylamino; with the proviso that the compound includes one B moiety which is a direct link to the linker. In one embodiment, when the linker is linked to the ligand through a ring nitrogen or through the A or R groups, Z is CH 2 B, NHB, =NB, OB or SB, then B is alkaryl wherein the alkaryl comprises one or more substitutions on one or both of alkyl- and aryl- portions thereof, the substitutions comprising a R 2 R 3 substituted alkaryl or R 2 R 3 substituted alkyl-R 4 R ~ substituted aryl, wherein: R 2 and R 3 are individually selected from H, alkyl, substituted alkyl, alkylene, substituted alkylene, alkenyl, substituted alkenyl, alkoxy, substituted alkoxy, alkylalkoxy, acyl, acylamino, aminoacyl, acyloxy, carboxyalkyl or oxyacylamino; and R 4 and R 5 are individually selected from CF 3 , OCH 3 , OCF,, or a substituted nitrogen-containing heterocyclyl group; In another embodiment, the ligand is a ligand precursor and Z is OH, NOH or NHB, where B is H; Y is either O or CH 2 ; R 1 is H or an amino protecting group; and R is either H or oxo. As described below, ligand precursors may be linked together with a linker prior to completing the ligand synthesis. The prefened ligand L class comprises the structure of Formula (B) below and illustrated in Figure IB: R 2 R 1 (B) wherein: Z represents CH 2 , NB, NOH, NR, O, or S; B represents aryl, substituted aryl or a direct covalent link to the linker; A represents aryl, substituted aryl or a direct link to the linker; and Y, R, R 1 , R 2 and R 3 have the meanings defined above for the embodiments of formula (A). In a prefened embodiment of the prefened ligand class (Formula B), if A is substituted, it is substituted with a halogen or haloalkyl group; and in still another prefened embodiment, the aryl group in B has two substitutions comprising either the same or different ones of the following groups CF 3 , OCH , OCF 3 , or a substituted nitrogen-containing heterocyclyl group, for example, a substituted tetrazole (e.g. a trifluoromethyl tetrazole). Table 2 and Figure 2 illustrate examples of prefened monovalent ligands having the structure of Formulas (A) or (B) which are useful for the invention. The monovalent ligands of Table 2 have particular selectivity for the NK, receptor. Any compound which inhibits a neurokinin agonist ligand (e.g., SP, NKA, NKB) can be used as a ligand in this invention. As discussed in further detail below, numerous such neurokinin inhibitors are known in the art and any of these known compounds or derivatives thereof may be employed as ligands in this invention. Some of the known inhibitors are listed in Table 2 and are illustrated in Figure 2. Preferably, compounds that selectively inhibit NK, agonists are used as ligands for this invention. TABLE 2: Known Neurokinin Antagonists 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylethoxy)-3-(S)-(4- fluoro)phenyl-4-(3-oxo-l,2,4-triazol-5-yl-)methyl moφholine (MK-869) 19 ; 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl)phenylmethoxy)-3-(S)-(4- fluoro)phenyl-4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (LY-754-030) 10 ; N-[[2-methoxy-5-(trifluoromethoxy)phenyl]methyl]-2-phenyl-,(2S-cis)- 3- piperidinamine (CP-122721) 23 ; 2(S)-Phenyl-3(S)-(3,5-bis(trifluoromethyl) benzyl-oxy) piperidine (LY- 733-060) 17 ; 2(S)-((3,5-Bis(trifluoromethyl)benzyl)-oxy)-3(S)-phenyl-4-((3-oxo-1.2.4- triazol-5-yl)methyl)moφholine (L-742-694) 13 - 1720 N-[[2-methoxy-5-[5-(trifluoromethyl)-lH-tetrazol-l-yl]phenyl]methyl]-2- phenyl-3-piperidinamine (GW-205171) 23 ; and 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylmethoxy)-3-(S)-(4- fluoro)phenylmoφholine (LY-742-31 l) π ; Known ligand precursors 2-oxo-5-oximino-6-phenylpyridine; and N-BOC-2-hydroxy-3-(S)-phenylmoφholine. A prefened embodiment of multi -binding compounds are bivalent compounds having the Formula (I) which can be represented as L-X-L or L-L, where L is a ligand of Formulas (A) or (B) that is the same or different at each occunence, and X is the linker (or in one embodiment, a covalent linkage). Accordingly, examples of bivalent compounds of Formula I may be prepared as described below, with reference to Figures 4-11. It should be noted, however, that the same techniques can be used to generate higher order multi-binding compounds, i.e., the compounds of the invention where/, is 3-10. The substituent groups and linker components illustrated in Figures 4-1 1 have the same meanings as described above, unless otherwise specified. Preparation of Multibinding Compounds The multibinding compounds of this invention can be prepared from readily available starting materials using the following general methods and procedures. It will be appreciated that where typical or prefened process conditions (i.e., reaction temperatures, times, mole ratios of reactants, solvents, pressures, etc.) are given, other process conditions can also be used unless otherwise stated. Optimum reaction conditions may vary with the particular reactants or solvent used, but such conditions can be determined by one skilled in the art by routine optimization procedures. Additionally, as will be apparent to those skilled in the art, conventional protecting groups may be necessary to prevent certain functional groups from undergoing undesired reactions. The choice of a suitable protecting group for a particular functional group as well as suitable conditions for protection and deprotection are well known in the art. For example, numerous protecting groups, and their introduction and removal, are described in T. W. Greene and G. M. Wuts. Protecting Groups in Organic Synthesis, Second Edition, Wiley, New York, 1991, and references cited therein. The ligands can be covalently attached to the linker through any available position on the ligands, provided that when the ligands is attached to the linker (at least one of the linkers), the ligands retains its ability to bind to the neurokinin receptors. The term linker refers to everything that is not considered to be part of the ligand. Covalent linkage with the linkers can contribute to reducing the dose of the ligand required to induce the desired therapeutic effect. This may result from, for example, increased ability for the neurokinin receptors, in affinity may be caused, for example, by changing the ligand efficacy of the neurokinin receptors (from a partial to a full agonist) and/or by altering the reversibility of binding. By altering the reversibility of binding, the multivalent compounds described herein may result in a longer duration of action. Certain sites of attachment of the linker to the ligand are prefened based on known structure-activity relationships. Preferably, the linker is attached to a site on the ligand where structure-activity studies show that a wide variety of substituents are tolerated without loss of receptor activity. It will be understood by those skilled in the art that the following methods may be used to prepare other multibinding compounds of this invention. Ligand precursors, for example, ligands containing a leaving group or a nucleophilic group, can be covalently linked to a linker precursor containing a nucleophilic group or a leaving group, using conventional reagents and conditions. For example, two equivalents of ligand precursor with a halide, tosylate, or other leaving group, can be readily coupled to a linker precursor containing two nucleophilic groups, for example, amine groups, to form a dimer. The leaving group employed in this reaction may be any conventional leaving group including, by way of example, a halogen such as chloro, bromo or iodo, or a sulfonate group such as tosyl, mesyl and the like. When the nucleophilic group is a phenol, any base which effectively deprotonates the phenolic hydroxyl group may be used, including, by way of illustration, sodium carbonate, potassium carbonate, cesium carbonate, sodium hydride, sodium hydroxide, potassium hydroxide, sodium ethoxide, triethylamine, diisopropylethylamine and the like. Nucleophilic substitution reactions are typically conducted in an inert diluent, such as tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, 2- butanone, l-methyl-2-pyrrolidinone and the like. After the reaction is complete, the dimer is typically isolated using conventional procedures, such as extraction, filtration, chromatography and the like. By way of further illustration, dimers with a hydrophilic linker can be formed using a ligand precursor containing nucleophilic groups and a polyoxyethylene containing leaving groups, for example, poly(oxyethylene) dibromide (where the number of oxyethylene units is typically an integer from 1 to about 20). In this reaction, two molar equivalents of the ligand precursor are reacted with one molar equivalent of the poly(oxyethylene) dibromide in the presence of excess potassium carbonate to afford a dimer. This reaction is typically conducted in N,N-dimethylformamide at a temperature ranging from about 25°C to about 100°C for about 6 to about 48 hours. Alternatively, the linker connecting the ligands may be prepared in several steps. Specifically, a ligand precursor can first be coupled to an "adapter", i.e., a bifunctional group having a leaving group at one end and another functional group at the other end which allows the adapter to be coupled to a intermediate linker group. In some cases, the functional group used to couple to the intermediate linker is temporarily masked with a protecting group ("PG"). Representative examples of adapters include, by way of illustration, tert-butyl bromoacetate, 1- Fmoc-2-bromoethylamine, l-trityl-2-bromoethanethiol, 4-iodobenzyl bromide, propargyl bromide and the like. After the ligand precursor is coupled to the adapter and the protecting group is removed from the adapter's functional group (if a protecting group is present) to form an intermediate, two molar equivalents of the intermediate are then coupled with an intermediate linker to form a dimer. Ligand precursors can be coupled with adapters which include both leaving groups and protecting groups to form protected intermediates. The leaving group employed in this reaction may be any conventional leaving group including, by way of example, a halogen such as chloro, bromo or iodo, or a sulfonate group such as tosyl, mesyl and the like. Similarly, any conventional protecting group may be employed including, by way of example, esters such as the methyl, tert- butyl, benzyl ("Bn") and 9-fluorenylmethyl ("Fm") esters. Protected intermediates can then be deprotected using conventional procedures and reagents to afford deprotected intermediates. For example, tert- butyl esters are readily hydrolyzed with 95% trifluoroacetic acid in dichloromethane; methyl esters can be hydrolyzed with lithium hydroxide in tetrahydrofuran/water; benzyl esters can be removed by hydrogenolysis in the presence of a catalyst, such as palladium on carbon; and 9-fluorenylmethyl esters are readily cleaved using 20% piperidine in DMF. If desired, other well-known protecting groups and deprotecting procedures may be employed in these reactions to form deprotected intermediates. Similarly, ligand precursor having an adapter with an amine functional group can be prepared. Ligand precursors can be coupled with adapters which include leaving groups and protected amine groups to afford protected intermediates. The leaving group employed in this reaction may be any conventional leaving group. Similarly, any conventional amine protecting group may be employed including, by way of example, trityl, tert-butoxycarbonyl ("Boc"), benzyloxycarbonyl ("CBZ") and 9-fluorenylmethoxy-carbonyl ("Fmoc"). After coupling the adapter to the ligand precursor, the resulting protected intermediate is deprotected to afford a ligand precursor including an amine group using conventional procedures and reagents. For example, a trityl group is readily removed using hydrogen chloride in acetone; a Boc group is removed using 95% trifluoroacetic acid in dichloromethane; a CBZ group can be removed by hydrogenolysis in the presence of a catalyst, such as palladium on carbon; and a 9- fluorenylmethoxycarbonyl group is readily cleaved using 20% piperidine in DMF to afford the deblocked amine. Other well-known amine protecting groups and deprotecting procedures may be employed in these reactions to form amine- containing intermediates and related compounds. Ligand precursors having an adapter, for example, one including a free carboxylic acid group or a free amine group, can be readily coupled to intermediate linkers having complementary functional groups to form multibinding compounds as described herein. For example, when one component includes a carboxylic acid group, and the other includes an amine group, the coupling reaction typically employs a conventional peptide coupling reagent and is conducted under conventional coupling reaction conditions, typically in the presence of a trialkylamine, such as ethyldusopropylamine. Suitable coupling reagents for use in this reaction include, by way of example, carbodiimides, such as ethyl-3-(3- dimethylamino)propylcarbodiimide (EDC), dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC) and the like, and other well-known coupling reagents, such as N,N'-carbonyldiimidazole, 2-ethoxy-l-ethoxycarbonyl-l,2- dihydroquinoline (EEDQ), benzotriazol-1 -yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP), O-(7-azabenzotriazol-l-yl)-N,N,N',N'- tetramethyluronium hexafluorophosphate (HATU) and the like. Optionally, well- known coupling promoters, such N-hydroxysuccinimide, 1 -hydroxybenzotriazole (HOBT), 1 -hydroxy-7-azabenzotriazole (HO AT), N,N-dimethylaminopyridine (DMAP) and the like, may be employed in this reaction. Typically, this coupling reaction is conducted at a temperature ranging from about 0°C to about 60 °C for about 1 to about 72 hours in an inert diluent, such as THF, to afford the dimer. The multibinding compounds described herein can also be prepared using a wide variety of other synthetic reactions and reagents. For example, ligand precursors having ' aryliodide, carboxylic acid, amine and boronic acid functional groups can be prepared. Pyrroles can be readily coupled under Mitsunobu reaction conditions to various phenols to provide, after deprotection, functionalized intermediates. The Mitsunobu reaction is typically conducted by reacting hydroxymethyl pyrrole and the appropriate phenol using diethyl azodicarboxylate (DEAD) and triphenylphosphine at ambient temperature for about 48 hours. Deprotection, if necessary, using conventional procedures and reagents then affords the functionalized intermediates. The functionalized intermediates can be employed in the synthesis of multibinding compounds. For example, aryliodide intermediates can be coupled with bis-boronic acid linkers to provide dimers. Typically, this reaction is conducted by contacting two molar equivalents of the aryliodide and one molar equivalent of the bis-boronic acid in the presence of tetrakis(triphenylphosphine)palladium(0), sodium carbonate and water in refluxing toluene. Aryliodide intermediates can also be coupled with acrylate intermediates or alkyne intermediate to afford dimers. These reactions are typically conducted by contacting two molar equivalents of aryliodide intermediates with one molar equivalent of either acrylates or alkynes in the presence of dichlorobis(triphenylphosphine)palladium (II), copper (I) iodide and diisopropylethylamine in N,N-dimethylformamide to afford the respective dimers. As will be readily apparent to those of ordinary skill in the art, the synthetic procedures described herein or those known in the art may be readily modified to afford a wide variety of compounds within the scope of this invention. More specific methods for preparing the compounds of the present invention are described below. Ν-Ν Linkage (Type la) A first group of generic multi-binding ligands (21-24), prepared from the preferred generic ligand class of Formula (B), wherein R 1 is hydrogen, and a variety of generic linkers (5-8) for use in this invention are illustrated generally in Figure 4. The monovalent ligand (20) has an Ν-containing heterocyclyl (piperidinyl or moφholinyl) group. The monovalent ligands (20) are linked on either end of the R 6 linker (5-8) moiety (shown in Figure 4 as a shaded circle) via attachment through the basic nitrogen atom (Ν4) of the N-containing heterocyclyl (piperidinyl or moφholinyl) group to provide for N-N linked compounds of type la. The generic linkers illustrated in Figure 4 have E 1 and E~ representative end groups containing a halogen, carboxyl, carbonyl, or halocarbonyl, which react with the (N4) amino group on the N-containing heterocyclic group to replace the H at the R 1 position to form an acylamino (-NC(O)-) or cyano (-NC-) linkage with the linker. Specific examples of the preparation of multi-binding compounds of the invention having the N-N linkage of type la are described in Examples 1-3 in the Examples section below and illustrated in Figures 5A-5C. C3-C3 Linkage (Type lc) A second group of generic multi-binding ligands having the structure (41) illustrated in Figure 6A for use in this invention are prepared from a monovalent ligand (40) having the basic structure of formula (B) wherein A is a phenyl group with a halogen substitution thereon (an iodo substituent is shown in Figure 6A). The monovalent ligands (40) are attached together between the phenyl groups A at the C3 location on the N-containing heterocyclic (piperidinyl or moφholinyl) group to provide for C3-phenyl-phenyl-C3 linked compounds of type lc. The (-C- I-) bond in the monovalent ligand (40) is replaced with a (-C-C-) bond in the multi- binding compound (41). The phenyl A groups are linked in the para position. A specific example of the preparation of a multi-binding ligand compound having the C3-C3 linkage of type lc, is described in Example 4 in the Examples section below and illustrated in FIG. 6B and 7. Note that in this Example 4, the catalyst Pd(Ph 3 P) 4 does not form a part of the multi-binding compound (41a). The linked phenyl groups on the multi-binding compound are the A groups of (Formula (B)) on each of the monovalent ligands (40a). Therefore, for this embodiment, the multi-binding compound (41a) has the formula ( )p(X)q, where q is 0. C2-C2 Linkage (Type lb) A third group of generic multi-binding ligands (61, 81) and generic monovalent ligands (60, 80) and linkers (9, 10) for use in this invention are illustrated generally in Figures 8 and 10. The monovalent ligands (60, 80) have the basic structure of Formula (A), where Z is a hydroxyl group (60) or amino group (80). The linkers (9, 10), arbitrarily having either halogen or carbonyl E 1 and £ 2 end groups, react with the hydroxyl and amino Z groups to form alkoxy (-C-O-) and amino (-NHC-) linkages between the linker moiety and the Z groups of ligand 60 or 80, respectively. The Z groups are attached to the C2 position on the N- containing heterocyclic (piperidinyl or moφholinyl) group. As a result, the linker moieties R 6 are linked between the hydroxyl Z groups on monovalent ligands (60) and between the amino Z groups on monovalent ligand (80), respectively, at the C2 location on the N-containing heterocyclic (piperidinyl or moφholinyl) group to provide for C2- Z-R 6 -Z-C2 linked compounds of type lb. The synthesis of specific multi-binding compounds (61a, 81a), having the type lb linkage, are described in Examples 5 and 6 in the Examples section below and are illustrated in Figures 9 and 1 1. The sequence of synthesis steps for these specific multi-binding compounds (61a, 81a) in Examples 5 and 6 differ from the preparation of multi -binding compounds 21a, 22a, 23a and 41a in that the synthesis follows the steps of first linking precursor monovalent ligands together with the linkers, then modifying the subgroups, such as R 1 and the N-containing heterocyclic group; for example, after the linkage step to complete the synthesis of the multi-binding ligand. These Examples further illustrate the flexibility in the synthesis of the multi-binding compounds of the invention. Combinatorial Libraries The methods described herein lend themselves to combinatorial approaches for identifying multimeric compounds which possess multibinding properties. Specifically, factors such as the proper juxtaposition of the individual ligands of a multibinding compound with respect to the relevant array of binding sites on a target or targets is important in optimizing the interaction of the multibinding compound with its target(s) and to maximize the biological advantage through multivalency. One approach is to identify a library of candidate multibinding compounds with properties spanning the multibinding parameters that are relevant for a particular target. These parameters include: (1) the identity of ligand(s), (2) the orientation of ligands, (3) the valency of the construct, (4) linker length, (5) linker geometry, (6) linker physical properties, and (7) linker chemical functional groups. Libraries of multimeric compounds potentially possessing multibinding properties (i.e., candidate multibinding compounds) and comprising a multiplicity of such variables are prepared and these libraries are then evaluated via conventional assays conesponding to the ligand selected and the multibinding parameters desired. Considerations relevant to each of these variables are set forth below: Selection of Ligand(s) A single ligand or set of ligands is (are) selected for incoφoration into the libraries of candidate multibinding compounds which library is directed against a particular biological target or targets, i.e., binding to neurokinin receptors. The only requirement for the ligands chosen is that they are capable of interacting with the selected target(s). Thus, ligands may be known drugs, modified forms of known drugs, substructures of known drugs or substrates of modified forms of known drugs (which are competent to interact with the target), or other compounds. Ligands are preferably chosen based on known favorable properties that may be projected to be carried over to or amplified in multibinding forms. Favorable properties include demonstrated safety and efficacy in human patients, appropriate PK/ADME profiles, synthetic accessibility, and desirable physical properties such as solubility, logP, etc. However, it is crucial to note that ligands which display an unfavorable property from among the previous list may obtain a more favorable property through the process of multibinding compound formation; i.e., ligands should not necessarily be excluded on such a basis. For example, a ligand that is not sufficiently potent at a particular target so as to be efficacious in a human patient may become highly potent and efficacious when presented in multibinding form. A ligand that is potent and efficacious but not of utility because of a non-mechanism-related toxic side effect may have increased therapeutic index (increased potency relative to toxicity) as a multibinding compound. Compounds that exhibit short in vivo half-lives may have extended half-lives as multibinding compounds. Physical properties of ligands that limit their usefulness (e.g. poor bioavailability due to low solubility, hydrophobicity, hydrophilicity) may be rationally modulated in multibinding forms, providing compounds with physical properties consistent with the desired utility. Orientation: Selection of Ligand Attachment Points and Linking Chemistry Several points are chosen on each ligand at which to attach the ligand to the linker. The selected points on the ligand/linker for attachment are functionalized to contain complementary reactive functional groups. This permits probing the effects of presenting the ligands to their target binding site(s) in multiple relative orientations, an important multibinding design parameter. The only requirement for choosing attachment points is that attaching to at least one of these points does not abrogate activity of the ligand. Such points for attachment can be identified by structural information when available. For example, inspection of a co-crystal structure of a ligand bound to its target allows one to identify one or more sites where linker attachment will not preclude the ligand/target interaction. Alternatively, evaluation of ligand/target binding by nuclear magnetic resonance will permit the identification of sites non-essential for ligand/target binding. See, for example, Fesik, et al, U.S. Patent No. 5,891,643, the disclosure of which is incoφorated herein by reference in its entirety. When such structural information is not available, utilization of structure-activity relationships (SAR) for ligands will suggest positions where substantial structural variations are and are not allowed. In the absence of both structural and SAR information, a library is merely selected with multiple points of attachment to allow presentation of the ligand in multiple distinct orientations. Subsequent evaluation of this library will indicate what positions are suitable for attachment. It is important to emphasize that positions of attachment that do abrogate the activity of the monomeric ligand may also be advantageously included in candidate multibinding compounds in the library provided that such compounds bear at least one ligand attached in a manner which does not abrogate intrinsic activity. This selection derives from, for example, heterobivalent interactions within the context of a single target molecule. For example, consider a ligand bound to its target, and then consider modifying this ligand by attaching to it a second copy of the same ligand with a linker which allows the second ligand to interact with the same target at sites proximal to the first binding site, which include elements of the target that are not part of the formal ligand binding site and/or elements of the matrix sunounding the formal binding site, such as the membrane. Here, the most favorable orientation for interaction of the second ligand molecule may be achieved by attaching it to the linker at a position which abrogates activity of the ligand at the first binding site. Another way to consider this is that the SAR of individual ligands within the context of a multibinding structure is often different from the SAR of those same ligands in momomeric form. The foregoing discussion focused on bivalent interactions of dimeric compounds bearing two copies of the same ligand joined to a single linker through different attachment points, one of which may abrogate the binding/activity of the monomeric ligand. It should also be understood that bivalent advantage may also be attained with heterodimeric constructs bearing two different ligands that bind to common or different targets. Once the ligand attachment points have been chosen, one identifies the types of chemical linkages that are possible at those points. The most prefened types of chemical linkages are those that are compatible with the overall structure of the ligand (or protected forms of the ligand) readily and generally formed, stable and intrinsically innocuous under typical chemical and physiological conditions, and compatible with a large number of available linkers. Amide bonds, ethers. amines, carbamates, ureas, and sulfonamides are but a few examples of prefened linkages. Linker Selection In the library of linkers employed to generate the library of candidate multibinding compounds, the selection of linkers employed in this library of linkers takes into consideration the following factors: Valency: In most instances the library of linkers is initiated with divalent linkers. The choice of ligands and proper juxtaposition of two ligands relative to their binding sites permits such molecules to exhibit target binding affinities and specificities more than sufficient to confer biological advantage. Furthermore, divalent linkers or constructs are also typically of modest size such that they retain the desirable biodistribution properties of small molecules. Linker Length: Linkers are chosen in a range of lengths to allow the spanning of a range of inter-ligand distances that encompass the distance preferable for a given divalent interaction. In some instances the prefened distance can be estimated rather precisely from high-resolution structural information of targets. In other instances where high-resolution structural information is not available, one can make use of simple models to estimate the maximum distance between binding sites either on adjacent receptors or at different locations on the same receptor. In situations where two binding sites are present on the same target (or target subunit for multisubunit targets), prefened linker distances are 2-20 A, with more prefened linker distances of 3-12 A. In situations where two binding sites reside on separate target sites, prefened linker distances are 20-100 A, with more prefened distances of 30-70 A. Linker Geometry and Rigidity: The combination of ligand attachment site, linker length, linker geometry, and linker rigidity determine the possible ways in which the ligands of candidate multibinding compounds may be displayed in three dimensions and thereby presented to their binding sites. Linker geometry and rigidity are nominally determined by chemical composition and bonding pattern, which may be controlled and are systematically varied as another spanning function in a multibinding array. For example, linker geometry is varied by attaching two ligands to the ortho, meta, and para positions of a benzene ring, or in cis- or trαns-anangements at the 1,1- vs. 1,2- vs. 1,3- vs. 1,4- positions around a cyclohexane core or in cis- or tra«5-anangements at a point of ethylene unsaturation. Linker rigidity is varied by controlling the number and relative energies of different conformational states possible for the linker. For example, a divalent compound bearing two ligands joined by 1 ,8-octyl linker has many more degrees of freedom, and is therefore less rigid than a compound in which the two ligands are attacRed to the 4,4' positions of a biphenyl linker. Linker Physical Properties: The physical properties of linkers are nominally determined by the chemical constitution and bonding patterns of the linker, and linker physical properties impact the overall physical properties of the candidate multibinding compounds in which they are included. A range of linker compositions is typically selected to provide a range of physical properties (hydrophobicity, hydrophilicity, amphiphilicity, polarization, acidity, and basicity) in the candidate multibinding compounds. The particular choice of linker physical properties is made within the context of the physical properties of the ligands they join and preferably the goal is to generate molecules with favorable PK/ADME properties. For example, linkers can be selected to avoid those that are too hydrophilic or too hydrophobic to be readily absorbed and/or distributed in vivo. Linker Chemical Functional Groups: Linker chemical functional groups are selected to be compatible with the chemistry chosen to connect linkers to the ligands and to impart the range of physical properties sufficient to span initial examination of this parameter. Combinatorial Synthesis Having chosen a set of « ligands (n being determined by the sum of the number of different attachment points for each ligand chosen) and m linkers by the process outlined above, a library of (n\)m candidate divalent multibinding compounds is prepared which spans the relevant multibinding design parameters for a particular target. For example, an anay generated from two ligands, one which has two attachment points (Al, A2) and one which has three attachment points (Bl, B2, B3) joined in all possible combinations provide for at least 15 possible combinations of multibinding compounds: Al-Al A1-A2 Al-Bl A1-B2 A1-B3 A2-A2 A2-B1 A2-B2 A2-B? • Bl÷Bl B1-B2 B1-B3 B2-B2 B2-B3 B3-B3 When each of these combinations is joined by 10 different linkers, a library of 150 candidate multibinding compounds results. Given the combinatorial nature of the library, common chemistries are preferably used to join the reactive functionalies on the ligands with complementary reactive functionalities on the linkers. The library therefore lends itself to efficient parallel synthetic methods. The combinatorial library can employ solid phase chemistries well known in the art wherein the ligand and/or linker is attached to a solid support. Alternatively and preferably, the combinatorial libary is prepared in the solution phase. After synthesis, candidate multibinding compounds are optionally purified before assaying for activity by, for example, chromatographic methods (e.g., HPLC). Analysis of the Library Various methods are used to characterize the properties and activities of the candidate multibinding compounds in the library to detei ine which compounds possess multibinding properties. Physical constants such as solubility under various solvent conditions and logD/clogD values can be determined. A combination of NMR spectroscopy and computational methods is used to determine low-energy conformations of the candidate multibinding compounds in fluid media. The ability of the members of the library to bind to the desired target and other targets is determined by various standard methods, which include radioligand displacement assays for receptor and ion channel targets, and kinetic inhibition analysis for many enzyme targets. In vitro efficacy, such as for receptor agonists and antagonists, ion channel blockers, and antimicrobial activity, can also be determined. Pharmacological data, including oral absoφtion, everted gut penetration, other pharmacokinetic parameters and efficacy data can be determined in appropriate models. In this way, key structure-activity relationships are obtained for multibinding design parameters which are then used to direct future work. The members of the library which exhibit multibinding properties, as defined herein, can be readily determined by conventional methods. First those members which exhibit multibinding properties are identified by conventional methods as described above including conventional assays (both in vitro and in vivo). Second, ascertaining the structure of those compounds which exhibit multibinding properties can be accomplished via art recognized procedures. For example, each member of the library can be encrypted or tagged with appropriate information allowing determination of the structure of relevant members at a later time. See, for example, Dower, et al., International Patent Application Publication No. WO 93/06121; Brenner, et al., Proc. Natl. Acad. Sci., USA, 89:5181 (1992); Gallop, et al., U.S. Patent No. 5,846,839; each of which are incoφorated herein by reference in its entirety. Alternatively, the structure of relevant multivalent compounds can also be determined from soluble and untagged libaries of candidate multivalent compounds by methods known in the art such as those described by Hindsgaul, et al., Canadian Patent Application No. 2,240,325 which was published on July 11, 1998. Such methods couple frontal affinity chromatography with mass spectroscopy to determine both the structure and relative binding affinities of candidate multibinding compounds to receptors. The process set forth above for dimeric candidate multibinding compounds can, of course, be extended to trimeric candidate compounds and higher analogs thereof. Follow-up Synthesis and Analysis of Additional Libraries Based on the information obtained through analysis of the initial library, an optional component of the process is to ascertain one or more promising multibinding "lead" compounds as defined by particular relative ligand orientations, linker lengths, linker geometries, etc. Additional libraries can then be generated around these leads to provide for further information regarding structure to activity relationships. These arrays typically bear more focused variations in linker structure in an effort to further optimize target affinity and/or activity at the target (antagonism, partial agonism, etc.), and/or alter physical properties. By iterative redesign/analysis using the novel principles of multibinding design along with classical medicinal chemistry, biochemistry, and pharmacology approaches, one is able to prepare and identify optimal multibinding compounds that exhibit biological advantages towards their targets and as therapeutic agents. To further elaborate upon this procedure, suitable divalent linkers include, by way of example only, those derived from dicarboxylic acids, disulfonylhalides, dialdehydes, diketones, dihalides, diisocyanates, diamines, diols, mixtures of carboxylic acids, sulfonylhalides, aldehydes, ketones, halides, isocyanates, amines and diols. In each case, the carboxylic acid, sulfonylhalide, aldehyde, ketone, halide, isocyanate, amine and diol functional group is reacted with a complementary functionality on the ligand to form a covalent linkage. Such complementary functionality is well known in the art. Exemplary linkers include the following linkers identified as X-l through X-418 as set forth below: ιe_.π/66sn/iDci 000*9/66 OΛV Pharmaceutical Fotmulations When employed as pharmaceuticals, the compounds of this invention are usually administered in the form of pharmaceutical compositions. These compounds can be administered by a variety of routes including oral, rectal, transdermal, subcutaneous, intravenous, intramuscular, and intranasal. These compounds are effective as both injectable and oral compositions. Such compositions are prepared in a manner well known in the pharmaceutical art and comprise at least one active compound. Preferred compounds are those which have receptor binding activity toward one or more neurokinin receptors at concentrations of less than 1 mM. This invention also includes pharmaceutical compositions which contain, as the active ingredient, one or more of the compounds described herein associated with pharmaceutically acceptable carriers. In making the compositions of this invention, the active ingredient is usually mixed with an excipient, diluted by an excipient or enclosed within such a carrier which can be in the form of a capsule, sachet, paper or other container. When the excipient serves as a diluent, it can be a solid, semi-solid, or liquid material, which acts as a vehicle, carrier or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments containing, for example, up to 10% by weight of the active compound, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders. In preparing a formulation, it may be necessary to mill the active compound to provide the appropriate particle size prior to combining with the other ingredients. If the active compound is substantially insoluble, it ordinarily is milled to a particle size of less than 200 mesh. If the active compound is substantially water soluble, the particle size is normally adjusted by milling to provide a substantially uniform distribution in the formulation, e.g., about 40 mesh. Some examples of suitable excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, sterile water, syrup, and methyl cellulose. The formulations can additionally include: lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying and suspending agents; preserving agents such as methyl- and propylhydroxy-benzoates; sweetening agents; and flavoring agents. The compositions of the invention can be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art. The compositions are preferably formulated in a unit dosage form, each dosage containing from about 0.001 to about 1 g, preferably between about 5 to about 100 mg, more preferably between about 10 to about 30 mg, of the active ingredient. The term "unit dosage forms" refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each-writ containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient. Preferably, the compound of formula I above is employed at no more than about 20 weight percent of the pharmaceutical composition, more preferably no more than about 15 weight percent, with the balance being pharmaceutically inert carrier(s). The active compound is effective over a wide dosage range and is generally administered in a pharmaceutically effective amount. It, will be understood, however, that the amount of the compound actually administered will be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered and its relative activity, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical excipient to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This solid preformulation is then subdivided into unit dosage forms of the type described above containing from, for example, 0.1 to about 500 mg of the active ingredient of the present invention. The tablets or pills of the present invention may be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permit the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol, and cellulose acetate. The liquid forms in which the novel compositions of the present invention may be incorporated for administration orally or by injection include aqueous solutions, suitably flavored syrups, aqueous or oil suspensions, and flavored emulsions with edible oils such as corn oil, cottonseed oil, sesame oil, coconut oil, or peanut oil, as well as elixirs and similar pharmaceutical vehicles. Compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable, aqueous or organic solvents, or mixtures thereof, and powders. The liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as described supra. Preferably the compositions are administered by the oral or nasal respiratory route for local or systemic effect. Compositions in preferably pharmace itically acceptable solvents may be nebulized by use of inert gases. Nebulized solutions may be inhaled directly from the nebulizing device or the nebulizing device may be attached to a face mask tent, or intermittent positive pressure breathing machine. Solution, suspension, or powder compositions may be administered, preferably orally or nasally, from devices which deliver the formulation in an appropriate manner. The following formulation examples illustrate representative pharmaceutical compositions of the present invention. Formulation Example 1 Hard gelatin capsules containing the following ingredients are prepared: Quantity Ingredient (mg/capsule) Active Ingredient 30.0 Starch 305.0 Magnesium stearate 5.0 The above ingredients are mixed and filled into hard gelatin capsules in 340 mg quantities. Formulation Example..2 A tablet formula is prepared using the ingredients below: Quantity Ingredient (mg/tablet) Active Ingredient 25.0 Cellulose, microcrystalline 200.0 Colloidal silicon dioxide 10.0 Stearic acid 5.0 The components are blended and compressed to form tablets, each weighing 240 mg. Formulation Example 3 A dry powder inhaler formulation is prepared containing the following components: Ingredient Weight % Active Ingredient 5 Lactose 95 The active ingredient is mixed with the lactose and the mixture is added to a dry powder inhaling appliance. Formulation Example 4 Tablets, each containing 30 mg of active ingredient, are prepared as follows: Quantity Ingredient (mg/tablet) Active Ingredient 30.0 mg Starch 45.0 mg Microcrystalline cellulose 35.0 mg Polyvinylpyrrolidone (as 10% solution in sterile water) 4.0 mg Sodium carboxymethyl starch 4.5 mg Magnesium stearate 0.5 mg Talc 1 .0 mg Total 120 mg The active ingredient, starch and cellulose are passed through a No. 20 mesh U.S. sieve and mixed thoroughly. The solution of polyvinylpyrrolidone is mixed with the resultant powders, which are then passed through a 16 mesh U.S. sieve. The granules so produced are dried at 50° to 60 C C and passed through a 16 mesh U.S. sieve. The sodium carboxymethyl starch, magnesium stearate, and talc, previously passed through a No. 30 mesh U.S. sieve, are then added to the granules which, after mixing, are compressed on a tablet machine to yield tablets each weighing 120 mg. Formulation Example 5 Capsules, each containing 40 mg of medicament are made as follows: Quantity Ingredient (mg/capsule) Active Ingredient 40.0 mg • Starch 109.0 mg Magnesium stearate 1.0 mg Total 150.0 mg The active ingredient, starch, and magnesium stearate are blended, passed through a No. 20 mesh U.S. sieve, and filled into hard gelatin capsules in 150 mg quantities. Formulation Example 6 Suppositories, each containing 25 mg of active ingredient are made as follows: Ingredient Amount Active Ingredient 25 mg Saturated fatty acid glycerides to 2,000 mg The active ingredient is passed through a No. 60 mesh U.S. sieve and suspended in the saturated fatty acid glycerides previously melted using the minimum heat necessary. The mixture is then poured into a suppository mold of nominal 2.0 g capacity and allowed to cool. Formulation Example 7 Suspensions, each containing 50 mg of medicament per 5.0 mL dose are made as follows: Ingredient Δ_________nt Active Ingredient 50.0 mg Xanthan gum 4.0 mg Sodium carboxymethyl cellulose (11%) Microcrystalline cellulose (89%) 50.0 mg Sucrose 1.75 g Sodium benzoate 10.0 mg Flavor and Color q.v. Purified water to 5.0 mL The active ingredient, sucrose and xanthan gum are blended, passed through a No. 10 mesh U.S. sieve, and then mixed with a previously made solution of the microcrystalline cellulose and sodium carboxymethyl cellulose in water. The sodium benzoate, flavor, and color are diluted with some of the water and added with stirring. Sufficient water is then added to produce the required volume. Formulation Example 8 A formulation may be prepared as follows: Quantity Ingredient (mg/capsule) Active Ingredient 15.0 mg Starch 407.0 mg Magnesium stearate 3.0 mg Total 425.0 mg The active ingredient, starch, and magnesium stearate are blended, passed through a No. 20 mesh U.S. sieve, and filled into hard gelatin capsules in 425.0 mg quantities. Formulation Example 9 A formulation may be prepared as follows: Ingredient Quantity Active Ingredient 5.0 mg Corn Oil 1.0 mL Formulation Example 1 A topical formulation may be prepared as follows: Ingredient Quantity Active Ingredient 1 - 10 g Emulsifying Wax 30 g Liquid Paraffin 20 g White Soft Paraffin to 100 g The white soft paraffin is heated until molten. The liquid paraffin and emulsifying wax are incorporated and stirred until dissolved. The active ingredient is added and stirring is continued until dispersed. The mixture is then cooled until solid. Another preferred formulation employed in the methods of the present invention employs transdermal delivery devices ("patches"). Such transdermal patches may be used to provide continuous or discontinuous infusion of the compounds of the present invention in controlled amounts. The construction and use of transdermal patches for the delivery of pharmaceutical agents is well known in the art. See, e.g., U.S. Patent 5,023,252, issued June 1 1, 1991, herein incorporated by reference in its entirety. Such patches may be constructed for continuous, " pulsatile, or on demand delivery of pharmaceutical agents. Other suitable formulations for use in the present invention can be found in Remington's Pharmaceutical Sciences, Mace Publishing Company, Philadelphia, PA, 17th ed. ( 1985). Utility The compounds of this invention modulate neurokinin receptor activity and accordingly, may be used for the treatment of, or inhibiting the symptoms of, Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthritis, pain, chronic pain, migraine headaches, asthma, bronchitis, irritable bowel syndrome, allergic rhinitis, osteoarthritis, cystitis, and emesis, especially chemotherapy induced emesis in mammals. More particularly the compounds may be used in the treatment of medical and veterinary conditions in mammals. The compounds of this invention preferably selectively modulate the NK, receptor activity. The compounds of the invention are particularly useful in treating the above disorders mediated in one form or another by neurokinin receptor activity. Accordingly, the invention also relates to pharmaceutical composition comprising a pharmaceutically acceptable excipient and an effective amount of a compound of the invention. When used in treating or ameliorating such conditions, the compounds of this invention are typically delivered to a patient in need of such treatment by a pharmaceutical composition comprising a pharmaceutically acceptable diluent and an effective amount of at least one compound of this invention. The amount of compound administered to the patient will vary depending upon what compound and/or composition is being administered, the purpose of the administration, such as prophylaxis or therapy, the state of the patient, the manner of administration, and the like. In therapeutic applications, compositions are administered to a patient already suffering from, for example, emesis, in an amount sufficient to at least partially reduce the symptoms. Amounts effective for this use will depend on the judgment of the attending clinician depending upon factors such as the degree or severity of the disorder in the patient, the age, weight and general condition of the patient, and the like. The pharmaceutical compositions of this invention may contain more than one compound of the present invention. As noted above, the compounds administered to a patient are in the form of pharmaceutical compositions described above which can be administered by a variety of routes including oral, rectal, transdermal, subcutaneous, intravenous, intramuscular, etc. These compounds are effective as both injectable and oral deliverable pharmaceutical compositions. Such compositions are prepared in a manner well known in the pharmaceutical art and comprise at least one active compound. The multibinding compounds of this invention can also be administered in the form of pro-drugs, i.e., as derivatives which are converted into a biologically active compound in vivo. Such pro-drugs will typically include compounds in which, for example, a carboxylic acid group, a hydroxyl group or a thiol group is converted to a biologically liable group, such as an ester, lactone or thioester group which will hydrolyze in vivo to reinstate the respective group. The compounds can be assayed to identify which of the multimeric ligand compounds possess multibinding properties. First, one identifies a ligand or mixture of ligands which each contain at least one reactive functionality and a library of linkers which each include at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand. Next, one prepares a multimeric ligand compound library by combining at least two stoichiometric equivalents of the ligand or mixture of ligands with the library of linkers under conditions wherein the complementary functional groups react to form a covalent linkage between the linker and at least two of the ligands. The multimeric ligand compounds produced in the library can be assayed to identify multimeric ligand compounds which possess multibinding properties. The method can also be performed using a library of ligands and a linker or mixture of linkers. The preparation of the multimeric ligand compound library can be achieved by either the sequential or concurrent combination of the two or more stoichiometric equivalents of the ligands with the linkers. The multimeric ligand compounds can be dimeric, for example, homomeric or heteromeric. A heteromeric ligand compound library can be prepared by sequentially adding a first and second ligand. Each member of the multimeric ligand compound library can be isolated from the library, for example, by preparative liquid chromatography mass spectrometry (LCMS). The linker or linkers can be flexible linkers, rigid linkers, hydrophobic linkers, hydrophilic linkers, linkers of different geometry, acidic linkers, basic linkers, linkers of different polarization and/or polarizability or amphiphilic linkers. The linkers can include linkers of different chain lengths and/or which have different complementary reactive groups. In one embodiment, the linkers are selected to have different linker lengths ranging from about 2 to 100A. The ligand or mixture of ligands can have reactive functionality at different sites on the ligands. The reactive functionality can be, for example, carboxylic acids, carboxylic acid halides, carboxyl esters, amines, halides, pseudohalides, isocyanates, vinyl unsaturation, ketones, aldehydes, thiols, alcohols, anhydrides, boronates, and precursors thereof, as long as the reactive functionality on the ligand is complementary to at least one of the reactive groups on the linker so that a covalent linkage can be formed between the linker and.the ligand. A library of multimeric ligand compounds can thus be formed which possesses multivalent properties. Multimeric ligand compounds possessing multibinding properties can be identified in an iterative method by preparing a first collection or iteration of multimeric compounds by contacting at least two stoichiometric equivalents of the ligand or mixture of ligands which target the neurokinin receptors with a linker or mixture of linkers, where the ligand or mixture of ligands includes at least one reactive functionality and the linker or mixture of linkers includes at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand. The ligand(s) and linker(s) are reacted under conditions which form a covalent linkage between the linker and at least two of the ligands. The first collection or iteration of multimeric compounds can be assayed to assess which if any of the compounds possess multibinding properties. The process can be repeated until at least one multimeric compound is found to possess multibinding properties. By evaluating me particular molecular constraints which are imparted or are consistent with imparting multibinding properties to the multimeric compound or compounds in the first iteration, a second collection or iteration of multimeric compounds which elaborates upon the particular molecular constraints can be assayed, and the steps optionally repeated to further elaborate upon said molecular constraints. For example, the steps can be repeated from between 2 and 50 times, more preferably, between 5 and 50 times. In order to further illustrate the present invention and advantages thereof, the following specific examples are given but are not meant to limit the scope of the claims in any way. Unless otherwise stated, all temperatures are in degrees Celsius. EXAMPLES Examples 1 - 6 are provided as representative examples of methods for preparing compounds of this invention. In the examples below, the following abbreviations have the following meanings. If an abbreviation is not defined, it has its generally accepted meaning. A = Angstroms cm = centimeter DIC = 2-dimethylaminoisopropyl chloride hydrochloride DCC = N,N-dicyclohexylcarbodiimide DCM = dichloromethane DIPEA diisopropylethylamine DMA = N,N-dimethylacetamide DMAP = -N,N-dimethylam_nopyridine DMF = N,N-dimethylformamide DMSO = dimethylsulfoxide DPPA = diphenylphosphoryl azide g gram HBTU = 1-hydroxybenzotrizole HPLC = high performance liquid chromatography Hunig's base = diisopropylethylamine MFC = minimum fungicidal concentration mg milligram MIC = minimum inhibitory concentration min = minute mL milliliter mm = millimeter mmol millimol N normal PyBOP pyridine benzotriazol- 1 -yloxy-tris(dimethyl- amino)phosphonium hexafluorophosphate t-BOC tert-butyloxycarbonyl TBAF = tetrabutyl ammonium fluoride TFA = trifluoroacetic acid THF = tetrahydrofuran μL microliters EDTA ethylenediaminetetraacetic acid MEM minimal essential medium μm microns Syntheses of Bivalent Neurokinin Receptor Antagonists Based on the basic pharmacophore for neurokinin receptor antagonists and the current available materials, several classes of bivalent neurokinin receptor antagonists are designed, the syntheses are described in the following six examples. N-N Linked Compounds (Type la Linkage) Example 1 Bivalent compound (21a) is made from monovalent ligands (20a) having the structure of Formula (A) wherein A is H; Y is O; R is H; R 1 is H; Z is OB, wherein B is an alkaryl, preferably a R 2 , R 3 disubstituted methyl-R 4 , R 5 di-substituted phenyl; R 2 and R 3 are both H; and R and R 5 are both -CF 3 . Similarly, the monovalent ligand (20a) has the basic structure of preferred Formula (B), wherein Z is oxygen, B is a substituted aryl, having a preferred aryl di-substitution of trifluoromethyl groups, A is an unsubstituted aryl group, and Y, R 1 , R 2 and R 3 have the meanings defined above for Formula (A). The monovalent ligands (20a) are linked via their moφholinyl (Y=O) nitrogen (N4) positions using a linker (5a) comprising a di-substituted alkyl, such as di- aldehyde butane. Compound (21a) may be prepared as shown in Figure 5 A and as described below. Figure 5 A illustrates the chemical synthesis of a multi-binding ligand compound (21a) of the present invention from the monovalent ligand compound (20a). Under a nitrogen atmosphere, 5.00 mmols of 20a and 2.5 mmols of linker 1,4-dibromobutane (5a) are dissolved in ethanol in a sealed tube. DIPEA (2.75 mmols) is added, and the reaction is refluxed for 12 hours. The reaction is concentrated and the crude product is purified by silica-gel chromatography (MeOH/CH 2 Cl 2 ). ' After concentration of the product-containing fractions, the product is dissolved in methanol and 4 N HCI is added until the pH is between 1 and 2. The solution is stirred for 20 minutes and then pipetted into ether to precipitate the product as its dihydrochloride salt, which is then filtered and dried to yield the title product. The monovalent ligand, compound (20a), is described in EP-00577394 and generally represents monovalent ligand LY-742-311 of Table 2 and Figure 2, except without a methyl group on R 2 . Example 2 Bivalent compound (22a) is made from monovalent ligands (20b) having the basic structure of Formula (A), wherein A is H; Y is CH 2 ; R is H; R 1 is H; Z is -NHB, wherein B is -R 2 , R 3 di-substituted methyl-R 4 , R 5 di-substituted phenyl; R 2 and R 3 are both H; R 4 is -OCH 3 and R 5 is -OCF 3 . Similarly, monovalent ligands (20b) have the basic structure of preferred Formula (B) wherein Z is -NH, A is an unsubstituted aryl, B is a di-substituted aryl, wherein the di-substitution is -OCH and -OCF 3 and Y, R 1 , R 2 and R 3 have the same definition as given above for ligand (20b) of Formula (A). The monovalent ligands (20b) are linked via their piperidyl (Y=CH 2 ) nitrogen (N4) positions using a linker (6a) comprising a di- carboxyl substituted benzene, such as benzene- 1,4-bisacetic acid. Compound (22a) may be prepared as shown in Figure 5B and as described below. Figure 5B illustrates the chemical synthesis of a multi-binding ligand compound (22a) of the present invention from the monovalent ligand compound (20b). A solution of ligand 20b (2 mmols) and benzene- 1,4-bisacetic acid linker 6a (lmmol) in methylene chloride is prepared under argon in a flask equipped with magnetic stirrer and drying tube. To this solution is added dicyclohexylcarbodiimide (solid, 2.1 mmols) while stirring at room temperature. The course of the reaction is followed by thin layer chromatography. When reaction has occurred, the reaction solution is diluted with ethyl acetate and washed with water and with aqueous Na 2 CO 3 . The organic layer is dried (Na j SO,,), filtered and concentrated under reduced pressure to give the crude product. The desired compound is obtained by purification of the crude product by use of HPLC. The monovalent ligand, compound (20b), is described in WO- 0930031 and represents monovalent compound CP-122721 of Table 2 and Figure 2. Example 3 Bivalent compound (23a) is made from monovalent ligands (20c) having a basic structure of the Formula (A) wherein A is H; Y is CH 2 ; R is H; R 1 is H; Z is -NHB, wherein B is R 2 , R 3 di-substituted methyl-R 4 , R 5 di-substituted phenyl; R 2 and R 3 are both H; R 4 is -OCH 3 and R 5 is 5-(2-trifluoromethyl)tetrazole. Similarly, monovalent ligand (20c) has the basic structure of preferred Formula (B), wherein Z is NH, A is an unsubstituted aryl, B is a di-substituted aryl, where the substitutions are -OCH 3 and 5-(2-trifluoromethyl) tetrazole and Y, R 1 , R 2 and R 3 have the definitions as provided above for the Formula (A) ligands (20c). The monovalent ligands (20c) are linked via their piperidyl (Y=O) nitrogen (N4) positions using a linker (7a) comprising ethyldioxy-dialdehyde. The ethyldioxy R 6 moiety becomes a part of the multi-binding compound (23a) in accordance with the invention. Compound (23a) may be prepared as shown in Figure 5C and as described below. Figure 5C illustrates the chemical synthesis of a multi-binding ligand compound (23a) of the present invention from the monovalent ligand compound (20c). Compound (20c) (2 mmol) is dissolved in CHC1 3 . Acetic acid is then added and the reaction is heated to reflux. An ethyl di-oxy di-aldehyde linker (7a) (1 mmol) dissolved in CH 2 C1 2 is then added dropwise to the refluxing solution over 60 minutes and the reaction is refluxed for an additional 60 minutes. At this point, NaBH(OAc) 3 (OAc=acetate) is added in portions and the reaction is stirred at reflux for an additional 2 hours. The reaction is allowed to cool and is then quenched with aqueous NH 4 C1 solution until the pH of the solution is adjusted to pH 7.0 using either 1 M HCI or 1 M NaOH. The product is extracted from this aqueous phase with ethyl acetate. The organic layer is dried using Na^SO.^ The drying agent is then filtered off and the solvent is removed in vacuo to provide the crude product. The desired material is purified from this mixture using reverse phase HPLC. The monovalent ligand, compound (20c), is described in WO- 09508549 and represents monovalent ligand GW 205171 of Table 2 and Figure 2. C3-C3 Linked Compounds (Type lc) Example 4 Bivalent compound (41a) is made from monovalent ligands (40a) having the basic structure of Formula (A), wherein A is a halogen; Y is O; R is H; R 1 is 2,3- dihydro-3-oxo-l,2,4-triazol-5-ylmethyl; Z is -OB, wherein B is -R 2 , R 3 disubstituted methyl-R 4 , R 5 di-substituted phenyl; R 2 and R 3 are both H; R 4 and R 5 are both -CF 3 . Similarly, the monovalent ligands (40a) have the preferred structure of Formula (B), wherein Z is O, B is 3,5-trifluoromethylphenyl, A is .αra-iodophenyl, and Y, R 1 , R 2 and R 3 have the definitions as provided above for the Formula (A) ligands (40a). The monovalent ligands (40a) are linked via the aryl A substitutions on their moφholino (Y^O) C3 positions at the para location using Pd(Ph 3 P) 4 . Although similar to known monovalent ligand LY-754-030 of Table 2 and Figure 2, except for the iodo-substitution instead of a fluoro group, the monovalent ligand (40a) had to be prepared from precursor materials for this invention. Figure 7 illustrates the synthesis of the monovalent ligand (40a). Figure 6B illustrates the synthesis of bivalent compound (41a) from monovalent ligand (40a) and both syntheses are described below. Figure 6B illustrates the chemical synthesis of a multi-binding ligand compound (41a) of the present invention from the monovalent ligand compound (40a). To a solution of monovalent ligand (40a) (1.0 mmol) in 4.0 mL of DMF is added catalytic Pd°(Ph 3 P) 4 (0.1 mmol), triethylamine (NEt 3 ) (2.0 mmol) and Cul (1.0 mmol). The reaction mixture is heated at 90°C for 12 hours. The reaction mixture is allowed to cool, and is then partitioned between ethyl acetate and saturated NaHCO 3 and the layers are separated. The aqueous layer is extracted with ethyl acetate; the organic extracts are combined, dried and concentrated in vacuo. The product is purified by chromatography. Note that in this embodiment, the linker is replaced by a covalent linkage, which does not form a part of the multi-binding compound (41a). The linked phenyl groups on the multi-binding compound are the A groups of (Formula (B)) on each of the monovalent ligands (40a). Therefore, for this embodiment, the multi -binding compound (41a) has the formula (L)p(X)q, where q is 0. As stated above, the monovalent ligand (40a) having dtparo-xoάo substitution on the A group was not known to exist. Therefore, ligand (40a) had to be synthesized from precursor materials. Figure 7 illustrates the reaction scheme for preparing the monovalent compound (40a) from precursor starting materials in accordance with one embodiment of the invention. First, a precursor ligand material (35), N-BOC-3-(S)-(4-iodophenyl)-2- moφholinone, is prepared as follows: A mixture of 20.0 mmol of N-BOC-3-(S)- (4-iodophenyl)glycine, which is prepared from standard protection of (S)-(4- iodophenyl)-glycine (Registry Number 114811-48-2) 150.0 mmol of 1,2- dibromoethane, and 50.4 mmol of N,N-diisopropylethylamine in DMF is stirred at 100 °C for 20 hours. The mixture is cooled and concentrated in vacuo. The residue is partitioned between ethyl acetate and water. The layers are separated and the organic layer is washed with 0.5N KHSO 4 , two times with water, dried and concentrated in vacuo. Flash chromatography on silica gel with hexanes/ether as the eluant affords the precursor ligand compound (35), which has the basic structure of Formula (A), wherein Y is O, Z is O, A is I, and with an amino blocking group on R 1 . Second, a starting material (36) 3,5-Bis (trifluoromethyl) benzyl trifluoromethanesulfonate is prepared as follows: a solution of 4.1 mmol of 3,5- bis(trifluoromethyl)benzyl alcohol and 5.12 mmol of 2,6-di-t-butyl-4- methylpyridine in CC1 4 is treated with 4.38 mmol of trifluoromethanesulfonic anhydride and stirs at room temperature for 1.5 hours. A white precipitate forms shortly after the addition of the anhydride. The slurry is filtered under nitrogen with a Schlenk filter and the filtrate is concentrated in vacuo. The crude product is redissolved in dry toluene and used directly in the next step described below. ■ Third, the precursor and starting materials (35) and (36) are reacted together as described below to make ligand precursor compound (37) N-BOC-2- (S)-(3,5-Bis (trifluoromethyl) benzylmethoxy)-3-(S)-(4-iodophenyl)-moφholine (37). A solution of 1.9 mmol of N-BOC-3-(S)-(4-iodophenyl)-2-moφholinone (35) in dry THF at -75 °C is treated with 2.1 mmol of 1.0M solution of L- Selectride® in THF. The resulting mixture is stirred cold for 30 minutes, then is treated with 4.1 mmol of freshly prepared 3,5-Bis(trifluoromethyl)benzylmethyl trifluoromethanesulfonate (36) in toluene solution, maintaining the internal temperature below -60 °C. The reaction mixture is stirred at -75 °C for 1 hour and at —40 °C for 2 hours. The cold solution is partitioned between ethyl acetate and saturated NaHCO 3 and the layers are separated. The aqueous layer is extracted with ethyl acetate; the organic extracts are combined, dried and concentrated in vacuo. Flash chromatography on silica gel using hexanes/ethyl acetate as the eluant affords the ligand precursor compound (37), also having a basic structure of Formula (A), wherein Y is O, Z is OB and B is a substituted arylmethyl, having two trifluoromethyl substitutions thereon, R 1 is an amino blocking group BOC and A is I. Fourth, the ligand precursor compound (37) is converted into ligand precursor compound (38) 2-(S)-(3,5-Bis(trifluoromethyl)benzylmethoxy)-3-(S)- (4-iodophenyl)-τnθφholine as follows: (1 mmol) of precursor compound (37) is dissolved in CH 2 C1 2 . A solution of 10% trifluoroacetic acid in CH 2 C1 2 is added and the reaction is stirred for 1 hour at room temperature. The solvent is then removed in vacuo to provide the desired material as the TFA salt. The precursor compound (38) is then purified from this mixture using reverse phase HPLC. The blocking group BOC was removed from the N4 position such that R 1 is now hydrogen and available for reaction in the next step. Fifth, the monovalent ligand (40a) 2-(S)-(3,5-Bis (trifluoromethyl) benzylmethoxy)-3-(S)-(4-iodophenyl)-4-(5-(3-oxo-l,2,4-triazolo) methyl moφholine illustrated in Figure 6B is formed from the precursor compound (38) in accordance with the following steps: N-Methoxycarbonyl-2- bromoacetamidrazone (39) (Yanagisawa, I.; Hirata, Y.; Ishii, Y. J. Med. Chem. 1984, 27, 849-857) is used as the alkylating agent and methylcyanide is used as the solvent. Flash chromatography on silica gel using CH 2 Cl 2 /methanol/NH 4 OH as the eluant affords 2-(S)-(3,5-Bis(trifluoromethyl)benzylmethoxy)-3-(S)-(4- iodophenyl)-4-(2-N-methoxy-carbonylacetamidrazono)moφholine. A mixture of 1.1 mmol of 2-(S)-(3,5-Bis(trifluoromethyl)benzylmethoxy)-3-(S)-(4- iodophenyl)-4-(2-N-methoxy-carbonylacetamidrazono)moφholine in xylenes is heated at reflux. Dissolution of the solid occurs on warming. After 3 hours, the solution is cooled and concentrated in vacuo. Flash chromatography on silica gel using CH 2 Cl 2 /methanol /NH 4 OH as the eluant affords the crude product. Recrystallization from hexanes/ethyl acetate affords the monovalent ligand (40a). The monovalent ligand (40a) has the preferred Formula (B), where Z is O, B is a trifluoromethyl disubstituted phenyl, A is a. para- iodo-substituted phenyl, Y is O, R 1 is 2,4-dihydro-3-oxo-l,2,4-triazol-5-ylmethyl group, and R 2 and R 3 are hydrogen. C2-C2-Linked Compounds (Type lb) Example 5 Bivalent compound (61a) is made from monovalent ligands (60a) having the basic structure of Formula (A) wherein A is a H; Y is O; Z is OH; R is H; having a precursor R 1 amino blocking group. R 1 is converted to 2,3-dihydro-3- oxo-l,2,4-triazol-5-ylmethyl upon completion of the synthesis of the bivalent ligand (61a). The monovalent ligands (60a) are linked together with a linker dibromo xylene (9a) in the first step. The linkage is at the moφholino (Y=O) C2 position via the hydroxy (Z) group and the xylene linker moiety (R 6 ) becomes a part of the multi-binding compound (61a) in accordance with the invention. Compound (61a) may be prepared as shown in Figure 9 and as described below. Figure 9 illustrates the preparation of multi-binding compound (61a). A precursor ligand compound (60a) N-BOC-2-(S)-hydroxy-3-(S)- phenylmoφholine, having the basic structure of Formula (A) is prepared according to the procedure described above in Example 4 and illustrated in Figure 7 for starting material (35). In this embodiment, the ligand precursors are linked together with a linker (9a) as the first step in forming the multi-binding compound (61a) of the invention. The precursor compound (60a) is linked with linker (9a) in accordance with the following steps: A solution of 20 mmols of precursor compound 60a in DMF with 10 mmols of α, '-dibromo-p-xylene (9a) and 20 mmols of potassium carbonate is heated as necessary and the reaction followed by TLC. When the reaction is judged complete, the mixture is partitioned between isopropyl acetate and water and the organic phase washed with water, dried over sodium sulfate and the solvent removed in vacuo. The residue is purified by chromatography to afford the linked intermediate precursor material (58). The linked intermediate precursor material (58) (1 mmol) is dissolved in CH 2 C1,. A solution of 10% trifluoroacetic acid in CH 2 C1 2 is added and the reaction is stirred for 1 hour at room temperature to replace the amino blocking groups with hydrogen on R 1 . The solvent is then removed in vacuo to provide the linked precursor material (59) as the TFA salt. The linked precursor material (59) is then purified from this mixture using reverse phase HPLC. The desired multi-binding ligand compound of the invention (61a) is formed from a reaction of precursor material (59) and N-methoxycarbonyl-2-bromoacetamidrazone (39) in much the same way that monovalent ligand (40a) is formed from precursor material (38) described above in Example 4 and illustrated in Figure 7. Example 6 Bivalent compound (81a) is made from monovalent precursor ligands (78) having the basic structure of Formula (A) wherem A is a H; Y is CH 2 ; Z is =NOH; R is oxo; R 1 is first H and then 2,3-dihydro-3-oxo-l,2,4-triazol-5- ylmethyl. The monovalent ligands (78) are first linked together with linker (10a) dialdehyde xylene. The monovalent ligands (78) are linked at the piperidyl (Y=CH 2 ) C2 position via the isonitroso groups (Z) with the xylene (R°) linker (10a) moiety becoming a part of the multi-binding compound (81a) in accordance with the invention. Compound (81a) may be prepared as shown in Figure 1 1 and as described below. Figure 11 illustrates a ligand precursor material (78) (2-oxo-5-oximino-6- phenylpyridine), having the basic structure of Formula (A), is first prepared from trans-5-nitro-2-oxo-6-phenylpiperdine as described in Patent EP-0436334(B1), incoφorated herein by reference. The ligand precursor material (78) is linked together in the next step. Precursor material (78) (2-Oxo-5-oximino-6- phenylpiperdine) (330 mmol) is dissolved (heating on steam bath is necessary to achieve a clear solution) in ethanol containing methanol. Neutral Raney Ni is added and the mixture is filtered through diatomaceous earth (Celite®) which is thoroughly washed with methanol. The organic solvents are removed using a rotary evaporator to afford an oil that solidifies on standing. The resulting cis/trans mixture is dissolved in methanol and the pH is adjusted to 5 using saturated methanolic hydrochloric acid. Four Angstrom sieves, sodium cyanoborohydride (138 mmol) and the linker benzene- 1 ,4-bisaldehyde (10a), (165 mmol) are added to the system. Stirring is continued until the reaction is complete as indicated by TLC. The reaction mixture is filtered through diatomaceous earth (Celite®) and the filtrate is concentrated using a rotary evaporator. The residue is suspended in water and the pH made basic. The aqueous phase is extracted with methylene chloride, washed with water, brine, and then dried (with anhydride magnesium sulfate) and concentrated to give an oil. Flash chromatography followed by elution with 3% methanol in methylene chloride affords a linked intermediate material (79). The linked intermediate material (79) is converted into the multi-binding ligand (81a) in accordance with the invention using a procedure described in Patent EP-0436334(B1), incoφorated herein by reference, as well as the N-alkylation procedure steps (converting precursor material (38) into monovalent ligand (40a)) described above in relation to Example 4 and Figure 7. It should be noted that isolation and purification of the compounds and intermediates described herein can be effected, if desired, by any suitable separation or purification method such as, for example, filtration, extraction, crystallization, column chromatography, thin layer chromatography, thick layer chromatography, preparative low or high-pressure liquid chromatography or a combination of these procedures. It is not the intent that this invention to be limited to one isolation or purification method. REPRESENTATTVF. ASSAYS The following assays are used to evaluate the multi-binding compounds of this invention. In vitro binding assay Using the neurokinin receptor binding assay described by Cascieri, M. A, et al. 17 the pKi for NK1 receptor binding is determined for the multi-binding compounds of this invention. Ex vivo model for depression Using the distress vocalization in rat (or preferably, Guinea pig) pups assay described in Kramer, M. S. et al. 10 and Reference 16, stress responses using the multi-binding compounds of this invention are measured. In yjyo model for CNS penetration Using the gerbil foot tapping an chromodacryorrhoea in gerbils described by Rupniak, Nadia, M. J. et al., 12 the multi-binding compounds of this invention are tested. Cisplatin-induced emesis in Ferrets for Emesis Using the cisplatin-induced emesis ferret model described in Rupniak, Nadia, M.J. et al., 13 multi-binding compounds of this invention are tested for their ability to reduce the emetic effects of cisplatin in ferrets. While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto.

Claims: WHAT IS CLAIMED IS: 1. A multi-binding compound and salts thereof comprising 2 to 10 ligands, which may be the same or different and which are covalently attached to a linker or linkers which may be the same of different, at least one of said ligands comprising a ligand domain capable of binding to a neurokinin receptor. 2. The multi-binding compound according to Claim 1 wherein at least two and more preferably each of the ligands comprises a ligand domain capable of binding to a neurokinin receptor. 3. A multi-binding compound represented by formula I: (L) p (X) q I wherein: each L is a ligand that may be the same or different at each occurrence; each X is a linker that may be the same or different at each occurrence; p is an integer of from 2 to 10; q is an integer of from 1 to 20; wherein at least one ligand comprises a ligand domain capable of binding to a neurokinin receptor; and wherein the multi-binding compound includes pharmaceutically acceptable salts thereof. 4. The multi-binding compound of claim 3, wherein q is less than p. 5. The multibinding compound of claim 1, wherein one or more of the ligands comprises a group represented by formula (A): wherein: Z is CH 2 B, NHB, NOB, =NB, =0, OB, or SB, wherein: B is H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y is CHB, NB, NR, O, or S; R 1 is B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen-containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A is hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; with the proviso that the compound includes one B moiety which is a direct link to the linker. 6. The multibinding compound ofclaim 1, wherein one or more of the ligands comprises a group represented by formula (B): R 2 R 1 (B) wherein: Z represents CH 2 , NB, NOH, NR, O, or S; B represents aryl, substituted aryl or a direct covalent link to the linker; A represents aryl, substituted aryl or a direct link to the linker; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; R 1'3 are, independently, B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen- containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; and Y is CHB, NB, NR, 0, or S; 7. The multibinding compound ofclaim 1 wherein the linker comprises a group represented by formula III: E'-R 6 -E 2 III wherein: R 6 is a linker moiety selected from the group consisting of alkyl, substituted alkyl, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenyl, substituted alkenyl, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, aryl, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; and E 1 and E 2 are reactive groups capable of reacting with either an amino, hydroxy, halo, alkyl, or thiol containing group on the ligands or a ligand precursor thereof to form a linkage. 8. The multi-binding compound of claim 7, wherein E 1 and £ 2 are selected from the group consisting of halogen, haloalkyl; carboxyl, carboxyalkyl, acyl, acyloxy, and halo-containing acyl. 9. A multibinding compound of formula II: L'— X'— L' II wherein each L' is independently a ligand comprising a ligand domain capable of binding to a neurokinin receptor and X' is a linker; and pharmaceutically- acceptable salts thereof. 10. The multibinding compound of claim 9, wherein one or more of the ligands comprises a group represented by formula (A): wherein: Z is CH 2 B, NHB, NOB, =NB, O, OB, or SB, wherein: B is H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y is CHB, NB, NR, 0, or S; R 1 is B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen-containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A is hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, " substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; with the proviso that the compound includes one B moiety which is a direct link to the linker. 11. The multibinding compound of claim 9, wherein one or more of the ligands comprises a group represented by formula (B): wherein: Z represents CH 2 , NB, NOH, NR, O, or S; B represents aryl, substituted aryl or a direct covalent link to the linker; A represents aryl, substituted aryl or a direct link to the linker; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; R 1"3 are, independently, B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen- containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; and Y is CHB, NB, NR, O, or S; 12. The multibinding compound of claim 9 wherein the linker comprises a group represented by formula III: E'-R 6 -E 2 III wherein: R 6 is a linker moiety selected from the group consisting of alkyl, substituted alkyl, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenyl, substituted alkenyl, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, aryl, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; and E x and E 1 are reactive groups capable of reacting with either an amino, hydroxy, halo, alkyl, or thiol containing group on the ligands or a ligand precursor thereof to form a linkage. 13. The multi-binding compound ofclaim 9, wherein E l and E 2 are selected from the group consisting of halogen, haloalkyl; carboxyl, carboxyalkyl, acyl, acyloxy, and halo-containing acyl. 14. The multi-binding compound of Claim 10, wherein the substitution on the aryl group of A is a group selected from a halogen or haloalkyl. 15. The multi-binding compound of Claim 10, wherein B is substituted aryl comprising one or more substitutions which are either the same or different ones of the groups selected from CF 3 , OCH 3 , OCF 3 , or a substituted nitrogen- containing heterocyclyl group. 16. The multi-binding compound of Claim 15 wherein the substituted nitrogen-containing heterocyclyl group comprises a substituted tetrazole. 17. The multi-binding compound of Claim 15, wherein the substitution on the aryl of B is selected from: 3,5- trifluoromethylphenyl, 2-methoxy-(5-(2-trifluoromethyl)tetrazole)phenyl, or 2-methoxy-(5-trifluoromethoxy)phenyl. 18. The multi-binding compound of Claim 10, wherein R 1 is a nitrogen- containing heterocyclylalkyl group comprising a substituted-triazolyl methyl. 19. The multi-binding compound of Claim 3, wherein one or more of the ligands L is a group selected from the group consisting of : 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylethoxy)-3-(S)-(4-fluoro)phenyl- 4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (MK-869); 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylmethoxy)-3-(S)-(4- fluoro)phenyl-4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (LY-754-030); N-[[2-methoxy-5-(trifluoromethoxy) phenyl]methyl]-2-phenyl-,(2S-cis)- 3- piperidinamine (CP-122721); 2(S)-Phenyl-3(S)-(3,5-bis(trifluoromethyl) benzyl-oxy) piperidine (LY-733- 060); 2(S)-((3,5-Bis(trifluoromethyl)benzyl)-oxy)-3(S)-phenyl-4-((3-oxo-l,2,4- triazol-5-yl)methyl)moφholine (L-742-694); N-[[2-methoxy-5-[5-(trifluoromethyl)-lH-tetrazol-l-yl]phenyl]methyl]-2- phenyl-3-piperidinamine (GW-205171); and 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl)phenylmethoxy)-3-(S)-(4- fluoro)phenylmoφholine (LY-742-311). 20. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a multibinding compound comprising from 2 to 10 ligands which can be the same or different and which are covalently attached to one or more linkers, wherein at least one of said ligands comprises a ligand domain capable of binding to a neurokinin receptor; and pharmaceutically- acceptable salts thereof. 21. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount of a multibinding compound of formula I or II. 22. The pharmaceutical composition of Claim 21 , wherein the compound is of formula I and q is less than/?. 23. The pharmaceutical composition of Claim 20 wherein one or more of the ligands comprises a group represented by formula (A): wherein: Z is CH 2 B, NHB, NOB, =N_B, =O, OB, or SB, wherein: B is H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y is CHB, NB, NR, 0, or S; R 1 is B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen-containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A is hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; with the proviso that the compound includes one B moiety which is a direct link to the linker. 24. The pharmaceutical composition of Claim 20, wherein one or more of the ligands comprises a group represented by formula (B): R 2 wherein: Z represents CH 2 , NB, NOH, NR, O, or S; B represents aryl, substituted aryl or a direct covalent link to the linker; A represents aryl, substituted aryl or a direct link to the linker; and R is selected from the group consisting of __?, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; R 1"3 are, independently, B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen- containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; and Y is CHB, NB, NR, O, or S; 25. The pharmaceutical composition of Claim 20 wherein the linker comprises a group represented by formula III: E'-R 6 -E 2 III wherein: R 6 is a linker moiety selected from the group consisting of alkyl, substituted alkyl, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenyl, substituted alkenyl, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, aryl, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; and E l and E 2 are reactive groups capable of reacting with either an amino, hydroxy, halo, alkyl, or thiol containing group on the ligands or a ligand precursor thereof to form a linkage. 26. The pharmaceutical composition of Claim 20, wherein E 1 and E 2 are selected from the group consisting of halogen, haloalkyl; carboxyl, carboxyalkyl, acyl, acyloxy, and halo-containing acyl. 27. The pharmaceutical composition of Claim 26, wherein the substitution on the aryl group of A is a group selected from a halogen or haloalkyl. 28. The pharmaceutical composition of Claim 26, wherein B is substituted aryl comprising one or more substitutions which are either the same or different ones of the groups selected from CF 3 , OCH 3 , OCF 3 , or a substituted nitrogen- containing heterocyclyl group. 29. The pharmaceutical composition of Claim 28 wherein the substituted nitrogen-containing heterocyclyl group comprises a substituted tetrazole. 30. The pharmaceutical composition of Claim 28, wherein the substitution on the aryl of B is selected from: 3,5- trifluoromethylphenyl, 2-methoxy-(5-(2-trifluoromethyl)tetrazole)phenyl, or 2-methoxy-(5-trifluoromethoxy)phenyl. 31. The pharmaceutical composition of Claim 23, wherein R' is a nitrogen-containing heterocyclylalkyl group comprising a substituted-triazolyl methyl. 32. The pharmaceutical composition of Claim 20, wherein one or more of the ligands L is a group selected from the group consisting of : 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylethoxy)-3-(S)-(4-fluoro)phenyl- 4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (MK-869); 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylmethoxy)-3-(S)-(4- fluoro)phenyl-4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (LY-754-030); N-[[2-methoxy-5-(trifluoromethoxy) phenyl]methyl]-2-phenyl-,(2S-cis)- 3- piperidinamine (CP-122721); 2(S)-Phenyl-3(S)-(3,5-bis(trifluoromethyl) benzyl-oxy) piperidine (LY-733- 060); 2(S)-((3,5-Bis(trifluoromethyl)benzyl)-oxy)-3(S)-ρhenyl-4-((3-oxo-l,2,4- triazol-5-yl)methyl)moφholine (L-742-694); N-[[2-methoxy-5-[5-(trifluoromethyl)-lH-tetrazol-l-yl]phenyl]methyl]-2- phenyl-3-piperidinamine (GW-205171); and 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl)phenylmethoxy)-3-(S)-(4- fluoro)phenylmoφholine (LY-742-311). 33. The pharmaceutical composition according to Claim 20 wherein at least one of said ligands modulates one or more conditions selected from the group consisting of nociception, central stress response, neurogenic inflammation, smooth muscle contraction, vasodilation and secretion and immune system activation. 34. A method for inhibiting disorders or conditions selected from the group consisting of Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthritis, cystitis, osteoarthritis, irritable bowel syndrome, allergic rhinitis, pain, chronic pain, migraine headaches, asthma, bronchitis, and chemotherapy induced emesis in a mammal mediated by neurokinin receptors, which method comprises administering to said mammal an effective amount of a pharmaceutical composition comprising a pharmaceutically acceptable excipient and an effective amount of a multi-binding compound, or a pharmaceutically acceptable salt thereof, comprising 2 to 10 ligands which may be the same or different and which are covalently attached to a linker or linkers which may be the same or different, at least one of said ligands comprising a ligand domain capable of binding to one or more of the neurokinin receptors. 35. The method ofclaim 34, wherein the compound is of Formula I or II. 36. The method of claim 35, wherein q is less than p. 37. The method ofclaim 34, wherein one or more of the ligands comprises a group represented by formula (A): wherein: Z is CH 2 B, NHB, NOB, =NB, O, OB, or SB, wherein: B is H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y is CHB, NB, NR, O, or S; R 1 is B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen-containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A is hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; with the proviso that the compound includes one B moiety which is a direct link to the linker. 38. The method ofclaim 34, wherein one or more of the ligands comprises a group represented by formula (B): wherein: Z represents CH 2 , NB, NOH, NR, O, or S; B represents aryl, substituted aryl or a direct covalent link to the linker; A represents aryl, substituted aryl or a direct link to the linker; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene. substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; R 1"3 are, independently, B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen- containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; and Y is CHB, NB, NR, O, or S; 39. The method ofclaim 34, wherein the linker comprises a group represented by formula III: E'-R 6 -E 2 III wherein: R 6 is a linker moiety selected from the group consisting of alkyl, substituted alkyl, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenyl, substituted alkenyl, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, aryl, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; and E l and E 2 are reactive groups capable of reacting with either an amino, hydroxy, halo, alkyl, or thiol containing group on the ligands or a ligand precursor thereof to form a linkage. 40. The method ofclaim 39, wherein E 1 and E 2 are selected from the group consisting of halogen, haloalkyl; carboxyl, carboxyalkyl, acyl, acyloxy, and halo-containing acyl. 41. The method of Claim 37, wherein the substitution on the aryl group of A is a group selected from a halogen or haloalkyl. 42. The method of Claim 38, wherein B is substituted aryl comprising one or more substitutions which are either the same or different ones of the groups selected from CF 3 , OCH 3 , OCF , or a substituted nitrogen-containing heterocyclyl group. 43. The method of Claim 42 wherein the substituted nitrogen-containing heterocyclyl group comprises a substituted tetrazole. 44. The method of Claim 42, wherein the substitution on the aryl of B is selected from: 3,5- trifluoromethylphenyl, 2-methoxy-(5-(2-trifluoromethyl)tetrazole)phenyl, or 2-methoxy-(5-trifluoromethoxy)phenyl. 45. The method of Claim 37, wherein R' is a nitrogen-containing heterocyclylalkyl group comprising a substituted-triazolyl methyl. 46. The method of Claim 34, wherein one or more of the ligands L is a group selected from the group consisting of : 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylethoxy)-3-(S)-(4-fluoro)phenyl- 4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (MK-869); 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl) phenylmethoxy)-3-(S)-(4- fluoro)phenyl-4-(3-oxo-l,2,4-triazol-5-yl-)methylmoφholine (LY-754-030); N-[[2-methoxy-5-(trifluoromethoxy) phenyl]methyl]-2-phenyl-,(2S-cis)- 3- piperidinamine (CP-122721); 2(S)-Phenyl-3(S)-(3,5-bis(trifluoromethyl) benzyl-oxy) piperidine (LY-733- 060); 2(S)-((3,5-Bis(trifluoromethyl)benzyl)-oxy)-3(S)-phenyl-4-((3-oxυ-l,2,4- triazol-5-yl)methyl)moφholine (L-742-694); N-[[2-methoxy-5-[5-(trifluoromethyl)-lH-tetrazol-l-yl]phenyl]methyl]-2- phenyl-3-piperidinamine (GW-205171); and 2-(R)-(l-(R)-3,5-Bis(trifluoromethyl)phenylmethoxy)-3-(S)-(4- fluoro)phenylmoφholine (LY-742-311). 47. A multi-binding compound represented by formula I: ( ) p (X) q wherein: each L is a ligand that may be the same or different at each occunence; each X is a linker that may be the same or different at each occurrence; p is an integer of from 2 to 10; q is an integer of from 0 to 20; wherein at least one ligand comprises a ligand domain capable of binding to a neurokinin receptor; and wherein the multi-binding compound includes pharmaceutically acceptable salts thereof. 48. The multibinding compound of claim 47, wherein one or more of the ligands comprises a group represented by formula (A): wherein: Z is CH 2 .B, NHB, NOB, =NB, =0, OB, or SB, wherein: __? is H, alkyl, substituted alkyl, alkenyl, substituted alkenyl, aryl, alkaryl, or a direct covalent link to a linker; Y is CHB, NB, NR, O, or S; R 1 is B, cycloalkyl, substituted cycloalkyl, cycloalkylene, substituted cycloalkylene, cycloalkenyl, substituted cycloalkenyl, a nitrogen-containing heterocyclyl alkyl, alkylene, substituted alkylene, alkoxy or substituted alkoxy; A is hydrogen, halogen or a haloalkyl group; and R is selected from the group consisting of B, oxo, alkylene, substituted alkylene, alkaryl, alkoxy, substituted alkoxy, alkylalkoxy, alkenylene, substituted alkenylene, alkynyl, substituted alkynyl, alkynylene, acyl, acylamino, aminoacyl, acyloxy, substituted aryl, aryloxy, arylene, substituted arylene, carboxyalkyl, cycloalkyl, substituted cycloalkyl, cycloalkylene, cycloalkenyl, substituted cycloalkenyl, haloalkyl, heteroaryl, substituted heteroaryl, heteroaryloxy, heteroarylene, and oxyacylamino; 49. A pharmaceutical composition comprising a pharmaceutically acceptable excipient and an effective amount of the multi-binding compound of claim 47. 50. A method for treating one or more disorders selected from Parkinson's disease, Alzheimer's disease, depression, anxiety, inflammation, rheumatoid arthritis, cystitis, osteoarthritis, irritable bowel syndrome, allergic rhinitis, pain, chronic pain, migraine headaches, asthma, bronchitis and chemotherapy induced emesis in a mammal mediated by neurokinin receptors, which method comprises administering to said mammal an effective amount of a pharmaceutical composition comprising a pharmaceutically acceptable excipient and an effective amount of a multi-binding compound of claim 47. 51. The multi-binding compound of Claim 1 , wherein the neurokinin receptor is NK,. 52. The pharmaceutical composition of Claim 20, wherein the neurokinin receptor is NK,. 53. The method of Claim 34, wherein the neurokinin receptor is NK,. 54. A method for identifying multimeric ligand compounds possessing multibinding properties which method comprises: (a) identifying a ligand or a mixture of ligands wherein each ligand comprises a ligand domain capable of binding to a neurokinin receptor and contains at least one reactive functionality; (b) identifying a library of linkers wherein each linker in said library comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the ligand or mixture of ligands identified in (a) with the library of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands; and (d) assaying the multimeric ligand compounds produced in the library prepared in (c) above to identify multimeric ligand compounds possessing multibinding properties. 55. A method for identifying multimeric ligand compounds possessing multibinding properties which method comprises: (a) identifying a library of ligands wherein each ligand comprises a ligand domain capable of binding to a neurokinin receptor and contains at least one reactive functionality; (b) identifying a linker or mixture of linkers wherein each linker comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the library of ligands identified in (a) with the linker or mixture of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands; and (d) assaying the multimeric ligand compounds produced in the library prepared in (c) above to identify multimeric ligand compounds possessing multibinding properties. 56. The method according to Claim 54 or 55 wherein the preparation of the multimeric ligand compound library is achieved by either the sequential or concurrent combination of the two or more stoichiometric equivalents of the ligands identified in (a) with the linkers identified in (b). 57. The method according to Claim 56 wherein the multimeric ligand compounds comprising the multimeric ligand compound library are dimeric. 58. The method according to Claim 57 wherein the dimeric ligand compounds comprising the dimeric ligand compound library are heteromeric. 59. The method according to Claim 58 wherein the heteromeric ligand compound library is prepared by sequential addition of a first and second ligand. 60. The method according to Claim 56 or 57 wherein, prior to procedure (d), each member of the multimeric ligand compound library is isolated from the library. 61. The method according to Claim 58 wherein each member of the library is isolated by preparative liquid chromatography mass spectrometry (LCMS). 62. The method according to Claim 54 or 55 wherein the linker or linkers employed are selected from the group comprising flexible linkers, rigid linkers, hydrophobic linkers, hydrophilic linkers, linkers of different geometry, acidic linkers, basic linkers, linkers of different polarization and/or polarizability and amphiphilic linkers. 63. The method according to Claim 62 wherein the linkers comprise linkers of different chain length and/or having different complementary reactive groups. 64. The method according to Claim 63 wherein the linkers are selected to have different linker lengths ranging from about 2 to 100A. 65. The method according to Claim 54 or 55 wherein the ligand or mixture of ligands is selected to have reactive functionality at different sites on said ligands. 66. The method according to Claim 65 wherein said reactive functionality is selected from the group consisting of carboxylic acids, carboxylic acid halides, carboxyl esters, amines, halides, pseudohalides, isocyanates, vinyl unsaturation, ketones, aldehydes, thiols, alcohols, anhydrides, boronates, and precursors thereof wherein the reactive functionality on the ligand is selected to be complementary to at least one of the reactive groups on the linker so that a covalent linkage can be formed between the linker and the ligand. 67. The method according to Claim 54 or 55 wherein the multimeric ligand compound library comprises homomeric ligand compounds. 68. The method according to Claim 54 or 55 wherein the multimeric ligand compound library comprises heteromeric ligand compounds. 69. A library of multimeric ligand compounds which may possess multivalent properties which library is prepared by the method comprising: (a) identifying a ligand or a mixture of ligands wherein each ligand comprises a ligand domain capable of binding to a neurokinin receptor, contains at least one reactive functionality; (b) identifying a library of linkers wherein each linker in said library comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; and (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the ligand or mixture of ligands identified in (a) with the library of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands. 70. A library of multimeric ligand compounds which may possess multivalent properties which library is prepared by the method comprising: (a) identifying a library of ligands wherein each ligand comprises a ligand domain capable of binding to a neurokinin receptor and contains at least one reactive functionality; (b) identifying a linker or mixture of linkers wherein each linker comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand; and (c) preparing a multimeric ligand compound library by combining at least two stoichiometric equivalents of the library of ligands identified in (a) with the linker or mixture of linkers identified in (b) under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands. 71. The library according to Claim 69 or 70 wherein the linker or linkers employed are selected from the group comprising flexible linkers, rigid linkers, hydrophobic linkers, hydrophilic linkers, linkers of different geometry, acidic linkers, basic linkers, linkers of different polarization and/or polarizability and amphiphilic linkers. 72. The library according to Claim 71 wherein the linkers comprise linkers of different chain length and/or having different complementary reactive groups. 73. The library according to Claim 72 wherein the linkers are selected to have different linker lengths ranging from about 2 to 100 A. 74. The library according to Claim 69 or 70 wherein the ligand or mixture of ligands is selected to have reactive functionality at different sites on said ligands. 75. The library according to Claim 74 wherein said reactive functionality is selected from the group consisting of carboxylic acids, carboxylic acid halides, carboxyl esters, amines, halides, pseudohalides, isocyanates, vinyl unsaturation, ketones, aldehydes, thiols, alcohols, anhydrides, boronates, and precursors thereof wherein thie reactive functionality on the ligand is selected to be complementary to at least one of the reactive groups on the linker so that a covalent linkage can be formed between the linker and the ligand. 76. The library according to Claim 69 or 70 wherein the multimeric ligand compound library comprises homomeric ligand compounds. 77. The library according to Claim 69 or 70 wherein the multimeric ligand compound library comprises heteromeric ligand compounds. 78. An iterative method for identifying multimeric ligand compounds possessing multibinding properties which method comprises: (a) preparing a first collection or iteration of multimeric compounds which is prepared by contacting at least two stoichiometric equivalents of the ligand or mixture of ligands which target a neurokinin receptor with a linker or mixture of linkers wherein said ligand or mixture of ligands comprises at least one reactive functionality and said linker or mixture of linkers comprises at least two functional groups having complementary reactivity to at least one of the reactive functional groups of the ligand wherein said contacting is conducted under conditions wherein the complementary functional groups react to form a covalent linkage between said linker and at least two of said ligands; (b) assaying said first collection or iteration of multimeric compounds to assess which if any of said multimeric compounds possess multibinding properties; (c) repeating the process of (a) and (b) above until at least one multimeric compound is found to possess multibinding properties; (d) evaluating what molecular constraints imparted or are consistent with imparting multibinding properties to the multimeric compound or compounds found in the first iteration recited in (a)- (c) above; (e) creating a second collection or iteration of multimeric compounds which elaborates upon the particular molecular constraints imparting multibinding properties to the multimeric compound or compounds found in said first iteration; (f) evaluating what molecular constraints imparted or are consistent with imparting enhanced multibinding properties to the multimeric compound or compounds found in the second collection or iteration recited in (e) above; (g) optionally repeating steps (e) and (f) to further elaborate upon said molecular constraints. 79. The method according to Claim 78 wherein steps (e) and (f) are repeated from 2-50 times. 80. The method according to Claim 78 wherein steps (e) and (f) are repeated from 5-50 times.

Inventors: GRIFFIN JOHN H, HIGGINS DEBORAH L, MARQUESS DANIEL, GRIFFIN, JOHN, H., HIGGINS, DEBORAH, L., MARQUESS, DANIEL
Applicants: ADVANCED MEDICINE INC, GRIFFIN JOHN H, HIGGINS DEBORAH L, MARQUESS DANIEL, ADVANCED MEDICINE, INC., GRIFFIN, JOHN, H., HIGGINS, DEBORAH, L., MARQUESS, DANIEL
Application year: 1999
Main classification: A61K31
IPC codes: A61K31, A61K38, A61K45, A61K47, A61P9, A61P11, A61P13, A61P15, A61P17, A61P21, A61P25, A61P27, A61P43, C07B61, C07C215, C07C217, C07C237, C07C271, C07C311, C07C323, C07D207, C07D209, C07D211, C07D213, C07D215, C07D221, C07D223, C07D235, C07D239, C07D241, C07D249, C07D257, C07D263, C07D265, C07D277, C07D295, C07D401, C07D403, C07D413, C07D417, C07D471, C07D487, C07D495, C07D519, C07K1, C07K2, C07K4, C07K7, C07K16, C40B20, G01N33, G01N37