Patent Publication Number: US-2006004073-A1

Title: Compounds, compositions, and methods

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
      This application claims the benefit of U.S. Provisional Patent Application No. 60/396,690, filed Jul. 17, 2002; which is incorporated herein by reference for all purposes. 
    
    
     FIELD OF THE INVENTION  
      This invention relates to compounds which are inhibitors of the mitotic kinesin KSP and are useful in the treatment of cellular proliferative diseases, for example cancer, hyperplasias, restenosis, cardiac hypertrophy, immune disorders, fungal disorders, and inflammation.  
     BACKGROUND OF THE INVENTION  
      Among the therapeutic agents used to treat cancer are the taxanes and vinca alkaloids, which act on microtubules. Microtubules are the primary structural element of the mitotic spindle. The mitotic spindle is responsible for distribution of replicate copies of the genome to each of the two daughter cells that result from cell division. It is presumed that disruption of the mitotic spindle by these drugs results in inhibition of cancer cell division, and induction of cancer cell death. However, microtubules form other types of cellular structures, including tracks for intracellular transport in nerve processes. Because these agents do not specifically target mitotic spindles, they have side effects that limit their usefulness.  
      Improvements in the specificity of agents used to treat cancer is of considerable interest because of the therapeutic benefits which would be realized if the side effects associated with the administration of these agents could be reduced. Traditionally, dramatic improvements in the treatment of cancer are associated with identification of therapeutic agents acting through novel mechanisms. Examples of this include not only the taxanes, but also the camptothecin class of topoisomerase I inhibitors. From both of these perspectives, mitotic kinesins are attractive targets for new anti-cancer agents.  
      Mitotic kinesins are enzymes essential-for assembly and function of the mitotic spindle, but are not generally part of other microtubule structures, such as in nerve processes. Mitotic kinesins play essential roles during all phases of mitosis. These enzymes are “molecular motors” that transform energy released by hydrolysis of ATP into mechanical force which drives the directional movement of cellular cargoes along microtubules. The catalytic domain sufficient for this task is a compact structure of approximately 340 amino acids. During mitosis, kinesins organize microtubules into the bipolar structure that is the mitotic spindle. Kinesins mediate movement of chromosomes along spindle microtubules, as well as structural changes in the mitotic spindle associated with specific phases of mitosis. Experimental perturbation of mitotic kinesin function causes malformation or dysfunction of the mitotic spindle, frequently resulting in cell cycle arrest and cell death.  
      Among the mitotic kinesins which have been identified is KSP. KSP belongs to an evolutionarily conserved kinesin subfamily of plus end-directed microtubule motors that assemble into bipolar homotetramers consisting of antiparallel homodimers. During mitosis KSP associates with microtubules of the mitotic spindle. Microinjection of antibodies directed against KSP into human cells prevents spindle pole separation during prometaphase, giving rise to monopolar spindles and causing mitotic arrest and induction of programmed cell death. KSP and related kinesins in other, non-human, organisms, bundle antiparallel microtubules and slide them relative to one another, thus forcing the two spindle poles apart. KSP may also mediate in anaphase B spindle elongation and focussing of microtubules at the spindle pole.  
      Human KSP (also termed HsEg5) has been described (Blangy, et al., Cell, 83:1159-69 (1995); Whitehead, et al., Arthritis Rheum., 39:1635-42 (1996); Galgio et al., J. Cell Biol., 135:339-414 (1996); Blangy, et al., J Biol. Chem., 272:19418-24 (1997); Blangy, et al., Cell Motil Cytoskeleton, 40:174-82 (1998); Whitehead and Rattner, J. Cell Sci., 111:2551-61 (1998); Kaiser, et al., JBC 274:18925-31 (1999); GenBank accession numbers: X85137, NM004523 and U37426), and a fragment of the KSP gene (TRIP5) has been described (Lee, et al., Mol Endocrinol., 9:243-54 (1995); GenBank accession number L40372). Xenopus KSP homologs (Eg5), as well as Drosophila KLP61 F/KRP1 30 have been reported.  
      Mitotic kinesins, including KSP, are attractive targets for the discovery and development of novel antimitotic chemotherapeutics. Accordingly, it is an object of the present invention to provide compounds, compositions and methods useful in the inhibition of KSP.  
     SUMMARY OF THE INVENTION  
      In accordance with the objects outlined above, the present invention provides compounds that can be used to treat cellular proliferative diseases. The compounds are KSP inhibitors, particularly human KSP inhibitors. The present invention also provides compositions comprising such compounds, and methods utilizing such compounds or compositions, which can be used to treat cellular proliferative diseases.  
      In one aspect, the invention relates to methods for treating cellular proliferative diseases, and for treating, disorders by inhibiting the activity of KSP. The methods employ compounds represented by Formula I:  
                 
 
 wherein: 
 
      X is optionally substituted alkylene, —C(O)—, or is absent;  
      Y is optionally substituted alkylene, —C(O)—, or is absent;  
      R 1  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-;  
      R 4  and R 5  are independently chosen from hydrogen, optionally substituted alkyl, optionally substituted alkoxy, halogen, hydroxyl, nitro, cyano, optionally substituted amino, alkylsulfonyl, alkylsulfonamido, alkylsulfanyl, carboxy, carboxyalkyl, carboxamido, aminocarbonyl, optionally substituted aryl, optionally substituted aralkyl, optionally substituted heteroaralkyl and optionally substituted heteroaryl; or R 4  and R 5 , taken together with the carbons to which they are bound, form an optionally substituted 5- to 7-membered non-aromatic ring;  
      R 2  and R 2′  are independently chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-; or R 2  and R 2′ , taken together with the carbon to which they are bound, form an optionally substituted 3- to 7-membered ring;  
      R 3  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, —C(O)—R 7 , and —S(O) 2 —R 7a ; and R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-;  
      or R 3  taken together with R 6 , and the nitrogen to which they are bound, form an optionally substituted 5- to 12-membered nitrogen-containing heterocycle, which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring;  
      or R 3  taken together with R 2  form an optionally substituted 5- to 12-membered nitrogen-containing heterocycle, which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring;  
      R 7  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, —OR 8  and —NHR 14 ;  
      R 7a  is chosen from optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, and R 14 —NH—;  
      R 8  is chosen from optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-; and  
      R 14  is hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, or optionally substituted heteroaralkyl-(Formula I including single stereoisomers and mixtures of stereoisomers);  
      a pharmaceutically acceptable salt of a compound of Formula I;  
      a pharmaceutically acceptable solvate of a compound of Formula I; and  
      a pharmaceutically acceptable solvate of a pharmaceutically acceptable salt of a compound of Formula I.  
      In one aspect, the invention relates to methods for treating cellular proliferative diseases and other disorders that can be treated by inhibiting KSP by the administration of a therapeutically effective amount of a compound of Formula I; a pharmaceutically acceptable salt of a compound of Formula I; pharmaceutically acceptable solvate of a compound of Formula I; or a pharmaceutically acceptable solvate of a pharmaceutically acceptable salt of a compound of Formula I. Such diseases and disorders include cancer, hyperplasia, restenosis, cardiac hypertrophy, immune disorders, fungal disorders and inflammation.  
      In another aspect, the invention relates to compounds useful in inhibiting KSP kinesin. The compounds have the structures shown above in Formula I; a pharmaceutically acceptable salt of a compound of Formula I; a pharmaceutically acceptable solvate of a compound of Formula I; or a pharmaceutically acceptable solvate of a pharmaceutically acceptable salt of a compound of Formula I. The invention also relates to pharmaceutical compositions comprising: a therapeutically effective amount of a compound of Formula I; a pharmaceutically acceptable salt of a compound of Formula I; a pharmaceutically acceptable solvate of a compound of Formula I; or a pharmaceutically acceptable solvate of a pharmaceutically acceptable salt of a compound of Formula I; and one or more pharmaceutical excipients. In another aspect, the composition further comprises a chemotherapeutic agent other than a compound of the present invention.  
      In an additional aspect, the present invention provides methods of screening for compounds that will bind to a KSP kinesin, for example compounds that will displace or compete with the binding of a compound of the invention. The methods comprise combining a labeled compound of the invention, a KSP kinesin, and at least one candidate agent and determining the binding of the candidate agent to the KSP kinesin.  
      In a further aspect, the invention provides methods of screening for modulators of KSP kinesin activity. The methods comprise combining a compound of the invention, a KSP kinesin, and at least one candidate agent and determining the effect of the candidate agent on the KSP kinesin activity. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Definitions  
      As used in the present specification, the following words and phrases are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise. The following abbreviations and terms have the indicated meanings throughout:  
      Ac=acetyl  
      BNB=4-bromomethyl-3-nitrobenzoic acid  
      Boc=t-butyloxy carbonyl  
      Bu=butyl  
      c-=cyclo  
      CBZ=carbobenzoxy=benzyloxycarbonyl  
      DBU=diazabicyclo[5.4.0]undec-7-ene  
      DCM=dichloromethane=methylene chloride=CH 2 Cl 2    
      DCE=dichloroethane  
      DEAD=diethyl azodicarboxylate  
      DIC=diisopropylcarbodiimide  
      DIEA=N,N-diisopropylethylamine  
      DMAP=4-N,N-dimethylaminopyridine  
      DMF=N,N-dimethylformamide  
      DMSO=dimethyl sulfoxide  
      DVB=1,4-divinylbenzene  
      EEDQ=2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline  
      Et=ethyl  
      ETOH=ethanol  
      Fmoc=9-fluorenylmethoxycarbonyl  
      GC=gas chromatography  
      HATU=O-(7-Azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate  
      HMDS=hexamethyldisilazane  
      HOAc=acetic acid  
      HOBt=hydroxybenzotriazole  
      Me=methyl  
      mesyl=methanesulfonyl  
      MTBE=methyl t-butyl ether  
      NMO=N-methylmorpholine oxide  
      PEG=polyethylene glycol  
      Ph=phenyl  
      PhOH=phenol  
      PfP=pentafluorophenol  
      PPTS=pyridinium p-toluenesulfonate  
      Py=pyridine  
      PyBroP=bromo-tris-pyrrolidino-phosphonium hexafluorophosphate  
      rt=room temperature  
      sat&#39;d=saturated  
      s-=secondary  
      t-=tertiary  
      TBDMS=t-butyldimethylsilyl  
      TES=triethylsilyl  
      TFA=trifluoroacetic acid  
      THF=tetrahydrofuran  
      TMOF=trimethyl orthoformate  
      TMS=trimethylsilyl  
      tosyl=p-toluenesulfonyl  
      Trt=triphenylmethyl  
      Alkyl is intended to include linear, branched, or cyclic aliphatic hydrocarbon structures and combinations thereof, which structures may be saturated or unsaturated. Lower-alkyl refers to alkyl groups of from 1 to 5 carbon atoms, preferably from 1 to 4 carbon atoms. Examples of lower-alkyl groups include methyl-, ethyl-, propyl-, isopropyl-, butyl-, s- and t-butyl and the like. Preferred alkyl groups are those of C 20  or below. More preferred alkyl groups are those of C 13  or below. Cycloalkyl is a subset of alkyl and includes cyclic aliphatic hydrocarbon groups of from 3 to 13 carbon atoms. Examples of cycloalkyl groups include c-propyl-, c-butyl-, c-pentyl-, norbornyl-, adamantyl and the like. Cycloalkyl-alkyl—is another subset of alkyl and refers to cycloalkyl attached to the parent structure through a non-cyclic alkyl-. Examples of cycloalkyl-alkyl-include cyclohexylmethyl-, cyclopropylmethyl-, cyclohexylpropyl-, and the like. In this application, alkyl includes alkanyl-, alkenyl and alkynyl residues; it is intended to include vinyl-, allyl-, isoprenyl and the like. When an alkyl residue having a specific number of carbons is named, all geometric isomers having that number of carbons are intended to be encompassed; thus, for example, “butyl” is meant to include n-butyl-, sec-butyl-, isobutyl and t-butyl-; “propyl” includes n-propyl-, isopropyl-, and c-propyl-.  
      Alkylene-, alkenylene-, and alkynylene—are other subsets of alkyl-, including the same residues as alkyl-, but having two points of attachment within a chemical structure. Examples of alkylene include ethylene (—CH 2 CH 2 —), propylene (—CH 2 CH 2 CH 2 —), dimethylpropylene (—CH 2 C(CH 3 ) 2 CH 2 —) and cyclohexylpropylene (—CH 2 CH 2 CH(C 6 H 13 )-). Likewise, examples of alkenylene include ethenylene (—CH═CH—), propenylene (—CH═CH—CH 2 —), and cyclohexylpropenylene (—CH═CHCH(C 6 H 13 )-). Examples of alkynylene include ethynylene (—C ═ C—) and propynylene (—CH ═ CH—CH 2 —).  
      Cycloalkenyl is a subset of alkyl and includes unsaturated cyclic hydrocarbon groups of from 3 to 13 carbon atoms. Examples of cycloalkenyl groups include c-hexenyl-, c-pentenyl and the like.  
      Alkoxy or alkoxyl refers to an alkyl group, preferably including from 1 to 8 carbon atoms, of a straight, branched, or cyclic configuration, or a combination thereof, attached to the parent structure through an oxygen (i.e., the group alkyl-O—). Examples include methoxy-, ethoxy-, propoxy-, isopropoxy-, cyclopropyloxy-, cyclohexyloxy-and the like. Lower-alkoxy refers to alkoxy groups containing one to four carbons.  
      Acyl refers to groups of from 1 to 8 carbon atoms of a straight, branched, or cyclic configuration or a combination thereof, attached to the parent structure through a carbonyl functionality. Such groups may be saturated or unsaturated, and aliphatic or aromatic. One or more carbons in the acyl residue may be replaced by oxygen, nitrogen (e.g., carboxamido), or sulfur as long as the point of attachment to the parent remains at the carbonyl. Examples include acetyl-, benzoyl-, propionyl-, isobutyryl-, oxalyl-, t-butoxycarbonyl-, benzyloxycarbonyl, morpholinylcarbonyl, and the like. Lower-acyl refers to acyl groups containing one to four carbons.  
      Alicyclic refers to a carbocyclic ring structure which may be saturated or unsaturated, but may not be a benzenoid or other aromatic system.  
      Amino refers to the group —NH 2 . The term “substituted amino” refers to the group —NHR or —NRR where each R is independently selected from the group: optionally substituted alkyl-, optionally substituted alkoxy, optionally substituted aminocarbonyl-, optionally substituted aryl-, optionally substituted heteroaryl-, optionally substituted heterocyclyl-, acyl-, alkoxycarbonyl-, sulfanyl-, sulfinyl and sulfonyl-, e.g., diethylamino, methylsulfonylamino, furanyl-oxy-sulfonamino.  
      Aminocarbonyl—refers to the group —NR c COR b , —NR c CO 2 R a , or —NR c CONR b R c , where  
      R a  is an optionally substituted C 1 -C 6  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, or heteroaryl-C 1 -C 4  alkyl-group;  
      R b  is H or optionally substituted C 1 C 6  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, or heteroaryl-C 1 -C 4  alkyl-group; and  
      R c  is hydrogen or C 1 -C 4  alkyl-; and  
      where each optionally substituted R b  group is independently unsubstituted or substituted with one or more substituents independently selected from C 1 -C 4  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, heteroaryl-C 1 -C 4  alkyl-, C 1 -C 4  haloalkyl-, —OC 1 -C 4  alkyl, —OC 1 -C 4  alkylphenyl, —C 1 -C 4  alkyl-OH, —OC 1 -C 4  haloalkyl, halogen, —OH, —NH 2 , —C 1 -C 4  alkyl-NH 2 , —N(C 1 -C 4  alkyl)(C 1 -C 4  alkyl), —NH(C 1 -C 4  alkyl), —N(C 1 -C 4  alkyl)(C 1 -C 4  alkylphenyl), —NH(C 1 -C 4  alkylphenyl), cyano, nitro, oxo (as a substitutent for heteroaryl), —CO 2 H, —C(O)OC 1 -C 4  alkyl, —CON(C 1 -C 4  alkyl)(C 1 -C 4  alkyl), —CONH(C 1 -C 4  alkyl), —CONH 2 , —NHC(O)(C 1 -C 4  alkyl), —NHC(O)(phenyl), —N(C 1 -C 4  alkyl)C(O)(C 1 -C 4  alkyl), —N(C 1 -C 4  alkyl)C(O)(phenyl), —C(O)C 1 -C 4  alkyl, —C(O)C 1 -C 4  phenyl, —C(O)C 1 -C 4  haloalkyl, —OC(O)C 1 -C 4  alkyl, —SO 2 (C 1 -C 4  alkyl), —SO 2 (phenyl), —SO 2 (C 1 -C 4  haloalkyl), —SO 2 NH 2 , —SO 2 NH(C 1 -C 4  alkyl), —SO 2 NH(phenyl), —NHSO 2 (C 1 -C 4  alkyl), —NHSO 2 (phenyl), and —NHSO 2 (C 1 -C 4  haloalkyl).  
      Antimitotic refers to a drug for inhibiting or preventing mitosis, for example, by causing metaphase arrest. Some antitumour drugs block proliferation and are considered antimitotics.  
      Aryl and heteroaryl mean a 5- or 6-membered aromatic or heteroaromatic ring containing 0 or 1-4 heteroatoms, respectively, selected from O, N, or S; a bicyclic 9- or 10-membered aromatic or heteroaromatic ring system containing 0 or 1-4 (or more) heteroatoms, respectively, selected from O, N, or S; or a tricyclic 12- to 14-membered aromatic or heteroaromatic ring system containing 0 or 1-4 (or more) heteroatoms, respectively, selected from O, N, or S. The aromatic 6- to 14-membered carbocyclic rings include, e.g., phenyl-, naphthyl-, indanyl-, tetralinyl-, and fluorenyl and the 5- to 10-membered aromatic heterocyclic rings include, e.g., imidazolyl-, pyridinyl-, indolyl-, thienyl-, benzopyranonyl-, thiazolyl-, furanyl-, benzimidazolyl-, quinolinyl-, isoquinolinyl-, quinoxalinyl-, pyrimidinyl-, pyrazinyl-, tetrazolyl and pyrazolyl-.  
      Aralkyl—refers to a residue in which an aryl moiety is attached to the parent structure via an alkyl residue. Examples include benzyl-, phenethyl-, phenylvinyl-, phenylallyl and the like. Heteroaralkyl—refers to a residue in which a heteroaryl moiety is attached to the parent structure via an alkyl residue. Examples include furanylmethyl-, pyridinylmethyl-, pyrimidinylethyl and the like.  
      Aralkoxy—refers to the group —O-aralkyl. Similarly, heteroaralkoxy—refers to the group —O-heteroaralkyl-; aryloxy—refers to the group —O-aryl-; acyloxy—refers to the group —O-acyl-; heteroaryloxy—refers to the group —O-heteroaryl-; and heterocyclyloxy—refers to the group —O-heterocyclyl (i.e., aralkyl-, heteroaralkyl-, aryl-, acyl-, heterocyclyl-, or heteroaryl is attached to the parent structure through an oxygen).  
      Carboxyalkyl—refers to the group -alkyl-COOH.  
      Carboxamido refers to the group —CONR b R c , where  
      R b  is H or optionally substituted C 1 -C 6  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, or heteroaryl-C 1 -C 4  alkyl-group; and  
      R c  is hydrogen or C 1 -C 4  alkyl-; and  
      where each optionally substituted R b  group is independently unsubstituted or substituted with one or more substituents independently selected from C 1 -C 4  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, heteroaryl-C 1 -C 4  alkyl-, C 1 -C 4  haloalkyl-, —OC 1 -C 4  alkyl-, —OC 1 -C 4  alkylphenyl, —C 1 -C 4  alkyl-OH, —OC 1 -C 4  haloalkyl, halogen, —OH, —NH 2 , —C 1 -C 4  alkyl-NH 2 , —N(C 1 -C 4  alkyl)(C 1 -C 4  alkyl), —NH(C 1 -C 4  alkyl), —N(C 1 -C 4  alkyl)(C 1 -C 4  alkylphenyl), —NH(C 1 -C 4  alkylphenyl), cyano, nitro, oxo (as a substitutent for heteroaryl), —CO 2 H, —C(O)OC 1 -C 4  alkyl, —CON(C 1 -C 4  alkyl)(C 1 -C 4  alkyl), —CONH(C 1 -C 4  alkyl), —CONH 2 , —NHC(O)(C 1 -C 4  alkyl), —NHC(O)(phenyl), —N(C 1 -C 4  alkyl)C(O)(C 1 -C 4  alkyl), —N(C 1 -C 4  alkyl)C(O)(phenyl), —C(O)C 1 -C 4  alkyl, —C(O)C 1 -C 4  phenyl, —C(O)C 1 -C 4  haloalkyl, —OC(O)C 1 -C 4  alkyl, —SO 2 (C 1 -C 4  alkyl), —SO 2 (phenyl), —SO 2 (C 1 -C 4  haloalkyl), —SO 2 NH 2 , —SO 2 NH(C 1 -C 4  alkyl), —SO 2 NH(phenyl), —NHSO 2 (C 1 -C 4  alkyl), —NHSO 2 (phenyl), and —NHSO 2 (C 1 -C 4  haloalkyl). Carboxamido is meant to include carbamoyl-; lower-alkyl carbamoyl-; benzylcarbamoyl-; phenylcarbamoyl-; methoxymethyl-carbamoyl-; and the like.  
      Halogen or halo refers to fluorine, chlorine, bromine or iodine. Fluorine, chlorine and bromine are preferred. Dihaloaryl-, dihaloalkyl-, trihaloaryl etc. refer to aryl and alkyl substituted with the designated plurality of halogens (here, 2, 2 and 3, respectively), but not necessarily a plurality of the same halogen; thus 4-chloro-3-fluorophenyl is within the scope of dihaloaryl-.  
      Heterocyclyl means a cycloalkyl or aryl residue in which one to four of the carbons is replaced by a heteroatom such as oxygen, nitrogen or sulfur. Examples of heterocycles that fall within the scope of the invention include azetidinyl-, imidazolinyl-, pyrrolidinyl-, pyrazolyl-, pyrrolyl-, indolyl-, quinolinyl-, isoquinolinyl-, tetrahydroisoquinolinyl-, benzofuranyl-, benzodioxanyl-, benzodioxyl (commonly referred to as methylenedioxyphenyl-, when occurring as a substituent), tetrazolyl-, morpholinyl-, thiazolyl-, pyridinyl-, pyridazinyl-, piperidinyl-, pyrimidinyl-, thienyl-, furanyl-, oxazolyl-, oxazolinyl-, isoxazolyl-, dioxanyl-, tetrahydrofuranyl and the like. “N-heterocyclyl” refers to a nitrogen-containing heterocycle. The term heterocyclyl encompasses heteroaryl-, which is a subset of heterocyclyl-. Examples of N-heterocyclyl residues include azetidinyl-, 4-morpholinyl-, 4-thiomorpholinyl-, 1-piperidinyl-, 1-pyrrolidinyl-, 3-thiazolidinyl-, piperazinyl and 4-(3,4-dihydrobenzoxazinyl). Examples of substituted heterocyclyl include 4-methyl-1-piperazinyl and 4-benzyl-1-piperidinyl-.  
      A leaving group or atom is any group or atom that will, under the reaction conditions, cleave from the starting material, thus promoting reaction at a specified site. Suitable examples of such groups unless otherwise specified are halogen atoms, mesyloxy, p-nitrobenzensulphonyloxy and tosyloxy groups.  
      Optional or optionally means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstances occurs and instances in which it does not. For example, “optionally substituted alkyl” includes “alkyl” and “substituted alkyl” as defined herein. It will be understood by those skilled in the art with respect to any group containing one or more substituents that such groups are not intended to introduce any substitution or substitution patterns that are sterically impractical and/or synthetically non-feasible and/or inherently unstable.  
      Substituted alkoxy refers to alkoxy wherein the alkyl constituent is substituted (i.e., —O-(substituted alkyl)). One suitable substituted alkoxy group is “polyalkoxy” or —O-(optionally substituted alkylene)-(optionally substituted alkoxy), and includes groups such as —OCH 2 CH 2 OCH 3 , and residues of glycol ethers such as polyethyleneglycol, and —O(CH 2 CH 2 O) x CH 3 , where x is an integer of about 2-20, preferably about 2-10, and more preferably about 2-5. Another suitable substituted alkoxy group is hydroxyalkoxy or —OCH 2 (CH 2 ) y OH, where y is an integer of about 1-10, preferably about 1-4.  
      Substituted—alkyl-, aryl-, and heteroaryl—refer respectively to alkyl-, aryl-, and heteroaryl wherein one or more (up to about 5, preferably up to about 3) hydrogen atoms are replaced by a substituent independently selected from the group: —R a , —OR b , —O(C 1 -C 2  alkyl)O— (as an aryl substituent), —SR b , guanidine, guanidine wherein one or more of the guanidine hydrogens are replaced with a lower-alkyl group, —NR b R c , halogen, cyano, nitro, —COR b , —CO 2 R b , —CONR b R c , —OCOR b , —OCO 2 R a , —OCONR b R c , —NR c COR b , —NR c CO 2 R a , —NR c CONR b R c , —CO 2 R b , —CONR b R c , —NR c COR b , —SOR a , —SO 2 R a , —SO 2 NR b R c , and —NR c SO 2 R a ,  
      where R a  is an optionally substituted C 1 -C 6  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, or heteroaryl-C 1 -C 4  alkyl-group,  
      R b  is hydrogen or optionally substituted C 1 -C 6  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, or heteroaryl-C 1 -C 4  alkyl-group;  
      R c  is hydrogen or C 1 -C 4  alkyl-;  
      where each optionally substituted R a  group and R b  group is independently unsubstituted or substituted with one or more substituents independently selected from C 1 -C 4  alkyl-, aryl-, heteroaryl-, aryl-C 1 -C 4  alkyl-, heteroaryl-C 1 -C 4  alkyl-, C 1 -C 4  haloalkyl-, —OC 1 -C 4  alkyl-, —OC 1 -C 4  alkylphenyl-, —C 1 -C 4  alkyl-OH, —OC 1 -C 4  haloalkyl-, halogen, —OH, —NH 2 , —C 1 -C 4  alkyl-NH 2 , —N(C 1 -C 4  alkyl)(C 1 -C 4  alkyl), —NH(C 1 -C 4  alkyl), —N(C 1 -C 4  alkyl)(C 1 -C 4  alkylphenyl), —NH(C 1 -C 4  alkylphenyl), cyano, nitro, oxo (as a substitutent for heteroaryl), —CO 2 H, —C(O)OC 1 -C 4  allyl-, —CON(C 1 -C 4  alkyl)(C 1 -C 4  alkyl), —CONH(C 1 -C 4  alkyl), —CONH 2 , —NHC(O)(C 1 -C 4  alkyl), —NHC(O)(phenyl), —N(C 1 -C 4  alkyl)C(O)(C 1 -C 4  alkyl), —N(C 1 -C 4  alkyl)C(O)(phenyl), —C(O)C 1 -C 4  alkyl-, —C(O)C 1 -C 4  phenyl-, —C(O)C 1 -C 4  haloalkyl-, —OC(O)C 1 -C 4  alkyl-, —SO 2 (C 1 -C 4  alkyl), —SO 2 (phenyl), —SO 2 (C 1 -C 4  haloalkyl), —SO 2 NH 2 , —SO 2 NH(C 1 -C 4  alkyl), —SO 2 NH(phenyl), —NHSO 2 (C 1 -C 4  alkyl), —NHSO 2 (phenyl), and —NHSO 2 (C 1 -C 4  haloalkyl).  
      In addition, “substituted alkyl” refers to an alkyl, alkylene, alkenylene or alkynylene moiety wherein one or more (up to about 3, particular 1) carbon atoms are replaced by a heteroatom selected from O, N, or S.  
      Sulfanyl refers to the groups: —S-(optionally substituted alkyl), —S-(optionally substituted aryl), —S-(optionally substituted heteroaryl), and —S-(optionally substituted heterocyclyl).  
      Sulfinyl refers to the groups: —S(O)—H, —S(O)-(optionally substituted alkyl), —S(O)-optionally substituted aryl), —S(O)-(optionally substituted heteroaryl), —S(O)-(optionally substituted heterocyclyl); and —S(O)-(optionally substituted amino).  
      Sulfonyl refers to the groups: —S(O 2 )-H, —S(O 2 )-(optionally substituted alkyl), —S(O 2 )-optionally substituted aryl), —S(O 2 )-(optionally substituted heteroaryl), —S(O 2 )-(optionally substituted heterocyclyl) , —S(O 2 )-(optionally substituted alkoxy), —S(O 2 )-optionally substituted aryloxy), —S(O 2 )-(optionally substituted heteroaryloxy), —S(O 2 )-(optionally substituted heterocyclyloxy); and —S(O 2 )-(optionally substituted amino).  
      Pharmaceutically acceptable salts refers to those salts that retain the biological effectiveness of the free compound and that are not biologically undesirable or unsuitable for pharmaceutical use, formed with a suitable acid or base, and includes pharmaceutically acceptable acid addition salts and base addition salts. Pharmaceutically acceptable acid addition salts include those derived from inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like, and those derived from organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and the like.  
      Pharmaceutically acceptable base addition salts include those derived from inorganic bases such as sodium, potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper, manganese, aluminum salts and the like. Particular embodiments are the ammonium, potassium, sodium, calcium, and magnesium salts. Base addition salts also include those derived from pharmaceutically acceptable organic non-toxic bases, including salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, and ethanolamine.  
      Protecting group has the meaning conventionally associated with it in organic synthesis, i.e. a group that selectively blocks one or more reactive sites in a multifunctional compound such that a chemical reaction can be carried out selectively on another unprotected reactive site and such that the group can readily be removed after the selective reaction is complete. A variety of protecting groups are disclosed, for example, in T. H. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, Third Edition, John Wiley &amp; Sons, New York (1999), which is incorporated herein by reference in its entirety. For example, a hydroxy protected form is where at least one of the hydroxyl groups present in a compound is protected with a hydroxy protecting group. Likewise, amines and other reactive groups may similarly be protected.  
      Solvate refers to the compound formed by the interaction of a solvent and a compound of Formula I or salt thereof. Suitable solvates of the compounds of the Formula I or a salt thereof are pharmaceutically acceptable solvates including hydrates.  
      Many of the compounds described herein contain one or more asymmetric centers (e.g. the carbon to which R 2  and R 2′  are attached where R 2  differs from R 2′ ) and may thus give rise to enantiomers, diastereomers, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-. The present invention is meant to include all such possible isomers, including racemic mixtures, optically pure forms and intermediate mixtures. Optically active (R)- and (S)-isomers may be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques. When the compounds described herein contain olefinic double bonds or other centers of geometric asymmetry, and unless specified otherwise, it is intended that the compounds include both E and Z geometric isomers. Likewise, all tautomeric forms and rotational isomers are also intended to be included.  
      When desired, the R- and S-isomers may be resolved by methods known to those skilled in the art, for example by formation of diastereoisomeric salts or complexes which may be separated, for example, by crystallization; via formation of diastereoisomeric derivatives which may be separated, for example, by crystallization, gas-liquid or liquid chromatography; selective reaction of one enantiomer with an enantiomer-specific reagent, for example enzymatic oxidation or reduction, followed by separation of the modified and unmodified enantiomers; or gas-liquid or liquid chromatography in a chiral environment, for example on a chiral support, such as silica with a bound chiral ligand or in the presence of a chiral solvent. It will be appreciated that where the desired enantiomer is converted into another chemical entity by one of the separation procedures described above, a further step may be required to liberate the desired enantiomeric form. Alternatively, specific enantiomer may be synthesized by asymmetric synthesis using optically active reagents, substrates, catalysts or solvents, or by converting one enantiomer to the other by asymmetric transformation.  
      Compounds of the Present Invention  
      The present invention is directed to a class of novel compounds, that can be described as pyrimidinone derivatives, that are inhibitors of one or more mitotic kinesins. By inhibiting mitotic kinesins, but not other kinesins (e.g., transport kinesins), specific inhibition of cellular proliferation is accomplished. While not intending to be bound by any theory, the present invention capitalizes on the finding that perturbation of mitotic kinesin function causes malformation or dysfunction of mitotic spindles, frequently resulting in cell cycle arrest and cell death. According to one embodiment of the invention,-the compounds described herein inhibit the mitotic kinesin, KSP, particularly human KSP. In another embodiment, the compounds inhibit the mitotic kinesin, KSP, as well as modulating one or more of the human mitotic kinesins selected from the group consisting of HSET (see, U.S. Pat. No. 6,361,993, which is incorporated herein by reference); MCAK (see, U.S. Pat. No. 6,331,424, which is incorporated herein by reference); CENP-E (see, PCT Publication No. WO 99/13061, which is incorporated herein by reference); Kif4 (see, U.S. Pat. No. 6,440,684, which is incorporated herein by reference); MKLP1 (see, U.S. Pat. No. 6,448,025, which is incorporated herein by reference); Kif15 (see, U.S. Pat. No. 6,355,466, which is incorporated herein by reference); Kid (see, U.S. Pat. No. 6,387,644, which is incorporated herein by reference); Mpp1, CMKrp, KinI-3 (see, U.S. Pat. No. 6,461,855, which is incorporated herein by reference); Kip3a (see, PCT Publication No. WO 01/96593, which is incorporated herein by reference); Kip3d (see, U.S. Pat. No. 6,492,151, which is incorporated herein by reference); and RabK6.  
      The methods of inhibiting a mitotic kinesin comprise contacting an inhibitor of the invention with a kinesin, particularly a human kinesin, more particularly, human KSP or fragments and variants thereof. The inhibition can be of the ATP hydrolysis activity of the KSP kinesin and/or the mitotic spindle formation activity, such that the mitotic spindles are disrupted. Meiotic spindles may also be disrupted.  
      The present invention provides inhibitors of mitotic kinesins, in particular KSP and especially human KSP, for the treatment of disorders associated with cell proliferation. The compounds, compositions and methods described herein can differ in their selectivity and are used to treat diseases of cellular proliferation, including, but not limited to cancer, hyperplasias, restenosis, cardiac hypertrophy, immune disorders, fungal disorders and inflammation.  
      Accordingly, the present invention relates to methods employing compounds represented by Formula I:  
                 
 
 wherein: 
 
      X is optionally substituted alkylene, —C(O)—, or is absent;  
      Y is optionally substituted alkylene, —C(O)—, or is absent;  
      R 1  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-;  
      R 4  and R 5  are independently chosen from hydrogen, optionally substituted alkyl, optionally substituted alkoxy, halogen, hydroxyl, nitro, cyano, optionally substituted amino, alkylsulfonyl, alkylsulfonamido, alkylsulfanyl, carboxy, carboxyalkyl, carboxamido, aminocarbonyl, optionally substituted aryl, optionally substituted aralkyl, optionally substituted heteroaralkyl and optionally substituted heteroaryl; or R 4  and R 5 , taken together with the carbons to which they are bound, form an optionally substituted 5- to 7-membered non-aromatic ring;  
      R 2  and R 2′  are independently chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-; or R 2  and R 2′ , taken together with the carbon to which they are bound, form an optionally substituted 3- to 7-membered ring;  
      R 3  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, —C(O)—R 7 , and —S(O) 2 —R 7a ; and R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-;  
      or R 3  taken together with R 6 , and the nitrogen to which they are bound, form an optionally substituted 5- to 12-membered nitrogen-containing heterocycle, which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring;  
      or R 3  taken together with R 2  form an optionally substituted 5- to 12-membered nitrogen-containing heterocycle, which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring;  
      R 7  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, —OR 8  and —NHR 14 ;  
      R 7a  is chosen from optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, and R 14 —NH—;  
      R 8  is chosen from optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-; and  
      R 14  is hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, or optionally substituted heteroaralkyl-, including single stereoisomers and mixtures of stereoisomers;  
      a pharmaceutically acceptable salt of a compound of Formula I;  
      a pharmaceutically acceptable solvate of a compound of Formula I;  
      or a pharmaceutically acceptable solvate of a pharmaceutically acceptable salt of a compound of Formula I. In a particular embodiment, the stereogenic center to which R 2  and R 2′  are attached is of the R configuration.  
      Nomenclature  
      The compounds of Formula I can be named and numbered in the manner (e.g., using AutoNom version 2.1 in ISIS-DRAW or ChemDraw) described below. For example, the compound:  
                 
 
 i.e., the compound according to Formula I where X is absent; Y is absent; R 1  is benzyl, R 2  is propyl (or i-propyl), R 2′  is hydrogen; R 3  is hydrogen; R 4  is methyl; R 5  is hydrogen; and R 6  is hydrogen can be named 2-(1-amino-2-methyl-propyl)-3-benzyl-6-methyl-pyran-4-one. 
 
      Likewise, the compound  
                 
 
 i.e., the compound according to Formula I where X is absent; Y is absent; R 1  is benzyl, R 2  is ethyl, R 2′  is hydrogen; R 3  and R 6  together with the nitrogen to which they are bound form a substituted imidazolyl ring; and R 4  and R 5  are hydrogen can be named 3-benzyl-2-[1-(2-methyl-imidazol-1-yl)-propyl]-pyran-4-one. 
 
      Similarly, the compound having the formula:  
                 
 
 i.e., the compound according to Formula I where X is absent; Y is absent; R 1  is benzyl, R 2  is propyl, R 2′  is hydrogen; R 3  is —C(O)—R 7 ; R 4  is methyl; R 5  is hydrogen; R 6  is 3-aminopropyl-; and R 7  is p-tolyl can be named N-(3-amino-propyl)-N-[1-(3-benzyl-6-methyl-4-oxo-4H-pyran-2-yl)-2-methyl-propyl]-4-methyl-benzamide. 
 
 Synthetic Reaction Parameters 
 
      The compounds of Formula I can be prepared by following the procedures described with reference to the Reaction Schemes below.  
      Unless specified otherwise, the terms “solvent”, “inert organic solvent” or “inert solvent” mean a solvent inert under the conditions of the reaction being described in conjunction therewith [including, for example, benzene, toluene, acetonitrile, tetrahydrofuran (“THF”), dimethylformamide (“DMF”), chloroform, methylene chloride (or dichloromethane), diethyl ether, methanol, pyridine and the like]. Unless specified to the contrary, the solvents used in the reactions of the present invention are inert organic solvents.  
      The term “q.s.” means adding a quantity sufficient to achieve a stated function, e.g., to bring a solution to the desired volume (i.e., 100%).  
      In general, esters of carboxylic acids may be prepared by conventional esterification procedures, for example alkyl esters may be prepared by treating the required carboxylic acid with the appropriate alkanol, generally under acidic conditions. Likewise, amides may be prepared using conventional amidation procedures, for example amides may be prepared by treating an activated carboxylic acid with the appropriate amine. Alternatively, a lower-alkyl ester such as a methyl ester of the acid may be treated with an amine to provide the required amide, optionally in presence of trimethylalluminium following the procedure described in Tetrahedron Lett. 48, 4171-4173, (1977). Carboxyl groups may be protected as alkyl esters, for example methyl esters, which esters may be prepared and removed using conventional procedures, one convenient method for converting carbomethoxy to carboxyl is to use aqueous lithium hydroxide.  
      The salts and solvates of the compounds mentioned herein may as required be produced by methods conventional in the art. For example, if an inventive compound is an acid, a desired base addition salt can be prepared by treatment of the free acid with an inorganic or organic base, such as an amine (primary, secondary, or tertiary); an alkali metal or alkaline earth metal hydroxide; or the like. Illustrative examples of suitable salts include organic salts derived from amino acids such as glycine and arginine; ammonia; primary, secondary, and tertiary amines; such as ethylenediamine, and cyclic amines, such as cyclohexylamine, piperidine, morpholine, and piperazine; as well as inorganic salts derived from sodium, calcium, potassium, magnesium, manganese, iron, copper, zinc, aluminum, and lithium.  
      If a compound is a base, a desired acid addition salt may be prepared by any suitable method known in the art, including treatment of the free base with an inorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like, or with an organic acid, such as acetic acid, maleic acid, succinic acid, mandelic acid, fumaric acid, malonic acid, pyruvic acid, oxalic acid, glycolic, acid, salicylic acid, pyranosidyl acid, such as glucuronic acid or galacturonic acid, alpha-hydroxy acid, such as citric acid or tartaric acid, amino acid, such as aspartic acid or glutamic acid, aromatic acid, such as benzoic acid or cinnamic acid, sulfonic acid, such as p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, or the like.  
      Isolation and purification of the compounds and intermediates described herein can be effected, if desired, by any suitable separation or purification procedure such as, for example, filtration, extraction, crystallization, column chromatography, thin-layer chromatography or thick-layer chromatography, or a combination of these procedures. Specific illustrations of suitable separation and isolation procedures can be had by reference to the examples hereinbelow. However, other equivalent separation or isolation procedures can, of course, also be used.  
     Synthesis of the Compounds of Formula I  
      The compounds of Formula I can be prepared by following the procedures described with reference to the Reaction Schemes below.  
      Brief Description Of Reaction Schemes  
      Reaction Scheme 1 illustrates a synthesis of compounds of Formula I wherein R 3  is —C(O)R 7 .  
      Reaction Scheme 2 illustrates a synthesis of compounds of Formula I wherein R 3  is —S(O) 2 R 7a .  
      Reaction Scheme 3 illustrates a synthesis of compounds of Formula I wherein R 3  is optionally substituted alkyl.  
      Reaction Scheme 4 illustrates a synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted imidazolyl.  
      Reaction Scheme 5 illustrates an alternative synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted imidazolyl.  
      Reaction Scheme 6 illustrates a synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted imidazolinyl.  
      Reaction Scheme 7 illustrates an alternative synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted imidazolinyl.  
      Reaction Scheme 8 illustrates a synthesis of compounds of Formula 101 which can be used as a starting material for the preparation of compounds of Formula 1.  
      Reaction Scheme 9 illustrates a synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted imidazolyl.  
      Reaction Scheme 10 illustrates an alternative synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted imidazolinyl.  
      Reaction Scheme 11 illustrates a synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted diazepinone.  
      Reaction Scheme 12 illustrates an alternative synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted diazepinone.  
      Reaction Scheme 13 illustrates a synthesis of compounds of Formula I wherein R 3  and R 6 , taken together with the nitrogen to which they are bound, form an optionally substituted piperazine or diazepam.  
      Starting Materials  
      The optionally substituted compounds of Formula 101 are commercially available, e.g., from Aldrich Chemical Company, Milwaukee, Wis. or may be readily prepared by those skilled in the art using commonly employed synthetic methodology.  
                 
 
 Preparation of Formula 103 
 
      Referring to Reaction Scheme 1, Step 1, an excess, and preferably about 2.2 equivalents of lithium bis(trimethylsilyl)amide in a nonpolar, aprotic solvent such as THF is added slowly via syringe to a −78° C. solution of a compound of Formula 101, wherein PG is a protecting group and more preferably, is a Boc group, in a nonpolar, aprotic solvent such as THF. The reaction solution temperature is monitored by an internal thermometer, and addition of the base is done at a rate sufficient to prevent the temperature from exceeding −48° C. After the addition is complete the resulting solution was maintained at −78° C. for about 30 mins. A solution of a compound of Formula 102 in a nonpolar, aprotic solvent such as THF is added dropwise via syringe. The reaction solution is maintained for about 30 mins. The resulting compound of Formula 103 is isolated and used without further purification.  
      Preparation of Formula 105  
      Referring to Reaction Scheme 1, Step 2, a solution of a compound of Formula 103 and about an equivalent of Dess-Martin periodinane (prepared as described in Dess, D. B.; Martin, J. C.  J. Org. Chem.  1993, 48, 4156), in a polar, aprotic solvent such as methylene chloride is maintained at room temperature for about 45 mins. The resulting compound of Formula 105 is isolated and used without further purification.  
      Preparation of Formula 107  
      A mixture of the ketone of Formula 105, an excess (and preferably about 2.2 equivalents) of a base, such as potassium carbonate, in a polar, aprotic solvent such as DMF, is maintained at about 75° C. for about 20 mins. The resulting pyranone of Formula 107 is isolated and purified.  
      Preparation of Formula 109  
      Referring to Reaction Scheme 1, Step 4, the amino protecting group of a compound of Formula 107 is removed. For example, to a solution of a compound of Formula 107 wherein the amino protecting group, PG, is Boc in a nonpolar, aprotic solvent such as dichloromethane is added trifluoroacetic acid, while maintaining the temperature at about 0° C. The resulting solution is then stirred at room temperature for one hour and concentrated in vacuo. The product, a compound of Formula 109 is isolated and used in the next step without further purification. One of skill in the art will readily appreciate that the removal of other protecting groups can be accomplished using conditions known in the art. See, e.g., Greene, et al. supra.  
      Preparation of Formula 111  
      Referring to Reaction Scheme 1, Step 5, to a solution of a compound of Formula 109 is added successively a slight excess (preferably about 1.2 equivalents) of an aldehyde comprising R 6′  (i.e., a compound having the formula R 6′ CHO where R 6′ CH 2 — is equivalent to R 6  and R 6  is as described above or is a protected precursor to such a substituent, e.g., (3-oxo-propyl)-carbamic acid tert-butyl ester) and a reducing agent such as sodium triacetoxyborohydride. The resulting mixture is stirred for several hours. The product, a compound of Formula 111 is isolated and purified.  
      Alternatively, when Y is —C(O)— or —S(O) 2 —, the transformation may be effected by alkylation. For example, a solution of a compound of Formula 109 and an amine base such as diisopropylethylamine in a nonpolar, aprotic solvent such as dichloromethane is added a compound having the formula Z-R 6  where R 6  is as described above and Z is a leaving group such as Br, Cl, mesylate, or tosylate. The resulting solution is stirred under nitrogen at room temperature or with heat for several hours. The product, a compound of Formula 111 is isolated and purified.  
      Preparation of Formula 113  
      Referring to Reaction Scheme 1, Step 6, to a solution of a compound of Formula 111 and an amine base such as diisopropylethylamine in a nonpolar, aprotic solvent such as dichloromethane is added an R 7  acyl chloride (such as Cl—C(O)—R 7  where R 7  is as described above). The resulting solution is stirred under nitrogen at room temperature for several hours. The product, a compound of Formula 113 is isolated and purified.  
      Optionally, any protecting groups on a compound of Formula 113 are then removed. For example, if R 6  comprises a protected amine wherein the protecting group is a Boc group, then the protecting group may be removed by treatment of a solution of a compound of Formula 113 in a nonpolar, aprotic solvent such as dichloromethane with trifluoroacetic acid, while maintaining the reaction at about room temperature. The reaction is monitored, e.g., by TLC. Upon completion, the product, a compound of Formula 115 is isolated and purified.  
      In certain compounds of the invention, a particular stereo configuration (such as the (R) isomer) may be preferred at the stereogenic center to which R 2  is attached. The optically active compound can be prepared by methods known in the art. For example, an amine of Formula 109 is dissolved in an inert organic solvent (such as IPA) and warmed to 60° C. In a separate vessel, a resolving agent (such as dibenzoyl-D-tartaric acid) is dissolved, preferably in the same warm solvent, and then quickly added (with agitation) to the warm amine solution. The reaction mixture is left to crystallize by cooling to room temperature over 16 hours under continuing agitation. The desired isomer, e.g., the (R) isomer, is isolated and purified.  
      For the sake of brevity in the remaining description of the synthesis of compounds of Formula I, it should be understood that either single isomer or a mixture of isomers may be employed to give the corresponding product.  
                 
 
 Preparation of Compounds of Formula 202 
 
      Referring to Reaction Scheme 2, to a solution of a compound of Formula 111 and an amine base such as diisopropylethylamine in a nonpolar, aprotic solvent such as dichloromethane is added a compound having the formula Cl—S(O) 2 —R 7a  or O—(S(O) 2 —R 7a ) 2  where R 7a  is as described above. The resulting solution is stirred under nitrogen at room temperature for several hours. The product, a compound of Formula 202 is isolated and purified.  
                 
 
 Preparation of Compounds of Formula 302 
 
      Referring to Reaction Scheme 3, to a solution of a compound of Formula 111 and an amine base such as diisopropylethylamine in a nonpolar, aprotic solvent such as dichloromethane is added a compound having the formula Z-R 3  where R 3  is as described above and Z is a leaving group (especially chloro or bromo). The resulting solution is stirred under nitrogen at room temperature or with heat for several hours. The product, a compound of Formula 302 is isolated and purified.  
      Alternatively, compounds of Formula 302 can be prepared via a reductive animation. For example, a solution of a compound of Formula 111 and an equivalent of a suitably protected aldehyde (see, for example, Seki et. al.  Chem. Pharm. Bull.  1996, 44, 2061) in dichloromethane is added a slight excess of a reducing agent, such as sodium triacetoxyborohydride. The resultant mixture is maintained at ambient temperature. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 302 is isolated and optionally purified.  
                 
 
 Preparation of Formula 403 
 
      Referring to Reaction Scheme 4, Step 1, to an optionally substituted compound of Formula 109 dissolved in a polar, aprotic solvent (such as DMF) in the presence of a base (such as potassium carbonate) is added one equivalent of an optionally substituted suitably protected aldehyde wherein such aldehyde further comprises a leaving group, preferably, a halide. The solution is heated at reflux, monitoring completion of the reaction (e.g., by TLC). The reaction mixture is cooled and the corresponding, optionally substituted compound of Formula 403 is isolated and purified.  
      Preparation of Formula 405  
      Referring to Reaction Scheme 4, Step 2, to an optionally substituted compound of Formula 403 in an inert solvent (such as dichloromethane) in the presence of about 1.5 molar equivalents of an amine base (such as triethylamine) is added about 1.5 molar equivalents of an R 9  acid chloride, such as, Cl—C(O)—R 9 , where R 9  is as described below. The reaction takes place, with stirring, at room temperature over a period of 4 to 24 hours. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 405 is isolated and purified.  
      Preparation of Formula 407  
      Referring to Reaction Scheme 4, Step 3, a solution of a compound of Formula 405 and an excess of ammonium acetate in acetic acid is heated at reflux for 1-4 hours. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 407 is isolated and purified.  
                 
 
 Preparation of Formula 503 
 
      Referring to Reaction Scheme 5, Step 1, a suspension of a compound of Formula 109, an alpha-haloketone reagent of the Formula R 10 (CO)CH 2 Z wherein Z is a leaving group (especially a halide), and about an equivalent of a base, such as potassium carbonate in a polar, aprotic solvent such as DMF is stirred at room temperature. The reaction is diluted with water and the resulting solid, a compound of Formula 503, is used in the subsequent step without further purification.  
      Preparation of Formula 505  
      Referring to Reaction Scheme 5, Step 2, a solution of the compound of Formula 503, about an equivalent of an amine base, such as triethylamine and about an equivalent of an acid chloride (such as a compound of Formula R 9 -COCl) in an organic solvent such as methylene chloride is stirred at room temperature for several hours. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 505 is isolated and purified.  
      Preparation of Formula 507  
      Referring to Reaction Scheme 5, Step 3, a solution of a compound of Formula 505 and an excess of ammonium acetate in acetic acid is heated at reflux using a Dean-Stark trap and condenser. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 507 is isolated and purified.  
      Optionally, when R 10  comprises a phthalimide protecting group, the protecting group is removed as follows. A solution of a compound of Formula 507 and an excess of anhydrous hydrazine in a polar, protic solvent such as ethanol is heated at reflux. The reaction is cooled to about 5° C. and any precipitate is filtered off. The filtrate is concentrated in vacuo and purified to yield the free amine. One of skill in the art will appreciate that other conditions may be used to remove other protecting groups.  
                 
 
 Preparation of Formula 603 
 
      Referring to Reaction Scheme 6, Step 1, reductive alkylation of amines of Formula 109 (prepared as described in WO 0130768) with an optionally substituted, aldehyde-containing carbamic acid ester (Seki et. al.  Chem. Pharm. Bull.  1996, 44, 2061) gives urethane intermediates. Removal of the Boc protecting group furnishes an amine of Formula 605.  
      More specifically, to a solution of a compound of Formula 109 and an equivalent of a suitably protected aldehyde (Seki et. al.  Chem. Pharm. Bull.  1996, 44, 2061) in dichloromethane is added a slight excess of a reducing agent, such as sodium triacetoxyborohydride. The resultant cloudy mixture is maintained at ambient temperature. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 603 is isolated and used in the subsequent step without purification.  
      Preparation of Formula 605  
      Referring to Reaction Scheme 6, Step 2, to a solution of a compound of Formula 603 in a nonpolar, aprotic solvent such as dichloromethane is added a strong acid such as trifluoroacetic acid. The resultant solution is maintained at ambient temperature overnight and concentrated under reduced pressure. The residue is isolated to give a compound of Formula 605 which was used in the subsequent step without purification.  
      Preparation of Formula 607  
      Referring to Reaction Scheme 6, Step 3, to a solution of a compound of Formula 605 in a nonpolar, aprotic solvent such as dichloromethane is added an excess, preferably about two equivalents of an amine base such as triethylamine, followed by about an equivalent or slight excess of an acid chloride of formula R 13 COCl. The resultant solution is stirred at ambient temperature for about 3 hours. Completion is monitored, e.g., by TLC. The corresponding compound of Formula 607 is isolated and purified.  
      Preparation of Formula 609  
      Referring to Reaction Scheme 6, Step 4, a solution of a compound of Formula 607 in an excess of phosphorus oxychloride is heated at reflux. After 8 hours, the reaction mixture is allowed to cool to ambient temperature and concentrated under reduced pressure. The corresponding compound of Formula 609 is isolated and purified.  
                 
 
 Preparation of Formula 609 
 
      As an alternative to Steps 3 and 4 of Reaction Scheme 6, acylation of primary amines of Formula 605, followed by acetic acid mediated cyclization, can proceed without isolation of the intermediate amides to provide the target compound of Formula 609. This route is shown in Reaction Scheme 7.  
      More specifically, to a solution of a compound of Formula 605 in a nonpolar, aprotic solvent such as dichloromethane is added an excess, preferably about two equivalents of an amine base, such as triethylamine, followed by about an equivalent of an acid chloride of the formula R 13 COCl. The resultant solution is stirred at ambient temperature for 2 hours, then evaporated under reduced pressure. The resultant solid is treated with glacial acetic acid, then the resultant suspension is heated at reflux for about 48 hours. The reaction is cooled to ambient temperature then evaporated under reduced pressure. The corresponding compound of Formula 609 is isolated and purified.  
                 
 
 Preparation of Compounds of Formula 803 
 
      Referring to Reaction Scheme 8, Step 1, a nonpolar, aprotic solvent, such as THF, and an excess of a solution of an optionally substituted vinyl magnesium bromide in a nonpolar, aprotic solvent (and more preferably, about three equivalents of a 1.0 M solution of an optionally substituted vinyl magnesium bromide in THF) is cooled to −78° C. while stirring under a nitrogen atmosphere. The mixture is treated dropwise with a solution of a compound of Formula 801 in a nonpolar, aprotic solvent, such as THF over about 30 min. After the mixture is stirred for 30 min at −78° C., the cooling bath is removed and the reaction mixture is warmed slowly to room temperature overnight (about 15 h). The product, a compound of Formula 803, is isolated and purified.  
      Preparation of Compounds of Formula 805  
      Referring to Reaction Scheme 8, Step 2, to a solution of a compound of Formula 803 in an anhydrous, nonpolar, aprotic solvent, such as acetonitrile under an inert atmosphere, such as argon, is added about an equivalent of a compound of the Formula R 1′ -I wherein R 1′  is an optionally susbituted vinyl, optionally susbituted aryl, or optionally susbituted heteroaryl, and a base such as triethylamine followed by palladium (II) acetate (preferably, about 0.025 equivalents). The resulting solution is heated to 80 □C. After about 15 h, the reaction mixture is allowed to cool to room temperature. The product, a compound of Formula 805, is isolated and immediately purified.  
      Preparation of Compounds of Formula 807  
      To a solution of a compound of Formula 805 in a nonpolar, aprotic solvent such as ethyl acetate under nitrogen is added 10 wt % palladium on carbon. The nitrogen is replaced with a balloon of hydrogen and the flask is purged. After 3 h, the reaction flask is purged with nitrogen and filtered through a pad of celite (rinsing with a solvent such as ethyl acetate). The product, a compound of Formula 807 is isolated and purified.  
                 
 
 Preparation of Compounds of Formula 903 
 
      Referring to Reaction Scheme 9, to a solution of a compound of Formula 901 (wherein Z is Cl when Y is —C(O)— or —S(O) 2 — and Z is Br when Y is not —C(O)— or —S(O) 2 —) in a nonpolar, aprotic solvent such as DMF are added a base such as triethylamine and an excess (preferably, about 1.5 equivalents) of imidazole followed by about an equivalent of tetrabutylammonium iodide. The resultant solution is heated to about 90 □C, stirred for about 18 h and allowed to cool to room temperature. The product, a compound of Formula 903, is isolated and purified.  
                 
 
 Preparation of Compounds of Formula 1003 
 
      Referring to Reaction Scheme 10, Step 1, to a solution of a compound of Formula 109 and an excess of an optionally substituted, aldehyde-containing carbamic acid ester such as ((S)-4-benzyloxycarbonylamino-1-formyl-butyl)-carbamic acid tert-butyl ester) in a nonpolar, aprotic solvent such as CH 2 Cl 2  is added sodium triacetoxyborohydride. The mixture is strirred overnight. The product, a compound of Formula 1003, is isolated and purified.  
      Preparation of Compounds of Formula 1005  
      Referring to Reaction Scheme 10, Step 2, to a solution of a compound of Formula 1003 in a nonpolar, aprotic solvent such as toluene is added a base such as triethylamine followed by dropwise addition of an excess of an acid chloride of the formula R 13 —COCl. The reaction mixture is heated to about 80 □C for about 18 h, then at reflux for about 4 h. The product, a compound of Formula 1005, is isolated and purified.  
      Preparation of Compounds of Formula 1007  
      Referring to Reaction Scheme 10, Step 3, a solution of a compound of Formula 1005 in a solvent such as CH 2 Cl 2 /TFA (preferably, about 4:1 CH 2 Cl 2 /TFA) is stirred at room temperature. The reaction mixture is concentrated under reduced pressure and the residue is diluted with a nonpolar, aprotic solvent such as CH 2 Cl 2  and washed with aqueous base. The aqueous layer is extracted with a nonpolar, aprotic solvent such as CH 2 Cl 2  and the combined extracts are dried, filtered and concentrated under reduced pressure. The residue is diluted with a nonpolar, aprotic solvent such as THF and aqueous base (preferably, saturated aqueous NaHCO 3 ). The mixture is stirred at room temperature for 10 days. The product, a compound of Formula 1007, is isolated and purified.  
                 
 
      Referring to Reaction Scheme 11, reductive amination of the primary amino group in compounds of Formula 109 with (2-oxo-ethyl)-carbamic acid tert-butyl ester gave the corresponding secondary amine. Acylation with acryloyl chloride followed by deprotection of the tertiary amide and base mediated cyclisation gave the desired diazepanones. If desired, further functionalization of the basic amine could be accomplished under conditions well known to those skilled in the art  
                 
 
      Referring to Reaction Scheme 12, reductive amination of the primary amino group in compounds of Formula 109 with (2-oxo-ethyl)-carbamic acid tert-butyl ester gave the corresponding secondary amine. Acylation with chloropivaloyl chloride followed by deprotection of the tertiary amide and base mediated cyclisation gave the desired diazepanones. If desired, further functionalization of the basic amine could be accomplished under conditions well known to those skilled in the art.  
                 
 
      Referring to Reaction Scheme 13, a compound of Formula 901, one-half molar equivalent of an optionally substituted piperazine or diazepam (as shown above, where R 32  is as described herein) and an excess of potassium carbonate are combined in an organic solvent (e.g., acetonitrile). The reaction takes place under a nitrogen atmosphere at elevated temperature (e.g., 100° C.) over a period of 8 hours, followed at a somewhat lower temperature (e.g., 60° C.) for a period of 5 days. The product, a compound of Formula 1303, is isolated and purified.  
      Optionally, in the event that R 32  is am amine protecting group, such as Boc, it may be removed by for example treatment with a 95/5 mixture of TFA/water followed by stirring at room temperature for 1 hour. The product, a compound of Formula 1303 wherein R 32  is hydrogen, can be isolated and purified. If desired, further functionalization of the basic amine could be accomplished under conditions well known to those skilled in the art.  
     Particular Processes and Last Steps  
      A compound of Formula I is optionally contacted with a pharmaceutically acceptable acid or base to form the corresponding acid or base addition salt.  
      A pharmaceutically acceptable acid addition salt of a compound of Formula I is optionally contacted with a base to form the corresponding free base of Formula I.  
      A pharmaceutically acceptable base addition salt of a compound of Formula I is optionally contacted with an acid to form the corresponding free acid of Formula I.  
     Particular Embodiments of Compounds of the Invention  
      X and Y  
      When considering the compounds of Formula I, X is optionally substituted alkylene, —C(O)—, or is absent; and Y is optionally substituted alkylene, —C(O)—, or is absent. In one embodiment, one of X and Y is absent and the other is optionally substituted alkylene (especially optionally substituted methylene). In another embodiment, both are absent.  
      R 1    
      When considering the compounds of Formula I, in one embodiment, R 1  is selected from hydrogen, optionally substituted C 1 -C 8  alkyl-, optionally substituted aryl-, optionally substituted heteroaryl-, optionally substituted aryl-C 1 -C 4 -alkyl-, and optionally substituted heteroaryl-C 1 -C 4 -alkyl-(more preferably optionally substituted aryl and optionally substituted aryl-C 1 -C 4 -alkyl-). In a more particular embodiment R 1  is selected from hydrogen, optionally substituted C 1 -C 4  alkyl-, optionally substituted phenyl-C 1 -C 4 -alkyl-, optionally substituted naphthalenylmethyl-, optionally substituted phenyl-, and naphthyl-. Even more particularly, R 1  is optionally substituted phenyl-C 1 -C 4 -alkyl-, optionally substituted heteroaryl-C 1 -C 4 -alkyl-, or naphthalenylmethyl-.  
      Yet more particularly, R 1  is naphthyl-, phenyl-, bromophenyl-, chlorophenyl-, methoxyphenyl-, ethoxyphenyl-, tolyl-, dimethylphenyl-, chorofluorophenyl-, methylchlorophenyl-, ethylphenyl-, phenethyl-, benzyl-, chlorobenzyl-, methylbenzyl-, methoxybenzyl-, cyanobenzyl-, hydroxybenzyl-, dichlorobenzyl-, dimethoxybenzyl-, or naphthalenylmethyl-. More suitably, R 1  is benzyl-, cyanobenzyl-, metlioxybenzyl-, or naphthalenylmethyl-. Most particularly, R 1  is benzyl-.  
      R 2  and R 2′   
      When considering the compounds of Formula I and as will be appreciated by those skilled in the art, the compounds described herein possess a potentially chiral center at the carbon to which R 2  and R 2′  are attached. The R 2  and R 2′  groups may be the same or different; if different, the compound is chiral (i.e., has a stereogenic center). When R 2  and R 2′  are different, in particular embodiments R 2′  is hydrogen and R 2  is other than hydrogen. The invention contemplates the use of pure enantiomers and mixtures of enantiomers, including racemic mixtures, although the use of a substantially optically pure enantiomer will generally be preferred. The term “substantially pure” means having at least about 95% chemical purity with no single impurity greater than about 1%. The term “substantially optically pure” or “enantiomerically pure” means having at least about 97.5% enantiomeric excess. In a particular embodiment, the stereogenic center to which R 2  and R 2′  are attached is of the R configuration.  
      When considering the compounds of Formula I, R 2  and R 2′  are independently chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-.  
      In one embodiment, R 2  is optionally substituted C 1 -C 4  alkyl-, and R 2′  is hydrogen or optionally substituted C 1 -C 4  alkyl-. More suitably, R 2′  is hydrogen and R 2  is optionally substituted C 1 -C 4  alkyl-. In a most particular embodiment R 2  is chosen from methyl-, ethyl-, propyl (particularly, c-propyl or i-propyl), butyl (particularly, t-butyl), aminobutyl-, (CBZ)aminobutyl-, cyclohexylmethyl-, benzyloxymethyl-, methylsulfanylethyl-, methylsulfanylmethyl-, and hydroxymethyl-, and R 2′  is hydrogen. Especially chosen embodiments are when R 2′  is hydrogen and R 2  is ethyl or propyl (particularly, c-propyl or i-propyl). Even more particularly, R 2  is i-propyl. Yet more particularly, the stereogenic center to which R 2  and R 2′  is attached is of the R configuration.  
      In one embodiment, if either R 2  or R 2′  is hydrogen, then the other is not hydrogen. In another embodiment, both R 2  and R 2′  are hydrogen.  
      In another embodiment, R 2  and R 2′  taken together form a 3- to 7-membered ring which may optionally be substituted one or more of the following groups: hydroxyl, halogen (particularly chloro and fluoro), optionally substituted C 1 -C 4  alkyl-(particularly methyl-), C 1 -C 4  alkoxy (particularly methoxy), cyano, amino, substituted amino, or carbamyl.  
      R 2  Taken Together with R 3    
      In another embodiment, R 2  and R 3  taken together form a 5- to 12-membered ring which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring and may optionally be substituted one or more of the following groups: hydroxyl, halogen (particularly chloro and fluoro), optionally substituted C 1 -C 4  alkyl-(particularly methyl-), C 1 -C 4  alkoxy (particularly methoxy), cyano, amino, substituted amino, oxo, or carbamyl; and R 2′  is as defined above. In a particular embodiment, R 3  is —C(O)R 7  and the 5- to 12-membered ring is formed between R 2  and R 7 .  
      In a particular embodiment, R 2  and R 3  taken together form an optionally substituted ring of the formula:  
                 
 
 wherein R 41  and R 41′  are independently chosen from hydrogen, alkyl, aryl, aralkyl, heteroaryl, substituted alkyl, substituted aryl, substituted aralkyl, and substituted heteroaryl; m is 0, 1, 2, or 3; and X, Y, R 3 , and R 2′  are as defined above. According to this embodiment, R 6  is chosen from hydrogen, optionally substituted acyl, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-. In a more particular embodiment, R 41  is hydrogen. In another particular embodiment, both R 41  and R 41′  are hydrogen. In another embodiment, R 6  is optionally substituted aralkyl (especially benzyl) or optionally substituted acyl (especially p-methyl-benzoyl). See, e.g., U.S. Ser. No. 60/414,756, which is incorporated herein by reference for all purposes. 
 
      In another embodiment, R 2  and R 3  taken together form an optionally substituted ring of the formula:  
                 
 
 wherein R 1 , R 4 , R 5 , R 6 , R 2′ , X, and Y are as defined above; R 51  and R 51′  are independently chosen from hydrogen, alkyl, aryl, aralkyl, heteroaryl, substituted alkyl, substituted aryl, substituted aralkyl and substituted heteroaryl; W is a covalent bond, CR′R″ or NR′″; R′ and R″ are independently chosen from hydrogen, hydroxy, amino, optionally substituted aryl, optionally substituted alkylamino, optionally substituted alkyl and optionally substituted alkoxy; and R′″ is chosen from hydrogen, optionally substituted alkyl, optionally substituted aryl, optionally substituted aralkyl, optionally substituted heteroaryl, and optionally substituted heteroaralkyl. 
 
      In a particular embodiment, R 51  is hydrogen or optionally substituted lower alkyl; more particularly, R 51  is hydrogen. In another embodiment, R 51′  is hydrogen or optionally substituted lower alkyl; more particularly, R 51′  is hydrogen.  
      In one embodiment, R 6  is optionally substituted aryl or optionally substituted aralkyl; more particularly, R 6  is optionally substituted phenyl, benzyl or methyl-benzyl (especially, benzyl or methyl-benzyl).  
      In one embodiment, W is CR′R″ where R′ and/or R″ are hydrogen. In another embodiment, W is NR′″ where R′″ is hydrogen or optionally substituted alkyl. More particularly, R′″ is hydrogen or optionally substituted amino-lower alkyl. See, e.g., U.S. Ser. No. 60/398,224, which is incorporated herein by reference for all purposes.  
      R 4  and R 5    
      In a particular embodiment, R 4  and R 5  are independently chosen from hydrogen, hydroxyl, halo (particularly chloro and fluoro), optionally substituted lower alkyl (particularly methyl), optionally substituted lower alkoxy (particularly methoxy), cyano optionally substituted amino, carbamyl, aryloxy, heteroaryloxy, heteroaryl, and optionally substituted N-heterocyclyl. More particularly, R 5  is hydrogen, lower alkyl (particulary, methyl) or halo; and R 4  is hydrogen, halo, optionally substituted lower alkyl (particularly, methyl or trifluoromethyl), optionally substituted lower alkoxy (particularly, methoxy), cyano, substituted amino, carbamyl, aryloxy (particularly, phenoxy), heteroaryloxy (particularly, pyridinyloxy), heteroaryl (particularly, 2-oxo-2H-pyridinyl), or optionally substituted N-heterocyclyl (particularly, morpholinyl or piperazinyl).  
      In another embodiment, R 4  and R 5  taken together with the carbons to which they are attached form an optionally substituted 5-, 6- or 7-membered non-aromatic ring. In a more particular embodiment, the non-aromatic ring is alicyclic. In another embodiment, the non-aromatic ring is heterocyclic. The non-aromatic ring may be substituted with one or more of the following substituents: halo, optionally substituted lower-alkyl-, optionally substituted lower-alkoxy, and/or hydroxy.  
      R 3    
      When considering the compounds of Formula I, R 3  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, —C(O)—R 7 , and —S(O) 2 —R 7a . In a particular embodiment, R 3  is —C(O)—R 7 . In another particular embodiment, R 3  is —S(O) 2 —R 7a . In another embodiment, R 3  is hydrogen.  
      Suitably, R 3  is chosen from C 1 -C 13  alkyl-; substituted lower-alkyl-; phenyl-; naphthyl-; phenyl substituted with cyano, halo, lower-alkyl-, lower-alkoxy, nitro, methylenedioxy, or trifluoromethyl-; biphenylyl-, benzyl and heterocyclyl-. Most suitably, R 3  is chosen from phenyl substituted with one or more halo, methyl-, cyano, trifluoromethyl-, trifluoromethoxy, carboxy, or methoxycarbonyl groups; piperidinyl-; and naphthyl-. Even more suitably, R 3  is halophenyl-, methylhalophenyl-, polyhalophenyl-, tolyl-, dimethylphenyl-, methoxyphenyl-, dimethoxyphenyl-, cyanophenyl-, trifluoromethylphenyl-, trifluorometoxyphenyl-, bis(trifluoromethyl)phenyl-, carboxyphenyl-, t-butylphenyl-, methoxycarbonylphenyl-, piperidinyl-, and naphthyl-.  
      R 6    
      When considering the compounds of Formula I, R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-.  
      In one embodiment, R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-. More suitably, R 6  is R 12 -alkylene-, and R 12  is chosen from alkoxy, amino, alkylamino, dialkylamino, carboxy, guanidine, hydroxyl-, and N-heterocyclyl-.  
      In a more particular embodiment, R 6  is selected from optionally substituted lower-alkyl-, optionally substituted cyclohexyl-; phenyl substituted with hydroxy, lower-alkoxy or lower-alkyl-; benzyl-; heteroarylmethyl-; heteroarylethyl-; and heteroarylpropyl-.  
      In a most particular embodiment, R 6  is chosen from methyl-, ethyl-, propyl-, butyl-, cyclohexyl-, carboxyethyl-, carboxymethyl-, methoxyethyl-, hydroxyethyl-, hydroxypropyl-, dimethylaminoethyl-, dimethylaminopropyl-, diethylaminoethyl-, diethylaminopropyl-, aminopropyl-, methylaminopropyl-, 2,2-dimethyl-3-(dimethylamino)propyl-, 1-cyclohexyl-4-(diethylamino)butyl-, aminoethyl-, aminobutyl-, aminopentyl-, aminohexyl-, aminoethoxyethyl-, isopropylaminopropyl-, diisopropylaminoethyl-, 1-methyl-4-(diethylamino)butyl-, (t-Boc)aminopropyl-, hydroxyphenyl-, benzyl-, methoxyphenyl-, methylmethoxyphenyl-, dimethylphenyl-, tolyl-, ethylphenyl-, (oxopyrrolidinyl)propyl-, (methoxycarbonyl)ethyl-, benzylpiperidinyl-, pyridinylethyl-, pyridinylmethyl-, morpholinylethyl morpholinylpropyl-, piperidinyl-, azetidinylmethyl-, azetidinylethyl-, azetidinylpropyl-, pyrrolidinylmethyl-, pyrrolidinylethyl-, pyrrolidinylpropyl-, piperidinylmethyl-, piperidinylethyl-, imidazolylpropyl-, imidazolylethyl-, (ethylpyrrolidinyl)methyl-, (methylpyrrolidinyl)ethyl-, (methylpiperidinyl)propyl-, (methylpiperazinyl)propyl-, guanidino-ethyl-, guanidino-propyl-, furanylmethyl and indolylethyl-.  
      R 3  Taken Together With R 6    
      When considering the compounds of Formula I, in one embodiment, R 3  taken together with R 6 , and the nitrogen to which they are bound, form an optionally substituted 5- to 12-membered nitrogen-containing heterocycle, which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring.  
      In a particular embodiment, R 3  taken together with R 6  and the nitrogen to which they are bound, forms an optionally substituted imidazolinyl ring of the formula:  
                 
 
 wherein 
 
      R 9  is chosen from hydrogen, optionally substituted C 1 -C 8  alkyl-, optionally substituted aryl-, optionally substituted aryl-C 1 -C 4 -alkyl-, optionally substituted heteroaryl-C 1 -C 4 -alkyl-, optionally substituted aryl-C 1 -C 4 -alkoxy, optionally substituted heteroaryl-C 1 -C 4 -alkoxy, and optionally substituted heteroaryl-; and  
      R 10  and R 11  are independently hydrogen, optionally substituted C 1 -C 8  alkyl-, optionally substituted aryl-, or optionally substituted aryl-C 1 -C 4 -alkyl-.  
      According to one embodiment, R 9  is phenyl substituted with C 1 -C 4 -alkyl-, C 1 -C 4 -alkoxy-, and/or halo; phenyl-; benzyl-; thiophenyl-; or thiophenyl-substituted with C 1 -C 4 -alkyl-, C 1 -C 4 -alkoxy-, and/or halo. More suitably, R 9  is phenyl substituted with one or more halo and/or methyl.  
      According to another embodiment, R 11  is hydrogen and R 10  is substituted C 1 -C 4  alkyl-. More suitably, R 11  is hydrogen and R 10  is aminomethyl-, aminoethyl-, aminopropyl-, acetylamiino-methyl-, acetylaminoethyl-, benzyloxycarbonylamino-methyl-or benzyloxycarbonylamino-ethyl-. See, e.g., PCT/US03/14787, which is incorporated herein by reference.  
      In another particular embodiment, R 3  taken together with R 6  forms an optionally substituted imidazolinyl ring of the formula:  
                 
 
      wherein,  
      R 13  is chosen from hydrogen, optionally substituted C 1 -C 8  alkyl-, optionally substituted aryl-, optionally substituted aryl-C 1 -C 4 -alkyl-, optionally substituted heteroaryl-, optionally substituted heteroaryl-C 1 -C 4 -alkyl-; and  
      R 15 , R 15′ , R 16,  and R 16′  are independently chosen from hydrogen, optionally substituted C 1 -C 8  alkyl-, optionally substituted aryl-, and optionally substituted aryl-C 1 -C 4 -alkyl-.  
      In one embodiment, R 13  is methylenedioxyphenyl-; phenyl-; phenyl substituted with C 1 -C 4  alkyl-, C 1 -C 4  alkoxy-, and/or halo; benzyl-; thienyl substituted with C 1 -C 4  alkyl; benzyl; thiophenyl-; or thiophenyl-substituted with C 1 -C 4 -alkyl-, C 1 -C 4 -alkoxy-, and/or halo. More suitably, R 13  is methylenedioxyphenyl-; phenyl-; tolyl-; methoxyphenyl-; or halomethylphenyl-.  
      In one embodiment, R 15 , R 15′ , R 16,  and R 16′  are independently hydrogen or optionally substituted C 1 -C 4  alkyl-. More suitably, R 16  and R 16′  are hydrogen.  
      In another embodiment, R 3  taken together with R 6  forms an optionally substituted diazepinone ring of the formula:  
                 
 
 wherein A and B are each independently chosen from C(R 20 )(R 21 ), N(R 22 ), O or S, wherein R 20  and R 21  are each independently selected from H, optionally substituted alkyl optionally substituted aryl and optionally substituted heteroaryl; and R 22  is H, optionally substituted alkyl, optionally substituted aralkyl, optionally substituted heteroaralkyl, optionally substituted alkylcarbonyl, optionally substituted arylcarbonyl, optionally substituted heteroarylcarbonyl, optionally substituted aralkylcarbonyl, optionally substituted heteroaralkylcarbonyl, optionally substituted alkoxycarbonyl, optionally substituted aryloxycarbonyl, optionally substituted heteroaryloxycarbonyl, optionally substituted aralkyloxycarbonyl, optionally substituted heteroaralkyloxycarbonyl. In a more particular embodiment, the diazepinone ring is further substituted with one or more of the following groups: optionally substituted alkyl, optionally substituted aryl, optionally substituted aralkyl, optionally substituted he heteroaryl, and optionally substituted heteroaralkyl. 
 
      In yet another embodiment of the compounds of Formula I, one of A or B is C(R 20 )(R 21 ), wherein R 20  and R 21 ) are each independently selected from H or C 1 -C 4  alkyl, and the other of A or B is N(R 22 ), where R 22  is H, C 1 -C 4  alkyl, optionally substituted aralkyl, optionally substituted heteroaralkyl, C 1 -C 6  alkylcarbonyl, optionally substituted arylcarbonyl, optionally substituted heteroarylcarbonyl, optionally substituted aralkylcarbonyl, optionally substituted heteroaralkylcarbonyl, C 1 -C 6  alkoxycarbonyl, optionally substituted aryloxycarbonyl, optionally substituted heteroaryloxycarbonyl, optionally substituted aralkyloxycarbonyl, optionally substituted heteroaralkyloxycarbonyl, where the optionally substituted aryl or heteroaryl groups or moieties are unsubstituted or substituted with one or more substituents selected from C 1 -C 4  alkyl, C 1 -C 4  haloalkyl, C 1 -C 4  alkoxy, C 1 -C 4  haloalkoxy, amino, C 1 -C 4  alkylamino, di-C 1 -C 4  alkylamino, carboxy, C 1 -C 4  alkylcarbonyloxy, C 1 -C 4  alkoxycarbonyl, carboxamido, C 1 -C 4  alkylcarboxamido, aminocarbonyl, C 1 -C 4  alkylaminocarbonyl, di-C 1 -C 4  alkylaminocarbonyl, cyano, C 1 -C 4  alkylcarbonyl, halogen, hydroxyl, mercapto and nitro. In another embodiment, A is C(R 20 )(R 21 ), wherein R 20  and R 21  are each H or C 1 -C 4  alkyl, and B is N(R 22 ), where R 22  is H, C 1 -C 4  alkyl, aralkyl, heteroaralkyl, C 1 -C 6  alkylcarbonyl, arylcarbonyl, heteroarylcarbonyl. In specific embodiments of the compounds of Formula I, A is CH 2 , and B is N(R 22 ), where R 22  is H, methyl, benzyl or acetyl (—C(O)methyl). See, e.g., U.S. Ser. No. 60/435,001, which is incorporated herein by reference for all purposes.  
      In another embodiment, R 3  taken together with R 6  forms an optionally substituted piperazine- or diazepam of the formula:  
                 
 
 R 31  and R 32  are independently chosen from hydrogen, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted aralkyl, and optionally substituted heteroaralkyl; and n is 1 or 2. More particularly, R 31  is aryl (preferably phenyl), substituted aryl (preferably lower alkyl-, lower alkoxy-, and/or halo-substituted phenyl), aralkyl (preferably benzyl and phenylvinyl), heteroaralkyl, substituted aralkyl (preferably substituted benzyl and substituted phenylvinyl), or substituted heteroaralkyl; R 32  is hydrogen; and n is 1. See, e.g., U.S. Ser. No. 60/404,864, which is incorporated herein by reference. 
 
 R 7  
 
      When considering the compounds of Formula I, in a particular embodiment R 7  is selected from hydrogen, optionally substituted alkyl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, optionally substituted heteroaryl-, optionally substituted aryl-, R 8 O— and R 14 —NH—, wherein R 8  is chosen from optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, and optionally substituted heteroaralkyl-; and R 14  is hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, or optionally substituted heteroaralkyl-.  
      In a more particular embodiment, when R 7  is not R 14 NH— or R 8 O—, R 7  is chosen from optionally substituted alkyl-; aryl-(including phenyl-, biphenyl-, and naphthyl-); substituted aryl-(including phenyl substituted with one or more cyano, halo, lower-alkyl-, lower-alkoxy, hydroxy-loweralkyl-, nitro, carboxy, methylenedioxy, trifluoromethoxy, or trifluoromethyl-); benzyl-; and optionally substituted heteroaryl-.  
      In a most particular embodiment, when R 7  is not R 14 NH— or R 8 O—, R 7  is chosen from ethyl-, propyl-, chloropropyl-, butoxy, heptyl-, butyl-, octyl-, tridecanyl-, (ethoxycarbonyl)ethyl-, dimethylaminoethyl-, dimethylaminoethyl-, phenyl-, naphthyl-, halophenyl-, polyhalophenyl-, cyanophenyl-, hydroxymethylphenyl-, halo(trifluoromethyl)phenyl-, chlorophenoxymethyl-, methoxyphenyl-, carboxyphenyl-, ethylphenyl-, tolyl-,hydroxymethylphenyl-; ethylphenyl-; biphenylyl-, methylenedioxyphenyl-, methylsulfonylphenyl-, methoxychlorophenyl-, chloronaphthyl-, acetylphenyl-, methylhalophenyl-, trifluoromethylphenyl-, trifluoromethoxyphenyl-, butylphenyl-, pentylphenyl-, methylnitrophenyl-, phenoxymethyl-, dimethoxyphenyl-, phenylvinyl-, nitrochlorophenyl-, nitrophenyl-, dinitrophenyl-, bis(trifluoromethyl)phenyl-, benzyloxymethyl-, benzyl-, furanyl-, benzofuranyl-, pyridinyl-, pyridyl-, indolyl-, methylpyridinyl-, methylpyridyl-, (3-carbamoyl)pyridinyl-[nicotinamide], 3-carbamoyl-6-methylpyridinyl-, quinolinyl-, picolinyl-, pyrazolyl-, pyrazinyl-, methylpyrazinyl-, morpholinomethyl-, methylsulfanylmethyl-, methoxymethyl-, imidazolyl-; isoxazolyl-, methyl-isoxazolyl-; benzothiadiazolyl-; methylenedioxyphenyl-, thienyl-, methylthienyl-, methyl-nicotinamidyl-; methyl-pyrazinyl; benzodioxolyl; and methyl-thiophenyl-.  
      More suitably, R 7  is tolyl-, halophenyl-, halomethylphenyl-, hydroxymethylphenyl-, methylenedioxyphenyl-, formylphenyl or cyanophenyl-.  
      In another particular embodiment, when R 7  is R 14 NH—, R 14  is chosen from lower-alkyl-; cyclohexyl-; phenyl-; and phenyl substituted with halo, lower-alkyl-, loweralkoxy, or lower-alkylsulfanyl-.  
      In another particular embodiment, when R 7  is R 14 NH—, R 14  is isopropyl-, butyl-cyclohexyl-, phenyl-, bromophenyl-, dichlorophenyl-, methoxyphenyl-, ethylphenyl-, tolyl-, trifluoromethylphenyl or methylthiophenyl-.  
      In a particular embodiment, when R 7  is R 8 O—, R 8  is chosen from lower-alkyl-; cyclohexyl-; phenyl-; and phenyl substituted with halo, lower-alkyl-, loweralkoxy, or lower-alkylsulfanyl-.  
      In a most particular embodiment, when R 7  is R 8 O—, R 8  is isopropyl-, butyl-, cyclohexyl-, phenyl-, bromophenyl-, dichlorophenyl-, methoxyphenyl-, ethylphenyl-, tolyl-, trifluoromethylphenyl or methylthiophenyl-.  
      R 7a    
      In one embodiment, R 7a  is chosen from optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, and R 14 —NH—. More particularly, R 7a  is chosen from C 1 -C 13  alkyl-; phenyl-; naphthyl-; phenyl substituted with cyano, halo, lower-alkyl-, lower-alkoxy, nitro, methylenedioxy, or trifluoromethyl-; biphenylyl and heteroaryl-. More suitably, R 7a  is chosen from phenyl substituted with halo, lower-alkyl-, lower-alkoxy, cyano, nitro, methylenedioxy, or trifluoromethyl-; and naphthyl-.  
      Particular Subgenus  
      In a particular subgenus of compounds of Formula I,  
      X is absent;  
      Y is absent;  
      R 1  is optionally substituted aryl-C 1 -C 4 -alkyl-, optionally substituted heteroaryl-C 1 -C 4 -alkyl-, or naphthalenylmethyl;  
      R 2  is optionally substituted C 1 -C 4 -alkyl-;  
      R 2′  is hydrogen;  
      R 4  is methyl or phenyl;  
      R 5  is hydrogen or methyl;  
      and  
      R 3  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaryl-, optionally substituted heteroaralkyl-, —C(O)—R 7 , and —S(O) 2 —R 7a ; and R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-;  
      or R 3  taken together with R 6 , and the nitrogen to which they are bound, form an optionally substituted 5- to 12-membered nitrogen-containing heterocycle, which optionally incorporates from one to two additional heteroatoms, selected from N, O, and S in the heterocycle ring.  
      In a particular subgenus of compounds of Formula I,  
      X, Y, R 1 , R 2 , R 2′ , R 4 , and R 5  are as defined above;  
      R 3  and R 6  together with the nitrogen to which they are bound form an optionally substituted imidzole ring.  
      In a particular subgenus of compounds of Formula I,  
      X, Y, R 1 , R 2 , R 2′ , R 4 , and R 5  are as defined above;  
      R 3  and R 6  together with the nitrogen to which they are bound form an optionally substituted imidzoline ring.  
      In a particular subgenus of compounds of Formula I,  
      X, Y, R 1 , R 2 , R 2′ , R 4 , and R 5  are as defined above;  
      R 3  is —C(O)R 7 ;  
      R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl- and  
      R 7  is selected from hydrogen, optionally substituted alkyl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, optionally substituted heteroaryl-, optionally substituted aryl-, R 8 O— and R 14 —NH—, wherein R 8  is chosen from optionally substituted alkyl and optionally substituted aryl and R 14  is chosen from hydrogen, optionally substituted alkyl and optionally substituted aryl.  
      More particularly, X, Y, R 1 , R 2 , R 2′ , R 3 , R 4 , and R 5  are as defined above;  
      R 6  is R 12 -alkylene-, and R 12  is chosen from alkoxy, amino, alkylamino, dialkylamino, carboxy, hydroxyl-, and N-heterocyclyl-(especially, R 6  is selected from optionally substituted lower-alkyl-, optionally substituted cyclohexyl-; phenyl substituted with hydroxy, lower-alkoxy or lower-alkyl-; benzyl-; heteroarylmethyl-; heteroarylethyl-; heteroarylpropyl-);  
      and  
      R 7  is selected from hydrogen, optionally substituted alkyl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, optionally substituted heteroaryl-, optionally substituted aryl-, R 8 O— and R 14 —NH—, wherein R 8  is chosen from optionally substituted alkyl and optionally substituted aryl and R 14  is chosen from hydrogen, optionally substituted alkyl and optionally substituted aryl.  
      In a particular subgenus of compounds of Formula I,  
      X, Y, R 1 , R 2 , R 2′ , R 3 , R 4 , and R 5  are as defined above;  
      R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl- and  
      and  
      R 7  is selected from optionally substituted alkyl-; aryl-; substituted aryl-; benzyl-; and optionally substituted heteroaryl-.  
      In a particular subgenus of compounds of Formula I,  
      X, Y, R 1 , R 2 , R 2′ , R 3 , R 4 , R 5  ad R 6  are as defined above; and  
      R 7  is tolyl-, halophenyl-, halomethylphenyl-, hydroxymethylphenyl-, methylenedioxyphenyl-, formylphenyl or cyanophenyl-.  
      In a particular subgenus of compounds of Formula I wherein R 3  is —NR 6 (SO 2 R 7a )  
      X, Y, R 1 , R 2 , R 2′ , R 4 , and R 5  are as defined above;  
      R 3  is —S(O) 2 R 7a ;  
      R 6  is chosen from hydrogen, optionally substituted alkyl-, optionally substituted aryl-, optionally substituted aralkyl-, optionally substituted heteroaralkyl-, and optionally substituted heterocyclyl-and  
      R 7a  is chosen from phenyl substituted with halo, lower-alkyl-, lower-alkoxy, cyano, nitro, methlenedixoy, or trifluoromethyl-; and naphthyl-.  
      Particular compounds include:  
      N-(3-Amino-propyl)-N-[1-(3-benzyl-6-methyl-4-oxo-4H-pyran-2-yl)-2-methyl-propyl]-4-methyl-benzamide.  
     Utility, Testing and Administration  
      General Utility  
      Once made, the compounds of the invention find use in a variety of applications involving alteration of mitosis. As will be appreciated by those skilled in the art, mitosis may be altered in a variety of ways; that is, one can affect mitosis either by increasing or decreasing the activity of a component in the mitotic pathway. Stated differently, mitosis maybe affected (e.g., disrupted) by disturbing equilibrium, either by inhibiting or activating certain components. Similar approaches may be used to alter meiosis.  
      In a particular embodiment, the compounds of the invention are used to inhibit mitotic spindle formation, thus causing prolonged cell cycle arrest in mitosis. By “inhibit” in this context is meant decreasing or interfering with mitotic spindle formation or causing mitotic spindle dysfunction. By “mitotic spindle formation” herein is meant organization of microtubules into bipolar structures by mitotic kinesins. By “mitotic spindle dysfunction” herein is meant mitotic arrest and monopolar spindle formation.  
      The compounds of the invention are useful to bind to, and/or inhibit the activity of, a mitotic kinesin, KSP. In one embodiment, the KSP is human KSP, although the compounds may be used to bind to or inhibit the activity of KSP kinesins from other organisms. In this context, “inhibit” means either increasing or decreasing spindle pole separation, causing malformation, i.e., splaying, of mitotic spindle poles, or otherwise causing morphological perturbation of the mitotic spindle. Also included within the definition of KSP for these purposes are variants and/or fragments of KSP. See U.S. Pat. No. 6,437,115, hereby incorporated by reference in its entirety. The compounds of the invention have been shown to have specificity for KSP. However, the present invention includes the use of the compounds to bind to or modulate other mitotic kinesins.  
      The compounds of the invention are used to treat cellular proliferation diseases. Such disease states which can be treated by the compounds, compositions and methods provided herein include, but are not limited to, cancer (further discussed below), autoimmune disease, fungal disorders, arthritis, graft rejection, inflammatory bowel disease, cellular proliferation induced after medical procedures, including, but not limited to, surgery, angioplasty, and the like. Treatment includes inhibiting cellular proliferation. It is appreciated that in some cases the cells may not be in an abnormal state and still require treatment. Thus, in one embodiment, the invention herein includes application to cells or individuals afflicted or subject to impending affliction with any one of these disorders or states.  
      The compounds, compositions and methods provided herein are particularly deemed useful for the treatment of cancer including solid tumors such as skin, breast, brain, cervical carcinomas, testicular carcinomas, etc. More particularly, cancers that may be treated by the compounds, compositions and methods of the invention include, but are not limited to: Cardiac: sarcoma (angiosarcoma, fibrosarcoma, rhabdomyosarcoma, liposarcoma), myxoma, rhabdomyoma, fibroma, lipoma and teratoma; Lung: bronchogenic carcinoma (squamous cell, undifferentiated small cell, undifferentiated large cell, adenocarcinoma), alveolar (bronchiolar) carcinoma, bronchial adenoma, sarcoma, lymphoma, chondromatous hamartoma, mesothelioma; Gastrointestinal: esophagus (squamous cell carcinoma, adenocarcinoma, leiomyosarcoma, lymphoma), stomach (carcinoma, lymphoma, leiomyosarcoma), pancreas (ductal adenocarcinoma, insulinoma, glucagonoma, gastrinoma, carcinoid tumors, vipoma), small bowel (adenocarcinoma, lymphoma, carcinoid tumors, Karposi&#39;s sarcoma, leiomyoma, hemangioma, lipoma, neurofibroma, fibroma), large bowel (adenocarcinoma, tubular adenoma, villous adenoma, hamartoma, leiomyoma); Genitourinary tract: kidney (adenocarcinoma, Wilm&#39;s tumor (nephroblastoma), lymphoma, leukemia), bladder and urethra (squamous cell carcinoma, transitional cell carcinoma, adenocarcinoma), prostate (adenocarcinoma, sarcoma), testis (seminoma, teratoma, embryonal carcinoma, teratocarcinoma, choriocarcinoma, sarcoma, interstitial cell carcinoma, fibroma, fibroadenoma, adenomatoid tumors, lipoma); Liver: hepatoma (hepatocellular carcinoma), cholangiocarcinoma, hepatoblastoma, angiosarcoma, hepatocellular adenoma, hemangioma; Bone: osteogenic sarcoma (osteosarcoma), fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma, Ewing&#39;s sarcoma, malignant lymphoma (reticulum cell sarcoma), multiple myeloma, malignant giant cell tumor chordoma, osteochronfroma (osteocartilaginous exostoses), benign chondroma, chondroblastoma, chondromyxofibroma, osteoid osteoma and giant cell tumors; Nervous system: skull (osteoma, hemangioma, granuloma, xanthoma, osteitis deformans), meninges (meningioma, meningiosarcoma, gliomatosis), brain (astrocytoma, medulloblastoma, glioma, ependymoma, germinoma (pinealoma), glioblastoma multiform, oligodendroglioma, schwannoma, retinoblastoma, congenital tumors), spinal cord neurofibroma, meningioma, glioma, sarcoma); Gynecological: uterus (endometrial carcinoma), cervix (cervical carcinoma, pre-tumor cervical dysplasia), ovaries (ovarian carcinoma (serous cystadenocarcinoma, mucinous cystadenocarcinoma, unclassified carcinoma), granulosa-thecal cell tumors, Sertoli-Leydig cell tumors, dysgerminoma, malignant teratoma), vulva (squamous cell carcinoma, intraepithelial carcinoma, adenocarcinoma, fibrosarcoma, melanoma), vagina (clear cell carcinoma, squamous cell carcinoma, botryoid sarcoma (embryonal rhabdomyosarcoma), fallopian tubes (carcinoma); Hematologic: blood (myeloid leukemia (acute and chronic), acute lymphoblastic leukemia, chronic lymphocytic leukemia, myeloproliferative diseases, multiple myeloma, myelodysplastic syndrome), Hodgkin&#39;s disease, non-Hodgkin&#39;s lymphoma (malignant lymphoma); Skin: malignant melanoma, basal cell carcinoma, squamous cell carcinoma, Karposi&#39;s sarcoma, moles dysplastic nevi, lipoma, angioma, dermatofibroma, keloids, psoriasis; and Adrenal glands: neuroblastoma. Thus, the term “cancerous cell” as provided herein, includes a cell afflicted by any one of the above identified conditions.  
      Testing  
      For assay of KSP-modulating activity, generally either KSP or a compound according to the invention is non-diffusably bound to an insoluble support having isolated sample receiving areas (e.g., a microtiter plate, an array, etc.). The insoluble support may be made of any composition to which the sample can be bound, is readily separated from soluble material, and is otherwise compatible with the overall method of screening. The surface of such supports may be solid or porous and of any convenient shape. Examples of suitable insoluble supports include microtiter plates, arrays, membranes and beads. These are typically made of glass, plastic (e.g., polystyrene), polysaccharides, nylon or nitrocellulose, Teflon™, etc. Microtiter plates and arrays are especially convenient because a large number of assays can be carried out simultaneously, using small amounts of reagents and samples. The particular manner of binding of the sample is not crucial so long as it is compatible with the reagents and overall methods of the invention, maintains the activity of the sample and is nondiffusable. Particular methods of binding include the use of antibodies (which do not sterically block either the ligand binding site or activation sequence when the protein is bound to the support), direct binding to “sticky” or ionic supports, chemical crosslinking, the synthesis of the protein or agent on the surface, etc. Following binding of the sample, excess unbound material is removed by washing. The sample receiving areas may then be blocked through incubation with bovine serum albumin (BSA), casein or other innocuous protein or other moiety.  
      The compounds of the invention may be used on their own to inhibit the activity of a mitotic kinesin, particularly KSP. In one embodiment, a compound of the invention is combined with KSP and the activity of KSP is assayed. Kinesin (including KSP) activity is known in the art and includes one or more kinesin activities. Kinesin activities include the ability to affect ATP hydrolysis; microtubule binding; gliding and polymerization/depolymerization (effects on microtubule dynamics); binding to other proteins of the spindle; binding to proteins involved in cell-cycle control; serving as a substrate to other enzymes, such as kinases or proteases; and specific kinesin cellular activities such as spindle pole separation.  
      Methods of performing motility assays are well known to those of skill in the art. (See e.g., Hall, et al. (1996), Biophys. J., 71: 3467-3476, Turner et al., 1996, AnaL Biochem. 242 (1):20-5; Gittes et al., 1996, Biophys. J. 70(1): 418-29; Shirakawa et al., 1995, J. Exp. BioL 198: 1809-15; Winkelmann et al., 1995, Biophys. J. 68: 2444-53; Winkelmann et al., 1995, Biophys. J. 68: 72S.)  
      Methods known in the art for determining ATPase hydrolysis activity also can be used. Suitably, solution based assays are utilized. U.S. Pat. No. 6,410,254, hereby incorporated by reference in its entirety, describes such assays. Alternatively, conventional methods are used. For example, P i  release from kinesin can be quantified. In one embodiment, the ATPase hydrolysis activity assay utilizes 0.3 M PCA (perchloric acid) and malachite green reagent (8.27 mM sodium molybdate II, 0.33 mM malachite green oxalate, and 0.8 mM Triton X-100). To perform the assay, 10 μL of the reaction mixture is quenched in 90 μL of cold 0.3 M PCA. Phosphate standards are used so data can be converted to mM inorganic phosphate released. When all reactions and standards have been quenched in PCA, 100 μL of malachite green reagent is added to the relevant wells in e.g., a microtiter plate. The mixture is developed for 10-15 minutes and the plate is read at an absorbance of 650 nm. If phosphate standards were used, absorbance readings can be converted to mM P i  and plotted over time. Additionally, ATPase assays known in the art include the luciferase assay.  
      ATPase activity of kinesin motor domains also can be used to monitor the effects of agents and are well known to those skilled in the art. In one embodiment ATPase assays of kinesin are performed in the absence of microtubules. In another embodiment, the ATPase assays are performed in the presence of microtubules. Different types of agents can be detected in the above assays. In a one embodiment, the effect of an agent is independent of the concentration of microtubules and ATP. In another embodiment, the effect of the agents on kinesin ATPase can be decreased by increasing the concentrations of ATP, microtubules or both. In yet another embodiment, the effect of the agent is increased by increasing concentrations of ATP, microtubules or both.  
      Compounds that inhibit the biochemical activity of KSP in vitro may then be screened in vivo. In vivo screening methods include assays of cell cycle distribution, cell viability, or the presence, morphology, activity, distribution, or number of mitotic spindles. Methods for monitoring cell cycle distribution of a cell population, for example, by flow cytometry, are well known to those skilled in the art, as are methods for determining cell viability. See for example, U.S. Pat. No. 6,437,115, hereby incorporated by reference in its entirety. Microscopic methods for monitoring spindle formation and malformation are well known to those of skill in the art (see, e.g., Whitehead and Rattner (1998), J. Cell Sci. 111:2551-61; Galgio et al, (1996) J. Cell Biol., 135:399-414), each incorporated herein by reference in its entirety.  
      The compounds of the invention inhibit the KSP kinesin. One measure of inhibition is IC 50 , defined as the concentration of the compound at which the activity of KSP is decreased by fifty percent relative to a control. Preferred compounds have IC 50 &#39;s of less than about 1 mM, with preferred embodiments having IC 50 &#39;s of less than about 100 μM, with more preferred embodiments having IC 50 &#39;s of less than about 10 μM, with particularly preferred embodiments having IC 50 &#39;s of less than about 1 μM, and especially preferred embodiments having IC 50 &#39;s of less than about 100 nM, and with the most preferred embodiments having IC 50 &#39;s of less than about 10 nM. Measurement of IC 50  is done using an ATPase assay such as described herein.  
      Another measure of inhibition is K i . For compounds with IC 50 &#39;s less than 1 μM, the K i  or K d  is defined as the dissociation rate constant for the interaction of the compounds described herein with KSP. Preferred compounds have K i &#39;s of less than about 100 μM, with preferred embodiments having K i &#39;s of less than about 10 μM, and particularly preferred embodiments having K i &#39;s of less than about 1 μM and especially preferred embodiments having K i &#39;s of less than about 100 nM, and with the most preferred embodiments having K i &#39;s of less than about 10 nM.  
      The K i  for a compound is determined from the IC 50  based on three assumptions and the Michaelis-Menten equation. First, only one compound molecule binds to the enzyme and there is no cooperativity. Second, the concentrations of active enzyme and the compound tested are known (i.e., there are no significant amounts of impurities or inactive forms in the preparations). Third, the enzymatic rate of the enzyme-inhibitor complex is zero. The rate (i.e., compound concentration) data are fitted to the equation:  
       V   =       V   max     ⁢       E   0     ⁢           [     I   -         (       E   0     +     I   0     +   Kd     )     -           (       E   0     +     I   0     +   Kd     )     2     -     4   ⁢           ⁢     E   0     ⁢           ⁢     I   0               2   ⁢           ⁢     E   0           ]           
 
 where V is the observed rate, V max  is the rate of the free enzyme, I 0  is the inhibitor concentration, E 0  is the enzyme concentration, and K d  is the dissociation constant of the enzyme-inhibitor complex. 
 
      Another measure of inhibition is GI 50 , defined as the concentration of the compound that results in a decrease in the rate of cell growth by fifty percent. Preferred compounds have GI 50 &#39;s of less than about 1 mM; those having a GI 50  of less than about 20 μM are more preferred; those having a GI 50  of less than about 10 μM more so; those having a GI 50  of less than about 1 μM more so; those having a GI 50  of less than about 100 nM more so; and those having a GI 50  of less than about 10 nM even more so. Measurement of GI 50  is done using a cell proliferation assay such as described herein. Compounds of this class were found to inhibit cell proliferation.  
      In vitro potency of small molecule inhibitors is determined, for example, by assaying human ovarian cancer cells (SKOV3) for viability following a 72-hour exposure to a 9-point dilution series of compound. Cell viability is determined by measuring the absorbance of formazon, a product formed by the bioreduction of MTS/PMS, a commercially available reagent. Each point on the dose-response curve is calculated as a percent of untreated control cells at 72 hours minus background absorption (complete cell kill).  
      Anti-proliferative compounds that have been successfully applied in the clinic to treatment of cancer (cancer chemotherapeutics) have GI 50 &#39;s that vary greatly. For example, in A549 cells, paclitaxel GI 50  is 4 nM, doxorubicin is 63 nM, 5-fluorouracil is 1 μM, and hydroxyurea is 500 μM (data provided by National Cancer Institute, Developmental Therapeutic Program, http://dtp.nci.nih.gov/). Therefore, compounds that inhibit cellular proliferation, irrespective of the concentration demonstrating inhibition, have potential clinical usefulness.  
      To employ the compounds of the invention in a method of screening for compounds that bind to KSP kinesin, the KSP is bound to a support, and a compound of the invention is added to the assay. Alternatively, the compound of the invention is bound to the support and KSP is added. Classes of compounds among which novel binding agents may be sought include specific antibodies, non-natural binding agents identified in screens of chemical libraries, peptide analogs, etc. Of particular interest are screening assays for candidate agents that have a low toxicity for human cells. A wide variety of assays may be used for this purpose, including labeled in vitro protein-protein binding assays, electrophoretic mobility shift assays, immunoassays for protein binding, functional assays (phosphorylation assays, etc.) and the like.  
      The determination of the binding of the compound of the invention to KSP may be done in a number of ways. In one embodiment, the compound is labeled, for example, with a fluorescent or radioactive moiety, and binding is determined directly. For example, this may be done by attaching all or a portion of KSP to a solid support, adding a labeled test compound (for example a compound of the invention in which at least one atom has been replaced by a detectable isotope), washing off excess reagent, and determining whether the amount of the label is that present on the solid support.  
      By “labeled” herein is meant that the compound is either directly or indirectly labeled with a label which provides a detectable signal, e.g., radioisotope, fluorescent tag, enzyme, antibodies, particles such as magnetic particles, chemiluminescent tag, or specific binding molecules, etc. Specific binding molecules include pairs, such as biotin and streptavidin, digoxin and antidigoxin etc. For the specific binding members, the complementary member would normally be labeled with a molecule which provides for detection, in accordance with known procedures, as outlined above. The label can directly or indirectly provide a detectable signal.  
      In some embodiments, only one of the components is labeled. For example, the kinesin proteins may be labeled at tyrosine positions using  125 I, or with fluorophores. Alternatively, more than one component may be labeled with different labels; using  125 I for the proteins, for example, and a fluorophor for the antimitotic agents.  
      The compounds of the invention may also be used as competitors to screen for additional drug candidates. “Candidate agent” or “drug candidate” or grammatical equivalents as used herein describe any molecule, e.g., protein, oligopeptide, small organic molecule, polysaccharide, polynucleotide, etc., to be tested for bioactivity. They may be capable of directly or indirectly altering the cellular proliferation phenotype or the expression of a cellular proliferation sequence, including both nucleic acid sequences and protein sequences. In other cases, alteration of cellular proliferation protein binding and/or activity is screened. Screens of this sort may be performed either in the presence or absence of microtubules. In the case where protein binding or activity is screened, particular embodiments exclude molecules already known to bind to that particular protein, for example, polymer structures such as microtubules, and energy sources such as ATP. Particular embodiments of assays herein include candidate agents which do not bind the cellular proliferation protein in its endogenous native state termed herein as “exogenous” agents. In another embodiment, exogenous agents further exclude antibodies to KSP.  
      Candidate agents can encompass numerous chemical classes, though typically they are organic molecules, preferably they are small organic compounds having a molecular weight of more than 100 and less than about 2,500 daltons. Candidate agents comprise functional groups necessary for structural interaction with proteins, particularly hydrogen bonding and lipophilic binding, and typically include at least an amine, carbonyl-, hydroxyl-, ether, or carboxyl group, preferably at least two of the functional chemical groups. The candidate agents often comprise cyclical carbon or heterocyclic structures and/or aromatic or polyaromatic structures substituted with one or more of the above functional groups. Candidate agents are also found among biomolecules including peptides, saccharides, fatty acids, steroids, purines, pyrimidines, derivatives, structural analogs or combinations thereof.  
      Candidate agents are obtained from a wide variety of sources including libraries of synthetic or natural compounds. For example, numerous means are available for random and directed synthesis of a wide variety of organic compounds and biomolecules, including expression of randomized oligonucleotides. Alternatively, libraries of natural compounds in the form of bacterial, fungal, plant and animal extracts are available or readily produced. Additionally, natural or synthetically produced libraries and compounds are readily modified through conventional chemical, physical and biochemical means. Known pharmacological agents may be subjected to directed or random chemical modifications, such as acylation, alkylation, esterification, and/or amidification to produce structural analogs.  
      Competitive screening assays may be done by combining KSP and a drug candidate in a first sample. A second sample comprises a compound of the present invention, KSP and a drug candidate. This may be performed in either the presence or absence of microtubules. The binding of the drug candidate is determined for both samples, and a change, or difference in binding between the two samples indicates the presence of a drug candidate capable of binding to KSP and potentially inhibiting its activity. That is, if the binding of the drug candidate is different in the second sample relative to the first sample, the drug candidate is capable of binding to KSP.  
      In a particular embodiment, the binding of the candidate agent to KSP is determined through the use of competitive binding assays. In this embodiment, the competitor is a binding moiety known to bind to KSP, such as an antibody, peptide, binding partner, ligand, etc. Under certain circumstances, there may be competitive binding as between the candidate agent and the binding moiety, with the binding moiety displacing the candidate agent.  
      In one embodiment, the candidate agent is labeled. Either the candidate agent, or the competitor, or both, is added first to KSP for a time sufficient to allow binding, if present. Incubations may be performed at any temperature which facilitates optimal activity, typically between 4 and 40° C.  
      Incubation periods are selected for optimum activity, but may also be optimized to facilitate rapid high throughput screening. Typically between 0.1 and 1 hour will be sufficient. Excess reagent is generally removed or washed away. The second component is then added, and the presence or absence of the labeled component is followed, to indicate binding.  
      In another embodiment, the competitor is added first, followed by the candidate agent. Displacement of the competitor is an indication the candidate agent is binding to KSP and thus is capable of binding to, and potentially inhibiting, the activity of KSP. In this embodiment, either component can be labeled. Thus, for example, if the competitor is labeled, the presence of label in the wash solution indicates displacement by the agent. Alternatively, if the candidate agent is labeled, the presence of the label on the support indicates displacement.  
      In an alternative embodiment, the candidate agent is added first, with incubation and washing, followed by the competitor. The absence of binding by the competitor may indicate the candidate agent is bound to KSP with a higher affinity. Thus, if the candidate agent is labeled, the presence of the label on the support, coupled with a lack of competitor binding, may indicate the candidate agent is capable of binding to KSP.  
      Inhibition is tested by screening for candidate agents capable of inhibiting the activity of KSP comprising the steps of combining a candidate agent with KSP, as above, and determining an alteration in the biological activity of KSP. Thus, in this embodiment, the candidate agent should both bind to KSP (although this may not be necessary), and alter its biological or biochemical activity as defined herein. The methods include both in vitro screening methods and in vivo screening of cells for alterations in cell cycle distribution, cell viability, or for the presence, morpohology, activity, distribution, or amount of mitotic spindles, as are generally outlined above.  
      Alternatively, differential screening may be used to identify drug candidates that bind to the native KSP, but cannot bind to modified KSP.  
      Positive controls and negative controls may be used in the assays. Suitably all control and test samples are performed in at least triplicate to obtain statistically significant results. Incubation of all samples is for a time sufficient for the binding of the agent to the protein. Following incubation, all samples are washed free of non-specifically bound material and the amount of bound, generally labeled agent determined. For example, where a radiolabel is employed, the samples may be counted in a scintillation counter to determine the amount of bound compound.  
      A variety of other reagents may be included in the screening assays. These include reagents like salts, neutral proteins, e.g., albumin, detergents, etc which may be used to facilitate optimal protein-protein binding and/or reduce non-specific or background interactions. Also reagents that otherwise improve the efficiency of the assay, such as protease inhibitors, nuclease inhibitors, anti-microbial agents, etc., may be used. The mixture of components may be added in any order that provides for the requisite binding.  
      Administration  
      Accordingly, the compounds of the invention are administered to cells. By “administered” herein is meant administration of a therapeutically effective dose of a compound of the invention to a cell either in cell culture or in a patient. By “therapeutically effective dose” herein is meant a dose that produces the effects for which it is administered. The exact dose will depend on the purpose of the treatment, and will be ascertainable by one skilled in the art using known techniques. As is known in the art, adjustments for systemic versus localized delivery, age, body weight, general health, sex, diet, time of administration, drug interaction and the severity of the condition may be necessary, and will be ascertainable with routine experimentation by those skilled in the art. By “cells” herein is meant any cell in which mitosis or meiosis can be altered.  
      A “patient” for the purposes of the present invention includes both humans and other animals, particularly mammals, and other organisms. Thus the methods are applicable to both human therapy and veterinary applications. In the preferred embodiment the patient is a mammal, and in the most preferred embodiment the patient is human.  
      Compounds of the invention having the desired pharmacological activity may be administered, preferably as a pharmaceutically acceptable composition comprising an pharmaceutical excipient, to a patient, as described herein. Depending upon the manner of introduction, the compounds may be formulated in a variety of ways as discussed below. The concentration of therapeutically active compound in the formulation may vary from about 0.1-100 wt. %.  
      The agents may be administered alone or in combination with other treatments, i.e., radiation, or other chemotherapeutic agents such as the taxane class of agents that appear to act on microtubule formation or the camptothecin class of topoisomerase I inhibitors. When used, other chemotherapeutic agents may be administered before, concurrently, or after administration of a compound of the present invention. In one aspect of the invention, a compound of the present invention is co-administered with one or more other chemotherapeutic agents. By “co-administer” it is meant that the present compounds are administered to a patient such that the present compounds as well as the co-administered compound may be found in the patient&#39;s bloodstream at the same time, regardless when the compounds are actually administered, including simultaneously.  
      The administration of the compounds and compositions of the present invention can be done in a variety of ways, including, but not limited to, orally, subcutaneously, intravenously, intranasally, transdermally, intraperitoneally, intramuscularly, intrapulmonary, vaginally, rectally, or intraocularly. In some instances, for example, in the treatment of wounds and inflammation, the compound or composition may be directly applied as a solution or spray.  
      Pharmaceutical dosage forms include a compound of formula I or a pharmaceutically acceptable salt, solvate, or solvate of a salt thereof, and one or more pharmaceutical excipients. As is known in the art, pharmaceutical excipients are secondary ingredients which function to enable or enhance the delivery of a drug or medicine in a variety of dosage forms (e.g.: oral forms such as tablets, capsules, and liquids; topical forms such as dermal, opthalmic, and otic forms; suppositories; injectables; respiratory forms and the like). Pharmaceutical excipients include inert or inactive ingredients, synergists or chemicals that substantively contribute to the medicinal effects of the active ingredient. For example, pharmaceutical excipients may function to improve flow characteristics, product uniformity, stability, taste, or appearance, to ease handling and administration of dose, for convenience of use, or to control bioavailability. While pharmaceutical excipients are commonly described as being inert or inactive, it is appreciated in the art that there is a relationship between the properties of the pharmaceutical excipients and the dosage forms containing them.  
      Pharmaceutical excipients suitable for use as carriers or diluents are well known in the art, and may be used in a variety of formulations. See, e.g., Remington&#39;s Pharmaceutical Sciences, 18th Edition, A. R. Gennaro, Editor, Mack Publishing Company (1990); Remington: The Science and Practice of Pharmacy, 20th Edition, A. R. Gennaro, Editor, Lippincott Williams &amp; Wilkins (2000); Handbook of Pharmaceutical Excipients, 3rd Edition, A. H. Kibbe, Editor, American Pharmaceutical Association, and Pharmaceutical Press (2000); and Handbook of Pharmaceutical Additives, compiled by Michael and Irene Ash, Gower (1995), each of which is incorporated herein by reference for all purposes.  
      Oral solid dosage forms such as tablets will typically comprise one or more pharmaceutical excipients, which may for example help impart satisfactory processing and compression characteristics, or provide additional desirable physical characteristics to the tablet. Such pharmaceutical excipients may be selected from diluents, binders, glidants, lubricants, disintegrants, colors, flavors, sweetening agents, polymers, waxes or other solubility-retarding materials.  
      Compositions for intravenous administration will generally comprise intravenous fluids, i.e., sterile solutions of simple chemicals such as sugars, amino acids or electrolytes, which can be easily carried by the circulatory system and assimilated. Such fluids are prepared with water for injection USP.  
      Fluids used commonly for intravenous (IV) use are disclosed in Remington, the Science and Practice of Pharmacy [full citation previously provided], and include:  
      alcohol (e.g., in dextrose and water (“D/W”) [e.g., 5% dextrose] or dextrose and water [e.g., 5% dextrose] in normal saline solution (“NSS”); e.g. 5% alcohol);  
      synthetic amino acid such as Aminosyn, FreAmine, Travasol, e.g., 3.5 or 7; 8.5; 3.5, 5.5 or 8.5% respectively;  
      ammonium chloride e.g., 2.14%;  
      dextran 40, in NSS e.g., 10% or in D5/W e.g., 10%;  
      dextran 70, in NSS e.g., 6% or in D5/W e.g., 6%;  
      dextrose (glucose, D5/W) e.g., 2.5-50%;  
      dextrose and sodium chloride e.g., 5-20% dextrose and 0.22-0.9% NaCl;  
      lactated Ringer&#39;s (Hartmann&#39;s) e.g., NaCl 0.6%, KCl 0.03%, CaCl 2  0.02%;  
      lactate 0.3%;  
      mannitol e.g., 5%, optionally in combination with dextrose e.g., 10% or NaCl e.g., 15 or 20%;  
      multiple electrolyte solutions with varying combinations of electrolytes, dextrose, fructose, invert sugar Ringer&#39;s e.g., NaCl 0.86%, KCl 0.03%, CaCl 2  0.033%;  
      sodium bicarbonate e.g., 5%;  
      sodium chloride e.g., 0.45, 0.9, 3, or 5%;  
      sodium lactate e.g., ⅙ M; and  
      sterile water for injection  
      The pH of such fluids may vary, and will typically be from 3.5 to 8 such as known in the art.  
      The following examples serve to more fully describe the manner of using the above-described invention, as well as to set forth the best modes contemplated for carrying out various aspects of the invention. It is understood that these examples in no way serve to limit the true scope of this invention, but rather are presented for illustrative purposes. All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.  
     EXAMPLES  
      All anhydrous solvents were purchased from Aldrich Chemical Company in SureSeal® containers.  
     Example 1  
     
       
         
         
             
             
         
       
       
         
         
             
             
         
       
     
      Lithium bis(trimethylsilyl)amide (LHMDS, 1.0 M in THF, 5.7 mL, 2.2 equiv) was added slowly via syringe to a −78° C. solution of ketone 1 (0.79 g, 2.6 mmol) and THF (10 mL). The reaction solution temperature was monitored by an internal thermometer, and addition of the base was done at a rate sufficient to prevent the temperature from exceeding −48° C. After the addition was complete the resulting solution was maintained at −78° C. for 30 mins. A solution of aldehyde 2 1  (350 mg, 3.27 mmol) and THF (2 mL) was added dropwise via syringe. The reaction solution was stirred for 30 mins. The reaction solution was quenched with saturated aqueous NH 4 Cl (5 mL). The layers were separated and the organic layer was washed with brine (5 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated. The resulting residue was used without further purification.  1 Synth. Commun., 22(5), 767-72; 1992.    
      A solution of above crude 3 (˜2.59 mmol), Dess-Martin periodinane 2  (1.10 g, 2.59 mmol), and CH 2 Cl 2  (15 mL) were maintained at 23° C. for 45 mins. The reaction mixture was quenched by addition of EtOAc (50 mL) and NaHCO 3  (20 mL). The layers were separated and the organic layer was washed with brine (10 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated. The resulting residue was used without further purification.  2 Dess, D. B.; Martin, J. C.  J. Org. Chem.  1993, 48, 4156.    
      A mixture of the above crude ketone 4 (˜2.59 mmol), K 2 CO 3  (800 mg, 6.0 mmol) and DMF (5 mL) was maintained at 75° C. for 20 mins. The reaction mixture was quenched by addition of EtOAc (50 mL) and brine (30 mL). The layers were separated and the organic layer was washed with brine (2×30 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated. The resulting residue was purified by flash column chromatography (1:1 hexanes:EtOAc) to yield 170 mg (18% from 1) of 5. LRMS (MH) m/z 372.2.  
      Pyranone 5 (210 mg, 0.56 mmol) and TFA:H 2 O (97.5:2.5, 5 mL) was maintained at 23° C. for 1 h. The reaction mixture was concentrated. The residue was dissolved in EtOAc (100 mL) and washed with 1 N NaOH (25 mL) and brine (25 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated to provide a colorless oil, which was used without further purification.  
      Crude pyranone 6 (˜0.56 mmol), aldehyde 7 (117 mg, 0.68 mmol), NaCN(OAc) 3 BH (240 mg, 1.13 mmol), and CH 2 Cl 2  (2 mL) was maintained at 23° C. for 18 h. The reaction mixture was diluted with EtOAc (20 mL) and washed with 1 N NaOH (5 mL) and brine (5 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated. The resulting residue was purified by flash column chromatography (100% EtOAc) to yield 179 mg (74%) of 8 as a viscous oil.  
      To a solution of pyranone 8 (179 mg, 0.42 mmol), diisoproylethylamine (DIEA, 0.3 mL), and CH 2 Cl 2  (2 mL) at 23° C. was added p-toluoyl chloride (0.066 mL, 0.50 mmol). After 6 h, the reaction mixture was diluted with EtOAc (20 mL) and washed with saturated aqueous NaHCO 3  (2×5 mL) and brine (5 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated. The resulting residue was purified by flash column chromatography (3:1 hexanes:EtOAc; 1:1 hexanes:EtOAc) to yield 100 mg (44%) of 9 as a colorless oil.  
      Pyanone 9 (100 mg, 0.18 mmol) and TFA:H 2 O (97.5:2.5, 3 mL) was maintained at 23° C. for 1 h. The reaction mixture was concentrated. The residue was dissolved in EtOAc (20 mL) and washed with 1 N NaOH (5 mL) and brine (5 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated to provide a white solid (10) which was deemed &gt;95% pure by  1 H NMR and LCMS analysis.  
     Example 2  
     ((R)-1-Isopropyl-2-oxo-but-3-enyl)-carbamic Acid Tert-butyl Ester  
     
       
         
         
             
             
         
       
     
      Tetrahydrofuran (THF, 100 mL) and a 1.0M solution of vinyl magnesium bromide in THF (360 mL, 360 mmol, 3.1 equiv) was cooled to −78° C. while stirring under a nitrogen atmosphere. The mixture was treated dropwise with a solution of [(R)-(methoxy-methyl-carbamoyl)-methyl-propyl]-carbamic acid tert-butyl ester (30.3 g, 116 mmol, 1 equiv) in THF (50 mL) over 30 min. After the resultant dark yellow mixture was stirred for 30 min at −78° C., the cooling bath was removed and the reaction mixture was warmed slowly to room temperature overnight (15 h). The reaction mixture was poured slowly into an ice-chilled solution of 1N aqueous hydrochloric acid (700 mL) and then warmed to room temperature. The organics were extracted with (3×600 mL) ethyl acetate, dried over sodium sulfate, filtered, and concentrated in vacuo. Purification by flash column chromatography (5-10% ethyl acetate/hexanes) provided the product as a white solid (16.8 g, 64%). ESMS [M+H] + : 228.4.  
     Example 3  
     
       
         
         
             
             
         
       
     
     [(R)-(E)-1-Isopropyl-4-(3-methoxy-phenyl)-2-oxo-but-3-enyl]-carbamic Acid Tert-butyl Ester  
      To a solution of ((R)-1-Isopropyl-2-oxo-but-3-enyl)-carbamic acid tert-butyl ester (13.54 g, 59.6 mmol) in dry acetonitrile (150 mL) under argon, was added 3-iodoanisole (13.96 g, 59.6 mmol), triethylamine (9.1 mL, 65.6 mmol) followed by palladium (II) acetate (335 mg, 1.49 mmol). The resulting clear yellow solution was heated to 80 □C. Upon heating, the reaction darkened and the precipitation of palladium black occurred. After 15 h, the reaction mixture was allowed to cool to room temperature, quenched with water (150 mL) and diluted with ether (150 mL). The ether layer was washed with brine (100 mL) and the combined aqueous layers were extracted with ether (two 50 mL portions). The extracts were dried over magnesium sulfate, filtered and, concentrated under reduced pressure. The residue was immediately purified by silica gel chromatography (9:1 hexanes/EtOAc) to provide 17.6 g (88%) of [(R)-(E)-1-Isopropyl-4-(3-methoxy-phenyl)-2-oxo-but-3-enyl]-carbamic acid tert-butyl ester as a yellow oil. MS(ES+) m/e 334.0 [M+H] + .  
     Example 4  
     [(R)-(Z)-4-(3-Cyano-phenyl)-1-isopropyl-2-oxo-but-3-enyl]-carbamic Acid Tert-butyl Ester  
      Following the procedure described for [(R)-(E)-1-isopropyl-4-(3-methoxy-phenyl)-2-oxo-but-3-enyl]-carbamic acid tert-butyl ester with 3-iodobenzonitrile (5.50 g, 24.0 mmol, 1 equiv) afforded the title compound as a yellow solid (7.4 g of ˜90% purity material). ESMS [M+H] + : 329.2.  
     Example 5  
     
       
         
         
             
             
         
       
     
     [(R)-(E)-1-Isopropyl-4-(3-methoxy-phenyl)-2-oxo-butyl]-carbamic Acid Tert-butyl Ester  
      To a solution of [(R)-(E)-1-Isopropyl-4-(3-methoxy-phenyl)-2-oxo-but-3-enyl]-carbamic acid tert-butyl ester (17.6 g, 52.9 mmol) in ethyl acetate (450 mL) under nitrogen was added 10 wt % palladium on carbon (300 mg). The nitrogen was replaced with a balloon of hydrogen and the flask was purged. After 3 h, the reaction flask was purged with nitrogen and filtered through a pad of celite (rinsing with ethyl acetate). The filtrate was concentrated under reduced pressure and the residue was purified by silica gel chromatography (9:1 hexanes/EtOAc) to provide 16.2 g (91%) of [(R)-(E)-1-Isopropyl-4-(3-methoxy-phenyl)-2-oxo-butyl]-carbamic acid tert-butyl ester as a colorless oil. MS(ES+) m/e 336.4 [M+H] + . [□] D   20 =+19.1 (c=0.755, MeOH).  1 H NMR (400 MHz, CDCl 3 ) □ 7.21 (m, 1H), 6.80-6.77 (m, 2H), 6.75 (s, 1H), 5.13 (d, J=8.4 Hz, 1H), 4.28 (dd, J=8.8, 4.4 Hz, 1H), 3.81 (s, 3H), 2.93-2.88 (m, 2H), 2.85-2.76 (m, 2H), 2.14 (m, 1H), 1.46 (s, 9H), 1.00 (d, J=6.8 Hz, 3H), 0.75 (d, J=6.8 Hz, 3H).  
     Example 6  
     
       
         
         
             
             
         
       
     
     [(R)-4-(3-Cyano-phenyl)-1-isopropyl-2-oxo-butyl]-carbamic Acid Tert-butyl Ester  
      Palladium on carbon (740 mg of 10% wt/wt Pd/C) was added to a degassed solution of [(R)-(Z)-4-(3-cyano-phenyl)-1-isopropyl-2-oxo-but-3-enyl]-carbamic acid tert-butyl ester (7.4 g, 22.5 mmol, 1 equiv) in methanol (200 mL) at room temperature. The reaction mixture was thoroughly degassed and backfilled with hydrogen gas from a balloon. Hydrogenation proceeded at atmospheric pressure for 2.5 h. The (degassed) reaction mixture was then diluted with diethyl ether (300 mL), filtered through Celite, and washed with additional ether (2×100 mL). Upon concentration in vacuo, the residue was purified by flash column chromatography (20% ethyl acetate-hexanes) to provide the ketone product as a white solid (5.9 g, 79%). ESMS [M+H] + : 331.2.  1 H NMR (400 MHz, CDCl 3 ) □ 7.51 (m, 2H), 7.46 (m, 1H), 7.41 (m, 1H), 5.07 (m, 1H), 4.24 (m, 1H), 2.98 (m, 2H), 2.86 (m, 2H), 2.11 (m, 1H), 1.45 (s, 9H), 0.98 (d, 3H, J=6.76 Hz), 0.74 (d, 3H, J=6.78 Hz). [□] D =+24.74 (c=0.95, CH 3 OH).  
     Example 7  
     
       
         
         
             
             
         
       
     
      Ethylchloroformate (11.0 mL, 115 mmol) was added over 1 minute to a 0-5 C solution of BOC-D-Valine (1, 25.0 g, 115 mmol), triethylamine (16.0 mL, 115 mmol), and THF (145 mL) under N 2 . The internal temperature of the reaction solution rose to 9 C. After 15 mins, a mixture of dimethylhydroxylamine hydrochloride (13.46 g, 138 mmol), triethylamine (32.0 mL, 230 mmol), and THF (110 mL) was added over 5 minutes. The internal temperature rose to 17 C. Upon completion of addition, the ice/H 2 O bath was removed and the reaction solution maintained at 23 C for 1 hour. The reaction solution was then concentrated. The crude residue was dissolved in EtOAc (200 mL) and washed with 1 N HCl (200 mL) and brine (100 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated to provide 30 g (˜100%) of 2 as a colorless oil, which was used without further purification.  
      (2-Bromoethyl)benzene (38.0 mL, 273 mmol), magnesium turnings (7.0 g, 289 mmol), and Et 2 O (500 mL) were mixed in a 1 L round-bottom flask equipped with a reflux condenser at 23 C under a N 2  atmosphere. After ˜10 mins the reaction mixture begins to exotherm and the reaction mixture was allowed to progress to reflux with intermittent cooling with an ice/H 2 O bath. After 1.5 hour, the Grignard reaction was complete and the solution had cooled to 23 C. A solution of 2 (18.0 g, 82.7 mmol) and Et 2 O (200 mL) was added via cannula to the 20 C solution of the phenethyl magnesiumbromide. The temperature was monitored by internal thermometer and was not allowed to exceed ˜30 C. The reaction mixture temperature was monitored by an internal thermometer and regulated (20-30 C) with an ice/H 2 O bath. After 1 h at 23 C, the reaction mixture was quenched by pouring into 1 N HCl (300 mL). The layers were separated and the organic layer was washed with brine (100 mL). The organic layer was dried (MgSO 4 ), filtered, and concentrated. The resulting residue was purified by flash column chromatography (10:1 hexanes:EtOAc) to yield 13.4 g (53%) of 3. LRMS (MH-tBuOCO) m/z 206.1.  
     Example 8  
     Inhibition of Cellular Viability in Tumor Cell Lines Treated with KSP Inhibitors Materials and Solutions  
      Cells: SKOV3, Ovarian Cancer (human).  
      Media: Phenol Red Free RPMI+5% Fetal Bovine Serum+2 mM L-glutamine.  
      Colorimetric Agent for Determining Cell Viability: Promega MTS tetrazolium compound.  
      Control Compound for max cell kill: Topotecan, 1 μM.  
      Procedure: Day 1—Cell Plating:  
      Adherent SKOV3 cells are washed with 10 mLs of PBS followed by the addition of 2 mLs of 0.25% trypsin and incubation for 5 minutes at 37° C. The cells are rinsed from the flask using 8 mL of media (phenol red-free RPMI+5%FBS) and transferred to fresh flask. Cell concentration is determined using a Coulter counter and the appropriate volume of cells to achieve 1000 cells/100 μL is calculated. 100 μL of media cell suspension (adjusted to 1000 cells/100 μL) is added to all wells of 96-well plates, followed by incubation for 18 to 24 hours at 37° C., 100% humidity, and 5% CO 2 , allowing the cells to adhere to the plates.  
      Procedure: Day 2—Compound Addition:  
      To one column of the wells of an autoclaved assay block are added an initial 2.5 μL of test compound(s) at 400X the highest desired concentration. 1.25 μL of 400X (400 μM) Topotecan is added to other wells (optical density&#39;s from these wells are used to subtract out for background absorbance of dead cells and vehicle). 500 μL of media without DMSO are added to the wells containing test compound, and 250 μL to the Topotecan wells. 250 μL of media+0.5% DMSO is added to all remaining wells, into which the test compound(s) are serially diluted. By row, compound-containing media is replica plated (in duplicate) from the assay block to the corresponding cell plates. The cell plates are incubated for 72 hours at 37° C., 100% humidity, and 5% CO 2 .  
      Procedure: Day 4—MTS Addition and OD Reading:  
      The plates are removed from the incubator and 40 μL MTS/PMS is added to each well. Plates are then incubated for 120 minutes at 37° C., 100% humidity, 5%CO 2 , followed by reading the ODs at 490 nm after a 5 second shaking cycle in a ninety-six well spectrophotometer.  
      Data Analysis  
      The normalized % of control (absorbance-background) is calculated and an XLfit is used to generate a dose-response curve from which the concentration of compound required to inhibit viability by 50% is determined. The compounds of the present invention show activity when tested by this method as described above.  
     Example 9  
     Enantiomer Separation  
      In general, the procedures described above can be used to prepare substantially pure or enriched R- or S-enantiomers by selected a starting amino acid of the appropriate R- or S-configuration. More preferred compounds of the invention are those of the R-configuration at the stereogenic center to which R 2  is attached. An R:S mixture can be separated into its constituent pure enantiomers by methods well known to those skilled in the art. These include the formation and separation of diastereomeric derivatives such as those formed by reaction with an optically pure acid such as dibenzoyltartaric acid. Alternatively, separateion can be accomplished by chiral chromatography, for example, using the following conditions:  
      Column: Chiralcel OD 20×250 mm;  
      Sample loaded ˜100 mg mL −1  in 1:2 ethanol:hexane containing 0.01% isopropylaamine;  
      Chromatography conditions: isocratic elution with 1:2 ethanol:hexane containing 0.01% isopropylamine at a flow rate of 15 mL min −1 ;  
      UV detection at 254 nm.  
      For example, an enriched 3:1 R:S mixture of enantiomers is separated into its pure enantiomers by chiral chromatography with the following conditions: Chiralpak AD, 250×4.6 mm (Diacel Inc.). Sample—22.5 mg/ml in 1:1 i-PrOH:hexanes. Conditions—40 min at isocratic 50% i-PrOH in Hexanes, (S)-enantiomer elutes at 18.35 min, (R)-enantiomer elutes at 26.87 min. The (R)-enantiomer is significantly more potent than the (S)-enantiomer.  
     Example 10  
     Monopolar Spindle Formation following Application of a KSP Inhibitor  
      Human tumor cells Skov-3 (ovarian) are plated in 96-well plates at densities of 4,000 cells per well, allowed to adhere for 24 hours, and treated with various concentrations of the pyridmidinone derivatives for 24 hours. Cells are fixed in 4% formaldehyde and stained with antitubulin antibodies (subsequently recognized using fluorescently-labeled secondary antibody) and Hoechst dye (which stains DNA).  
      Visual inspection reveals that the compounds caused cell cycle arrest in the prometaphase stage of mitosis. DNA is condensed and spindle formation is initiated, but arrested cells uniformly display monopolar spindles, indicating that there is an inhibition of spindle pole body separation. Microinjection of anti-KSP antibodies also causes mitotic arrest with arrested cells displaying monopolar spindles.  
     Example 11  
     Inhibition of Cellular Proliferation in Tumor Cell Lines Treated with KSP Inhibitors  
      Cells are plated in 96-well plates at densities from 1000-2500 cells/well of a 96-well plate and allowed to adhere/grow for 24 hours. They are then treated with various concentrations of drug for 48 hours. The time at which compounds are added is considered T 0 . A tetrazolium-based assay using the reagent 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) (U.S. Pat. No. 5,185,450) (see Promega product catalog #G3580, CellTiter 96® AQ ueous  One Solution Cell Proliferation Assay) is used to determine the number of viable cells at T 0  and the number of cells remaining after 48 hours compound exposure. The number of cells remaining after 48 hours is compared to the number of viable cells at the time of drug addition, allowing for calculation of growth inhibition.  
      The growth over 48 hours of cells in control wells that had been treated with vehicle only (0.25% DMSO) is considered 100% growth and the growth of cells in wells with compounds is compared to this.  
      A Gi 50  is calculated by plotting the concentration of compound in μM vs the percentage of cell growth in treated wells. The Gi 50  calculated for the compounds is the estimated concentration at which growth is inhibited by 50% compared to control, i.e., the concentration at which:
 
100×[(Treated 48   −T   0 )/(Control 48   −T   0 )]=50
 
 wherein Treated 48  is the value at 48 hours for the treated cells and Control 48  is the value at 48 hours for the control population. 
 
      All concentrations of compounds are tested in duplicate and controls are averaged over 12 wells. A very similar 96-well plate layout and Gi 50  calculation scheme is used by the National Cancer Institute (see Monks, et al., J. Natl. Cancer Inst. 83:757-766 (1991)). However, the method by which the National Cancer Institute quantitates cell number does not use MTS, but instead employs alternative methods.  
      The compound of Example 1 above inhibited cell proliferation in human ovarian tumor cell lines (SKOV-3).  
     Example 12  
     Calculation of IC 50    
      Measurement of a compound&#39;s IC 50  for KSP activity uses an ATPase assay. The following solutions are used: Solution 1 consists of 3 mM phosphoenolpyruvate potassium salt (Sigma P-7127), 2 mM ATP (Sigma A-3377), 1 mM IDTT (Sigma D-9779), 5 μM paclitaxel (Sigma T-7402), 10 ppm antifoam 289 (Sigma A-8436), 25 mM Pipes/KOH pH 6.8 (Sigma P6757), 2 mM MgC12 (VWR JT400301), and 1 mM EGTA (Sigma E3889). Solution 2 consists of 1 mM NADH (Sigma N8129), 0.2 mg/ml BSA (Sigma A7906), pyruvate kinase 7 U/ml, L-lactate dehydrogenase 10 U/ml (Sigma P0294), 100 nM KSP motor domain, 50 μg/ml microtubules, 1 mM DTT (Sigma D9779), 5 μM paclitaxel (Sigma T-7402), 10 ppm antifoam 289 (Sigma A-8436), 25 mM Pipes/KOH pH 6.8 (Sigma P6757), 2 mM MgC12 (VWR JT4003-01), and 1 mM EGTA (Sigma E3889). Serial dilutions (8-12 two-fold dilutions) of the compound are made in a 96-well microtiter plate (Corning Costar 3695) using Solution 1. Following serial dilution each well has 50 μl of Solution 1. The reaction is started by adding 50 μl of solution 2 to each well. This may be done with a multichannel pipettor either manually or with automated liquid handling devices. The microtiter plate is then transferred to a microplate absorbance reader and multiple absorbance readings at 340 nm are taken for each well in a kinetic mode. The observed rate of change, which is proportional to the ATPase rate, is then plotted as a function of the compound concentration. For a standard IC 50  determination the data acquired is fit by the following four parameter equation using a nonlinear fitting program (e.g., Grafit 4):  
       y   =       Range     1   +       (     x     IC   50       )     s         +   Background         
 
 where y is the observed rate and x is the compound concentration.