Patent Publication Number: US-2007098676-A1

Title: Functionally diverse macromolecules and their synthesis

Description:
CROSS REFERENCE TO RELATED APPLICATION  
      This application is a continuation-in-part of U.S. application Ser. No. 11/419,200 filed May 18, 2006, which claims priority to U.S. Provisional Application No. 60/706,884 filed Aug. 10, 2005, both of which are incorporated herein in their entirety. 
    
    
      The government has rights in the present invention pursuant to NIH grant (NIGMS 65460). 
    
    
     BACKGROUND OF THE INVENTION  
      A. Field of the Invention  
      The present invention relates generally to synthetic routes for obtaining functional group diversity in macromolecules and to functionally diverse macromolecules. This diversity permits the facile introduction of a variety of diversity groups at multiple positions of these macromolecules, thereby setting the stage for further generational growth of the macromolecule and/or incorporation of other groups such as biocompatible targeting groups.  
      B. Background of the Invention  
      Even when reduced to trivial manipulations, the synthesis of macromolecules such as dendrimers remains laborious (Grayson et al., 2001; Newkome et al., 2001; Frèchet and Tomalia, 2002) with few exceptions-notably, one-pot syntheses (Okaniwa et al., 2002; Rannard, 2000). As applications are pursued for these macromolecular architectures, the need to execute structure-property relationships only further increases the burden of synthesis. Not surprisingly, the number of reports of libraries of macromolecules such as dendrimers are exceedingly few, and in many cases these libraries are the result of substoichiometric (with respect to the number of reactive surface groups) and statistical reactions of the periphery to yield cocktails of molecules as opposed to single-molecule chemical entities (Singh, 1998; Newkome et al., 1998; Newkome et al., 1999; Baker et al., 2001).  
     SUMMARY OF THE INVENTION  
      The inventors have identified means of providing facile divergent synthetic methods for the preparation of functionally diverse macromolecules as single-molecule chemical entities. In certain non-limiting aspects, the macromolecules display a variety of diversity groups at multiple positions, thereby setting the stage for further generational growth of the macromolecule and/or incorporation of other diversity groups such as biocompatible targeting groups.  
      One embodiment of the invention is a method of synthesizing a macromolecule, comprising: (a) obtaining a nucleophile-bearing core including at least one nucleophilic group, and (b) reacting the core with a first monomeric electrophilic triazine including at least one substitutable group and at least one of either a protected-nucleophilic group or an unreactive group, wherein the macromolecule has one less substitutable group when compared to the first monomeric electrophilic triazine and at least one of either a protected-nucleophilic group or unreactive group. In a further embodiment, the first monomeric electrophilic triazine includes at least 2 substitutable groups, such that the macromolecule includes at least one substitutable group. In another embodiment the method further comprises reacting the macromolecule with at least one substitutable group with a first diversity group, such that at least one substitutable group is substituted with the first diversity group. In yet another embodiment, the method further comprises removing at least one protecting group of the macromolecule.  
      In another embodiment of the invention, the method further comprises reacting the macromolecule with a second electrophilic monomeric triazine including at least one substitutable group and at least one of either a protected-nucleophilic group or an unreactive group, wherein the macromolecule has one less substitutable group when compared to the second monomeric electrophilic triazine and at least one of either a protected-nucleophilic group or unreactive group. In a further embodiment, the method further comprises removing one or more protecting groups. In still another embodiment, the method further comprises subjecting the macromolecule to iterative steps of the methods described above, wherein the macromolecule becomes the nucleophile-bearing core of step (a). In yet another embodiment, the method further comprises subjecting the macromolecule to iterative steps of the methods described above, wherein the macromolecule becomes the nucleophile-bearing core of step (a). In another embodiment, the first monomeric electrophilic triazine includes at least one unreactive group.  
      In a further embodiment of the invention, the first monomeric electrophilic triazine further comprises at least one diversity group and two substitutable groups. In still another embodiment, the method further comprises reacting the macromolecule with a nucleophile-bearing group, wherein the macromolecule has one less substitutable group when compared to the first monomeric electrophilic triazaine. In yet another embodiment, the method further comprises removing one or more protecting groups from the macromolecule, while in another embodiment the first monomeric electrophilic triazine includes at least one nucleophile-bearing group and at least two substitutable groups. In another embodiment, the method further comprises reacting the macromolecule with a diversity group, wherein the macromolecule has one less substitutable group when compared to the first monomeric electrophilic triazaine. In yet another embodiment, the method further comprises removing one or more protecting groups from the macromolecule, while in another embodiment the method further comprises subjecting the macromolecule to iterative steps of other embodiments of the method.  
      In another embodiment, the method further comprises subjecting the macromolecule to iterative steps of other embodiments of the method, wherein the macromolecule becomes the nucleophile-bearing core of those embodiments. In some embodiments, the method further comprises subjecting the macromolecule to iterative steps of other embodiments of the method, wherein the macromolecule becomes the nucleophile-bearing group of those embodiments. In still other embodiments, the method further comprises subjecting the macromolecule to iterative steps of other embodiments, wherein the macromolecule becomes the nucleophile-bearing core of those embodiments.  
      In a further embodiment, the first monomeric electrophilic triazine includes at least 2 or at least 4 nucleophilic groups. In another embodiment, the nucleophile-bearing core including at least one nucleophilic group comprises:  
                 
 
 wherein A1 is a first nucleophile-bearing group and, A2 and A3 are selected from a group consisting of a second nucleophile-bearing group and a third nucleophilic group, and an unreactive group. In yet another embodiment, any one or more of A1-A3 is an amine-bearing group. In still another embodiment, the amine-bearing group is selected from a group consisting of an —NH2-bearing group and an —R—NH2-bearing group, wherein R is selected from the group consisting of a hydrocarbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, and any combination of one or more of these groups. In another embodiment, the amine-bearing group is a secondary amine-bearing group. In still another embodiment, the secondary amine-bearing group is a cycloalkylamino-bearing group. 
 
      In another embodiment, the cycloalkylamino-bearing group is selected from the group consisting of a piperazino-  
                 
 
 -bearing group and a (R1-aminoalkyl)cycloamino-bearing group, wherein R1 equals H, R-amino, acyl, or triazinyl and wherein R1 is selected from the group consisting of a hydrocarbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, and any combination of one or more of these groups. In yet another embodiment, any one or more of A1-A3 is selected from a group consisting of a sulfur group in a reactive state or an oxygen group in a reactive state. In still another embodiment, the nucleophile-bearing group of A1 and A2 are the same. In a further embodiment, each of the nucleophile-bearing groups of A1 and A2 is different. In still a further embodiment, A1, A2, and A3 are all nucleophile-bearing groups that are the same, while in another embodiment, A1, A2, and A3 are all nucleophile-bearing groups that are different. 
 
      In a further embodiment, the unreactive group is selected from the group consisting of a hydrocarbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, and any combination of one or more of these groups. In another embodiment, one or more of the monomeric electrophilic triazines comprises:  
                 
 
      wherein: C1-C8 is each independently a substitutable group, L1-L13 is each independently a linker group, R2-R12 is each independently a protected nucleophilic group, and a-m is each independently 0-200. In yet another embodiment, any one or more of C1-C8 is a halogen. In still another embodiment, the halogen is chlorine. In a further embodiment, any one or more of L1-L13 is selected from the group consisting of a hydrocarbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, and any combination of one or more of these groups.  
      In another embodiment, the secondary or tertiary amine-containing group is piperazino-  
                 
 
 wherein R1 equals H, R-amino, acyl, or triazinyl, and wherein R1 is selected from the group consisting of a hydrocarbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, and any combination of one or more of these groups. In yet another embodiment, one or more oxo-containing groups is an ether, while in another embodiment the ether is polyethylene glycol. In still another embodiment, any one or more of L1-L13 comprises one or more amido-containing groups, while in another embodiment the one or more amido-containing groups is a protected carbohydrate or a protected peptide. In another embodiment, any one or more of L1-L13 comprises a hydrocarbon group, while in a further embodiment the one or more alkyl groups comprises (—CH2-)a-m. In yet another embodiment, a-g of any one or more of (—CH2-)a-m groups is 2 or 3 (i.e., ethyl or propyl). In still another embodiment, any one or more of R2-R12 is selected from the group consisting of a protected amino group, a protected hydroxyl group, a protected carbonyl group, a protected carboxyl group, a protected thiol group, and a protected phosphate group. In a further embodiment, any one or more of R2-R12 comprises a protected amino group, while in another embodiment the protected amino group is selected from a group consisting of a Boc-protected amino group or an acetyl protected amino group. 
 
      In a further embodiment, any one or more L1-L13)a-m-R2-12) comprises one or more ethylamino groups wherein one or more of the amino groups is protected by a protecting group. In another embodiment, the one or more protecting groups is selected from a group consisting of a Boc group or an acetyl group. In still another embodiment, the protected amino group provides a protecting group that can be readily converted to a nucleophilic amine in one or more steps. In another embodiment, the protecting group that can be readily converted to a nucleophilic amine in one or more steps is selected from a group consisting of a carbamate, an amide, and an imide, while in another embodiment, the carbamate is BOC. In yet another embodiment, the amide is acetyl, while in another embodiment the imide is phthalamidoyl. In another embodiment, any one or more of R2-R12 comprises a protected hydroxyl group. In a further embodiment, a-m is each independently 0-10, while in a further embodiment a-m is each independently 0-2.  
      Another embodiment of the invention is a method wherein the diversity group is selected from the group consisting of H, a hydrogen-containing group, a carbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, a phosphino-containing group, a metal-containing group, a nucleophile-bearing group, a protected nucleophile-bearing group, an electrophile-bearing group, a compatibilizing group, a polymer, a resin, a bead, a targeting group, a drug, a solubility enhancer, and any combination of one or more of these groups. In another embodiment, the diversity group is a carbon-containing group attached to the macromolecule, while in yet another embodiment the carbon-containing group is an electrophile-bearing group. In still another embodiment, the carbon-containing group is a nucleophile-bearing group. In yet another embodiment, the diversity group is attached to the macromolecule through an attachment consisting of the group selected from carbon-carbon single bond, an alkene, an amide, a sulfonamide, an ester, an ether, a thioether, a carbonyl, and a thiocarbonyl. In a further embodiment, the diversity group is —(CH2)2-O—(CH2)n-OH or —(CH2)2-O—(CH2)n-OCH3.  
      In a further embodiment, the diversity group is selected from a group consisting of a protein, a peptide, a carbohydrate, an enzyme, an antibody, an antibacterial agent, an antibiotic, an antiviral agent, an antifungal agent, an anticancer agent, a tumor marker, a cell targeting ligand, a DNA intercalator, an organ-specific ligand, and a compatibilizing group. In yet another embodiment, the compatibilizing group is selected from the group consisting of an anionic group, a cationic group, or a polyalkylene glycol. In still another embodiment, the polyalkylene glycol is polyethylene glycol. In a further embodiment, the diversity group is a targeting group, while in another embodiment the targeting group is a therapeutic agent. In yet another embodiment, the diversity group is attached to the macromolecule via a linker.  
      In another embodiment, the linker is selected from the group consisting of a hydrocarbon-containing group, a secondary or tertiary amine-containing group, an oxo-containing group, a thiol-containing group, an amido-containing group, a phosphino-containing group, and any combination of one or more of these groups. In yet another embodiment, the linker is selected from the group consisting of  
                 
 
      Another embodiment of the invention is a macromolecule synthesized by any one of the methods encompassed by the embodiments described above. In a further embodiment, the macromolecule is selected from the group consisting of:  
                 
                 
                 
                 
 
      A further embodiment of the invention is a monomeric electrophilic triazine of the formula:  
                 
 
 wherein: C1-C8 is each independently a substitutable group, L1-L13 is each independently a linker group, R2-R12 is each independently a protected nucleophilic group, and a-m is each independently 0-200. 
 
      Another embodiment of the invention is a compound of the formula: H-J-K, wherein: H comprises a nucleophile-bearing core having one or more nucleophilic groups of the formula:  
                 
 
 wherein: A1 is a first nucleophile-bearing group, and A2, and A3 are selected from a group consisting of a second nucleophile-bearing group, which may or may not be the same as the first nucleophilic group, a third nucleophilic group, which may or may not be the same as the first and second nucleophilic groups, and an unreactive group; provided that H is bound to J through a nucleophilic reaction wherein one of H&#39;s nucleophilic groups has reacted with one of J&#39;s electrophilic groups; J comprises a monomeric electrophilic triazine of the formula:  
                 
 
 wherein: C1-C8 is each independently a substitutable group, L1-L13 is each independently a linker group, R2-R12 is each independently a protected nucleophilic group, and a-m is each independently 0-200; provided that J is bound to H in the manner described above and one bond of J is bound to K via a covalent bond; and K comprises a diversity group. 
 
      One embodiment of the invention is a method of treating, diagnosing, or imaging a subject, comprising administering to the subject a pharmaceutically effective amount of a macromolecule prepared by the method of certain embodiments described above. In one embodiment, the subject is selected from the group consisting of a receptor, cell, tissue, organ, or mammal.  
      Another embodiment of the invention is a method of treating, diagnosing, or imaging a subject, comprising administering to the subject a pharmaceutically effective amount of a macromolecule of the present invention. In one embodiment, the subject is selected from the group consisting of a receptor, cell, tissue, organ, or mammal.  
      Another embodiment of the invention is a method of treating, diagnosing, or imaging a subject, comprising administering to the subject a pharmaceutically effective amount of a macromolecule of the present invention. In one embodiment, the subject is selected from the group consisting of a receptor, cell, tissue, organ, or mammal  
      Macromolecules of the invention may contain one or more asymmetric centers and thus can occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diasteromers. All possible stereoisomers of the macromolecules of the present invention are contemplated as being within the scope of the present invention. The chiral centers of the macromolecules of the present invention can have the S- or the R-configuration, as defined by the IUPAC 1974 Recommendations. The present invention is meant to comprehend all such isomeric forms of the compounds of the invention.  
      The claimed invention is also intended to encompass salts of any of the synthesized macromolecules of the present invention. The term “salt(s)” as used herein, is understood as being acidic and/or basic salts formed with inorganic and/or organic acids and bases. Zwitterions (internal or inner salts) are understood as being included within the term “salt(s)” as used herein, as are quaternary ammonium salts such as alkylammonium salts. Nontoxic, pharmaceutically acceptable salts are preferred as described below, although other salts may be useful, as for example in isolation or purification steps.  
      Examples of acid addition salts include but are not limited to acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, pectinate, persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, tosylate, and undecanoate.  
      Examples of basic salts include but are not limited to ammonium salts; alkali metal salts such as sodium, lithium, and potassium salts; alkaline earth metal salts such as calcium and magnesium salts; salts comprising organic bases such as amines (e.g., dicyclohexylamine, alkylamines such as t-butylamine and t-amylamine, substituted alkylamines, aryl-alkylamines such as benzylamine, dialkylamines, substituted dialkylamines such as N-methyl glucamine (especially N-methyl D-glucamine), trialkylamines, and substituted trialkylamines); and salts comprising amino acids such as arginine, lysine and so forth. The basic nitrogen-containing groups may be quatemized with agents such as lower alkyl halides (e.g. methyl, ethyl. propyl, and butyl chlorides, bromides and iodides), dialkyl sulfates (e.g. dimethyl, diethyl, dibutyl, and diamyl sulfates), long chain halides (e.g. decyl, lauryl, myrtistyl and stearyl chlorides, bromides and iodides), arylalkyl halides (e.g. benzyl and phenethyl bromides), and others known in the art.  
      Prodrugs and solvates of the macromolecules of the present invention are also contemplated herein. The term “prodrug” as used herein, is understood as being a compound which, upon administration to a subject, such as a mammal, undergoes chemical conversion by metabolic or chemical processes to yield a compound any of the formulas herein, or a salt and/or solvate thereof (Bundgaard, 1991; Bundgaard, 1985). Solvates of the macromolecules of the present invention are preferably hydrates.  
      The claimed invention is also intended to encompass pharmaceutically acceptable salts of any of the synthesized macromolecules of the present invention. The term “pharmaceutically acceptable salts” refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium and sodium salts.  
      Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, and basic ion exchange resins, such as arginine, betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropyulamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like.  
      When a macromolecule of the present invention is basic, salts may be prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include, but are not limited to, acetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid, and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric and tartaric acids.  
      As used herein, the term “alkyl,” alone or in combination, refers to a straight-chain or branched-chain alkyl radical containing from 1 to 10, preferably from 1 to 6 and more preferably from 1 to 4, carbon atoms. Examples of such radicals include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, decyl and the like. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “alkenyl,” alone or in combination, refers to a straight-chain or branched-chain alkenyl radical containing from 2 to 10, preferably from 2 to 6 and more preferably from 2 to 4, carbon atoms having one or more double bonds. Examples of such radicals include, but are not limited to, ethenyl, E- and Z-propenyl, isopropenyl, E- and Z-butenyl, E- and Z-isobutenyl, E- and Z-pentenyl, decenyl and the like. Preferred alkenyl radicals are straight-chain radicals of 3 to 5 carbon atoms and having one double bond. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “alkynyl,” alone or in combination, refers to a straight-chain or branched-chain alkynyl radical containing from 2 to 10, preferably from 2 to 6 and more preferably from 2 to 4, carbon atoms having one or more triple bonds. Examples of such radicals include, but are not limited to, ethynyl (acetylenyl), propynyl, propargyl, butynyl, hexynyl, decynyl and the like. Such radicals may be substituted with groups other than hydrogen, such as alkyl, alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “cycloalkyl,” alone or in combination, refers to a cyclic alkyl radical containing from 3 to 8, preferably from 3 to 6, carbon atoms. Examples of such cycloalkyl radicals include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like. Such radicals may be substituted with groups other than hydrogen, such as alkyl, alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “cycloalkenyl,” alone or in combination, refers to a cyclic carbocycle containing from 4 to 8, preferably 5 or 6, carbon atoms and one or more double bonds. Examples of such cycloalkenyl radicals include, but are not limited to, cyclopentenyl, cyclohexenyl, cyclopentadienyl and the like. Such radicals may be substituted with groups other than hydrogen, such as alkyl, alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “aryl” refers to a carbocyclic aromatic group selected from the group consisting of phenyl, naphthyl, indenyl, indanyl, azulenyl, fluorenyl, and anthracenyl; or a heterocyclic aromatic group selected from the group consisting of furyl, thienyl, pyridyl, pyrrolyl, oxazolyly, thiazolyl, imidazolyl, pyrazolyl, 2-pyrazolinyl, pyrazolidinyl, isoxazolyl, isothiazolyl, 1,2,3-oxadiazolyl, 1,2,3-triazolyl, 1,3,4-thiadiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1,3,5-triazinyl, 1,3,5-trithianyl, indolizinyl, indolyl, isoindolyl, 3H-indolyl, indolinyl, benzo[b]furanyl, 2,3-dihydrobenzofuranyl, benzo[b]thiophenyl, 1H-indazolyl, benzimidazolyl, benzthiazolyl, purinyl, 4H-quinolizinyl, quinolinyl, isoquinolinyl, innolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 1,8-naphthyridinyl, pteridinyl carbazolyl, acridinyl, phenazinyl, phenothiazonyl, and phenoxazinyl.  
      “Aryl” groups, as defined in this application may independently contain one or more substituents. Such substituents may comprise any substituent known to those of skill in the art, and may be further substituted. Non-limiting examples of such substituents include hydrogen, alkyl, alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, phosphino, Ar′-substituted alkyl, Ar′-substituted alkenyl or alkynyl, 1,2-dioxymethylene, 1,2-dioxyethylene, alkoxy, alkenoxy or alkynoxy, Ar′-substituted alkoxy, Ar′-substituted alkenoxy or alkynoxy, alkylamino, alkenylamino or alkynylamino, Ar′-substituted alkylamino, Ar′-substituted alkenylamino or alkynylamino, Ar′-substituted carbonyloxy, alkylcarbonyloxy, aliphatic or aromatic acyl, Ar′-substituted acyl, Ar′-substituted alkylcarbonyloxy, Ar′-substituted carbonylamino, Ar′-substituted amino, Ar′-substituted oxy, Ar′-substituted carbonyl, alkylcarbonylamino, Ar′-substituted alkylcarbonylamino, alkoxy-carbonylamino, Ar′-substituted alkoxycarbonyl-amino, Ar′-oxycarbonylamino, alkylsulfonylamino, mono- or bis-(Ar′-sulfonyl)amino, Ar′-substituted alkylsulfonylamino, morpholinocarbonylamino, thiomorpholinocarbonylamino, N-alkyl guanidino, N-Ar′ guanidino, N-N-(Ar′,alkyl) guanidino, N,N-(Ar′,Ar′)guanidino, N,N-dialkyl guanidino, N,N,N-trialkyl guanidino, N-alkyl urea, N,N-dialkyl urea, N-Ar′ urea, N,N-(Ar′,alkyl) urea and N,N-(Ar′) 2  urea; wherein “Ar′” is a carbocyclic or heterocyclic aryl group as defined optionally substituted with one or more groups selected from the group consisting of hydrogen, halogen, hydroxyl, amino, nitro, trifluoromethyl, trifluoromethoxy, alkyl, alkenyl, alkynyl, 1,2-dioxymethylene, 1,2-dioxyethylene, alkoxy, alkenoxy, alkynoxy, alkylamino, alkenylamino or alkynylamino, alkylcarbonyloxy, aliphatic or aromatic acyl, alkylcarbonylamino, alkoxycarbonylamino, alkylsulfonylamino, N-alkyl or N,N-dialkyl urea.  
      The term “oxy,” alone or in combination, refers to an oxygen-containing radical. Examples of suitable oxy groups are ethers, hydroxyls, carbonyls, and oxocarbonyls.  
      The term “alkoxy,” alone or in combination, refers to an alkyl ether radical, wherein the term “alkyl” is as defined above. Examples of suitable alkyl ether radicals include, but are not limited to, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy and the like. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “alkenoxy,” alone or in combination, refers to a radical of formula alkenyl-O—, wherein the term “alkenyl” is as defined above provided that the radical is not an enol ether. Examples of suitable alkenoxy radicals include, but are not limited to, allyloxy, E- and Z-3-methyl-2-propenoxy and the like. The term “alkynyloxy”, alone or in combination, refers to a radical of formula alkynyl-O—, wherein the term “alkynyl” is as defined above. Examples of suitable alkynoxy radicals include, but are not limited to, propargyloxy, 2-butynyloxy and the like. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “thioalkoxy,” alone or in combination, refers to a thioether radical of formula alkyl-S—, wherein alkyl is as defined above. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “amino,” alone or in combination, is used interchangeably with “amine” and refers to a primary (e.g., —NH 2 ), secondary (e.g., alkyl-NH—), tertiary (e.g., (alkyl)2-N—), and quarternary (e.g., (alkyl) 3 -N(+)-) amine radicals.  
      The term “alkylamino,” alone or in combination, refers to a mono- or di-alkyl-substituted amino radical (i.e., a radical of formula alkyl-NH— or (alkyl) 2 -N—), wherein the term “alkyl” is as defined above. Examples of suitable alkylamino radicals include, but are not limited to, methylamino, ethylamino, propylamino, isopropylamino, t-butylamino, N,N-diethylamino and the like. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “alkenylamino,” alone or in combination, refers to a radical of formula alkenyl-NH— or (alkenyl) 2 N—, wherein the term “alkenyl” is as defined above, provided that the radical is not an enamine. An example of such alkenylamino radicals is the allylamino radical. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “alkynylamino,” alone or in combination, refers to a radical of formula alkynyl-NH— or (alkynyl) 2 N—, wherein the term “alkynyl” is as defined above, provided that the radical is not an ynamine. An example of such alkynylamino radicals is the propargyl amino radical. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “aryloxy,” alone or in combination, refers to a radical of formula aryl-O—, wherein aryl is as defined above. Examples of aryloxy radicals include, but are not limited to, phenoxy, naphthoxy, pyridyloxy and the like. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “arylamino,” alone or in combination, refers to a radical of formula aryl-NH—, wherein aryl is as defined above. Examples of arylamino radicals include, but are not limited to, phenylamino (anilido), naphthylamino, 2-, 3- and 4-pyridylamino and the like. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “biaryl,” alone or in combination, refers to a radical of formula aryl-aryl-, wherein the term “aryl” is as defined above. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      The term “amido,” alone or in combination, refers to a radical of formula —C(═O)—NH—. Examples of suitable amido-containing radicals include, but are not limited to, amino acids, peptides, proteins and the like.  
      The term “aryl-fused cycloalkyl,” alone or in combination, refers to a cycloalkyl radical which shares two adjacent atoms with an aryl radical, wherein the terms “cycloalkyl” and “aryl” are as defined above. An example of an aryl-fused cycloalkyl radical is the benzo-fused cyclobutyl radical. Such radicals may be substituted with groups other than hydrogen, such as alkenyl, alkynyl, aryl, amino, halogen, cyano, thio (e.g., thioether, sulfhlydryl), oxy (e.g., ether, hydroxy), alkoxy, carboxy, oxocarboxy, and phosphino.  
      A “substitutable group” is a group that may be substituted by another group in a chemical reaction. Examples of substitutable groups include halides and leaving groups, as defined below. In a preferred embodiment, the substitutable group is chloro.  
      The term “halogen” or “halo” means fluorine (fluoro), chlorine (chloro), bromine (bromo) or iodine (iodo).  
      The term “leaving group” generally refers to groups readily displaceable by a nucleophile, such as an amine, and alcohol or a thiol nucleophile. Such leaving groups are well known and include carboxylates, N-hydroxysuccinimide, N-hydroxybenzotriazole, halogen (halides), triflates, tosylates, mesylates, alkoxy, thioalkoxy and the like.  
      The term “functional group” generally refers to how persons of skill in the art classify chemically reactive groups. Examples of functional groups include hydroxyl, amine, sulfhydryl, amide, carboxyls, carbonyls, etc.  
      The term “triazine” refers to a heteroaryl containing three nitrogens. Such triazines are well known and include 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, and 1,3,4-triazine.  
      The term “unreactive group” generally refers to a group that does not interfere with or impede the desired transformation of any subsequent reaction.  
      The term “diversity group” generally refers to any carbon-containing or non-carbon containing group that may be attached to a macromolecule. Examples of diversity groups include proteins, peptides, carbohydrates, enzymes, antibodies, antibacterial agents, antibiotics, antiviral agents, antifungal agents, anticancer agents, tumor markers, cell targeting ligands, DNA intercalators, organ-specific ligands, compatibilizing groups and the like.  
      A convergent synthesis starts with surface groups and through iterative reactions, arrives at larger species that are appended to a central core.  
      A divergent synthesis starts with a core and does an increasing number of reactions until some (usually large) number of surface grousp are appended.  
      The term “generation” generally refers to the formation of a macromolecule, such as a dendrimer. Dendrimer, from the Greek word (dendron) for tree, refers to a synthetic, three-dimensional molecule with branching parts. Dendrimers are formed using a nanoscale, multistep fabrication process. Each step results in a new “generation” that has twice the complexity of the previous generation—a first generation dendrimer is the simplest; a tenth generation dendrimer is the most complex and can take months to engineer. Certain dendrimers are called star, dendritic and hybrid macromolecules. Thus, any one macromolecule may consist of one or more generations.  
      The term “nucleophile” or “nucleophilic” generally refers to atoms bearing lone pairs of electrons. Such terms are well known in the art and include —NH 2 , thiolate, carbanion, and alcoholate (also known as hydroxyl).  
      The term “nucleophile-bearing core” refers to a core group which bears one or more nucleophilic groups. Each nucleophilic group may be protected by a protecting group.  
      The term “electrophilic” and generally refers to species that react with nucleophiles. Electrophilic groups typically have a partial postive charge. Such a term is well known in the art and includes the carbon of a carbon bonded to a leaving group such as a halogen or a quarternary amino group.  
      The term “attached” generally refers to one compound being bound to another. Such a term is well known in the art and includes two compounds being covalently bound via, for example, an amide or an ester linkage. Non-covalently bound compounds can also be “attached,” such as when a metal is chelated to another compound.  
      The term “reactive state” refers to a functional group that is prone to participating in a reaction, wherein that participation preferably comprises initiating the reaction.  
      The term “compatibilizing group” generally refers to a group that conveys a specific property to the macromolecule including but not limited to increasing its solubility in water and/or rendering the macromolecule less antigenic and/or affecting the biodistribution.  
      The term “iterative steps” generally refers to repetitious cycling of a series of reactions used in general to increase size (generation) or complexity of a molecule; such series of reactions are not necessarily identical in nature or reactants but follow a general discernible theme.  
      As used throughout this application, the term “mammals” comprises humans. And the term “cell” refers to mammalian cells, including human cells.  
      In view of the above definitions, other chemical terms used throughout this application can be easily understood by those of skill in the art. Terms may be used alone or in any combination thereof. The preferred and more preferred chain lengths of the radicals apply to all such combinations.  
      Other features or advantages of the present invention will be apparent from the following detailed description of several embodiments, and also from the appending claims.  
      It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method or composition of the invention, and vice versa. Furthermore, compositions of the invention can be used to achieve methods of the invention.  
      The term “about” or “approximately” are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.  
      The terms “interference,” “inhibiting,” “reducing,” or “prevention,” or any variation of these terms, when used in the claims and/or the specification includes any measurable decrease or complete inhibition to achieve a desired result.  
      The term “effective,” as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.  
      The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” 
      The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.” 
      As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.  
      Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the examples, while indicating specific embodiments of the invention, are given by way of illustration only. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS  
      The following information provides additional information regarding various aspects of the macromolecules of the present invention.  
      A. Exemplary Applications of Macromolecules of the Present Invention  
      The present invention relates generally to synthetic routes for obtaining functional group diversity in macromolecules and to functionally diverse macromolecules. This diversity permits the facile introduction of a variety of diversity groups at multiple positions of these macromolecules, thereby setting the stage for further generational growth of the macromolecule and/or incorporation of other groups such as biocompatible targeting groups.  
      The inventors have identified means of providing facile divergent synthetic methods for the preparation of functionally diverse macromolecules as single-molecule chemical entities. In certain non-limiting aspects, the macromolecules display a variety of diversity groups at multiple positions, thereby setting the stage for further generational growth of the macromolecule and/or incorporation of other diversity groups such as biocompatible targeting groups. Diversity groups, as defined above, generally refers to any carbon-containing or non-carbon containing group that may be attached to a macromolecule. In some embodiments, the diversity group terminates in a functional group that may be further functionalized with yet another diversity group. Other examples of diversity groups include proteins, peptides, carbohydrates, enzymes, antibodies, antibacterial agents, antibiotics, antiviral agents, antifungal agents, anticancer agents, tumor markers, cell targeting ligands, DNA intercalators, organ-specific ligands, compatibilizing groups and the like. Diversity groups may also comprise one or more cosmetic product compounds, targeting ligands, therapeutic agents and imaging moieties as described below.  
      Macromolecules of the present invention may comprise one or more diversity groups. Many macromolecules known in the art bear two or fewer diversity groups. Macromolecules featuring three or more diversity groups are more attractive as polymeric therapeutics, as more sites are available for conjugation of biocompatible groups, reporter groups to indicate biodistribution, and pharmacologically active molecules.  
      For example, if a macromolecule features a diversity group that is incompatible with a particular environment, the availability of diversifying other portions of the macromolecule to encourage compatibility with the particular environment is a useful application of these macromolecules.  
      Other uses for macromolecules of the present invention include molecular recognition, supramolecular self-assembly, decoration of inorganic groups, energy harvesting and emitting applications, surfactants and medicinal applications. Exemplary applications of macromolecules described below may provide guidance for applications of macromolecules of the present invention. For example, diversity groups found in these applications may be appended to macromolecules of the present invention in order to generate macromolecules that may be used in such applications. Methods of incorporation of such diversity groups into macromolecules of the present invention may be understood either from these applications and/or from synthetic organic techniques known to those of skill in the art.  
      One of the applications of smaller generation triazine-decorated dendrimers pioneered by Wuest and co-workers has been their use as tectons in solid state networks of controlled porosity. Burnet et al., 1997 and Le Fur et al., 2003. The initial report detailed the use of a tecton which was prepared by the cycloaddition of the precursor nitrile with dicyandiamide in 90% yield. Interestingly, when this tecton was crystallized from solutions of formic acid and dioxane, inclusion solids resulted which appear to be relatively insensitive to the guest due to an unusually robust hydrogen bond network. The cycloaddition method was also used to produce boron-containing tectons, and larger dendritic tectons which in turn produced solid state networks of high porosity. The authors observed that when the dendritic nature of the tecton increased, an increase in the number of hydrogen bonds did not necessarily correlate with increased stability following attempted guest-exchange experiments, nor a higher porosity network. Using a different synthetic approach, nucleophilic aromatic substitution was also exploited to prepare tectons. In one case the triazine ring was substituted by three different functional groups which gave rise to a solid state network comprised of interconnected helical channels when crystallized from a solution of acetone, DMSO and water. The development of this technology has already demonstrated potential in practical applications, particularly for use as phase changing inks in ink jet printing.  
      Dendrimers based on melamine also aggregate in solution due to the extensive hydrogen bonding sites that are available. Remarkably, addition of copper (II) to a solution of a dendrimer comprising triazines linked by p-aminobenzyl groups induces a line sharpening effect in size exclusion chromatography (SEC) traces. Zhang et al., 2001. In related work, the SEC trace obtained for a dendrimer where the interior and peripheral groups had N—H sites available to participate in hydrogen bonding had characteristically broad peaks when the analysis was performed in acidified solvents. However, when neutral solvents were used, a similar line sharpening effect was observed and the sample eluted with longer retention times than in acidified solvents. Zhang et al., 2002. These results are consistent with the formation of higher molecular weight material in acidified solvents, and gels of certain dendrimers were observed under these conditions. No gelation of smaller dendrimers nor dendrimers deficient in hydrogen bond sites was observed.  
      Dendritic resins with the triazine unit tethered to an alcohol-functionalized Wang resin have been prepared for the explicit purpose of capitalizing on the ability of melamine dendrimers to scavenge protons. Marsh et al., 2001. The dendritic dichlorotriazine precursors were also examined to determine their ability to scavenge amines from solution. Both materials performed with similar efficiency as commercially available scavenging resins, but at significantly lower concentration due to the relative increase in reactive functional groups per gram of resin.  
      The patent literature has many accounts that detail the use of dendritic materials to modify silica surfaces for various purposes. Recently, Su and co-workers reported a fourth generation melamine dendrimer that was synthesized on a treated silica surface by an iterative process where 1,6-diaminohexane and cyanuric chloride were alternated to generate a dendrimer with amine groups at the periphery. Wu et al., 2003. The modified silica gel was used in a microcolumn to effect preconcentration and separation of platinum from heterogeneous samples, demonstrating potential utility in analytical applications. We have also prepared third and fourth generation dendrimers on a treated silica surface using piperazine (Acosta et al., 2005) and 4-aminomethylpiperidine (Acosta et al., 2004), respectively, as diamine links to the triazine units. A comparison was made where the dendrimers with piperazine as the diamine were synthesized and characterized by a convergent method in solution and then tethered to the silica support, as opposed to being prepared in a divergent fashion directly on the silica surface. TGA evidence demonstrated that the materials with dendrimers that were synthesized using a convergent method had less organic content while the materials with dendrimers synthesized using a divergent method had structural defects. Both of the materials, however, sequestered atrazine, a monochlorotriazine, from aqueous solution, demonstrating their utility as solid-state scavenging reagents.  
      Recently, the research groups of Gamez and Reedikj have designed and prepared a series of ligands by nucleophilic aromatic substitution based on the triazine scaffold, several of which are dendritic in nature. de Hoog et al., 2002; Gamez et al., 2003. When these ligands were treated with copper (II) in water, the catalyst systems that were generated in situ successfully performed the oxidation of 3,5-di-t-butylcatechol. The copper complex generated from a particular ligand resulted in the most active and most stable catalyst system, and the authors attribute this observation to additional stabilization of the active catalyst through the use of a dendritic ligand.  
      One of the earliest research papers to describe the incorporation of triazine in a dendrimer was published in 1998 as a potential light-harvesting antenna. Kraus et al., 1998. The first generation dendrimer had six surface groups that were tethered to triazine branching units through a silyloxy phthalocyanine bond. In a related report, Burn and coworkers used the alkoxy and aryloxy substitution of cyanuric chloride to form the surface groups of a dendrimer linked by a distyrylbenzene core. Lupton et al., 2000; Samuel et al., 1999. The electroluminescence was investigated to determine its potential as a light emitting diode (LED) by preparing luminescent films from the dendritic material. The devices had external quantum efficiencies of 0.003%, but only limited stability, therefore the authors suggested that a subsequent device might perform better if they incorporated a dendritic linkage without the phenoxy group present. More recently, a series of linear and dendritic polymers based on the triazine unit were investigated for integrated optics applications. Dreyer et al., 2003. Preliminary examination of the materials indicates that they have good thermal stability and optical losses at 1550 nm of 0.28-0.44 dB/cm.  
      Limited data exists that details the use of dendritic materials with incorporated triazine units for use as surfactants. A preliminary account details the syntheses of generation zero and first generation-type dendrimers based on a triazine core that display a high number of alcohol functional groups for use as a non-ionic surfactant. Finn et al., 1999; PCT International Pub. No. WO 00/55111. We reported evidence for a new organoclay morphology when smectite clay was treated with a modified version of a dendritic surfactant. Acosta et al., 2003a; Acosta et al., 2003b. This evidence originates in part from X-ray powder diffraction data which indicates a small increase in the interlayer distance of the clay. In addition, IR spectroscopy of the clay with a surfactant larger than certain dendrimers showed that a significant amount of water remained in the interlayer space. TGA corroborated this observation: a minimal amount of organic content is present. For this reason, the phrase “frustrated intercalation” was used to explain the non-traditional behavior of the clay-surfactant composite, wherein only a portion of the surfactant could penetrate the interlayer space.  
      Specific cases have been reported where a dendritic structure containing multiple triazine groups has displayed efficacy as anti-viral agents. U.S. Pat. No. 5,852,015. In 1992, Wyeth-Ayerst initiated a program to identify novel inhibitors of the human respiratory syncytial virus (RSV). Gazumyan et al., 2000. The only active compound identified from screening a library of 20,000 compounds using a whole virus and cell-based assay was a dendritic structure. The identified compound, termed CL 309623, contains a disulfonated stilbene core with a triazine tethered at each end installed using standard nucleophilic aromatic substitution protocols. This class of compounds was originally reported in 1962 as a potential optical brighteners. Gehn et al., 1962. A patent was filed in 1997 to use CL 309623 and related derivatives to treat viral infections. U.S. Pat. No. 5,852,015. In 1998, a comprehensive structure-activity relationship study was undertaken, which resulted in the identification of even more potent molecules, all of which retained two triazine units. Ding et al., 1998. An extension of this study conducted in 2001 identified RFI-641 as a potent and selective inhibitor of RSV. Huntley et al., 2002. The mode of action of these dendrimer-like compounds is interruption of F-protein mediated cell fusion of RSV with the target cell through a specific interaction of the anti-viral agent with the fusion protein of the RSV virus.  
      Promising triazine-based antibiotics have been developed by examining them as part of a dendrimer bound to a poly(styrene) resin. Bell et al., 2003. The dendrimer was not constructed from repeating triazine units, but instead had a variety of triazine derivatives were tethered to the periphery. A modified second generation Newkome-type dendrimer with nine surface amines was constructed on a solid polystyrene support, effectively increasing the loading capacity of the resin. The surface amines were modified to present a phenol, and then treated with cyanuric chloride. This resulted in the incorporation of nine dichlorotriazine units at the surface of each dendron. These dendrons were subsequently treated with various amine nucleophiles to produce a library of compounds. The triazines were liberated from the solid support by heating the resin in the presence of morpholine or piperidine since the aryloxy-triazine bond is susceptible to attack by these secondary amines. This design permitted single-bead screening of a library of potential antibiotics, and thus represents a significant advance in this type of assay since a higher concentration of the agent of interest could be produced due to the dendritic nature of the resin.  
      A significant advance in the application of triazine-based dendrimer chemistry has been the preparation of dendrimers that present disulfide linkages at the periphery. Several precursor dendrimers and dendrons, which were prepared using the nucleophilic aromatic substitution strategy, were decorated with pyridyl disulfide groups at the periphery or at the terminal of a dendron. These disulfide groups readily underwent exchange with biotin, captopril, a small peptide sequence, or even a DNA oligonucleotide, although characterization and purification of the latter was challenging, and no general protocols emerged. Steffensen et al., 2004; Umali et al., 2003; Bell et al., 2003.  
      Qualitative observations resulting from these experiments indicated that steric factors arising from the size of the substrate or the dendrimer influenced the degree of exchange that occurred. A related kinetic study of disulfide exchange on the periphery of other melamine-derived dendrimers confirmed that the rate of exchange increases as the size of the dendrimer decreases. Zhang et al., 2003. Interestingly, in the two cases that were followed by mass spectrometry, rate constants were identical within a factor of 100× for each of the disulfides of a dendrimer, but increased as dansyl groups were shed from the architecture. These findings are intriguing: disulfide linkages can be used to tether pharmacophores, targeting agents, or imaging agents to a dendrimer for drug delivery and in vivo monitoring applications.  
      Another method of drug delivery that could be facilitated by dendrimers is through non-covalent transport and delivery. To this end, a preliminary study showed that treatment of a cationic melamine-based dendrimer sequestered drugs as a function of drug composition when mixed with indomethacin, methotrexate or 10-hydroxycamptothecin. Zhang et al., 2003. The degree of solubilization was dependent on the properties of the drug; only in the case of 10-hydroxycamptothecin and a bis-indole methane was any significant solubility enhancement observed (3.7 molecules of drug solubilized/dendrimer). However, studies with pyrene showed that for dendrimers of related molecular weights, triazine dendrimers performed similarly to Frèchet&#39;s original arylethers by solubilizing 0.1 and 0.2 molecules of pyrene/dendrimer. This represents a 10-20× increase over the more hydrophilic poly(amidoamine) and poly(propyleneimine) dendrimers.  
      To more thoroughly examine the toxicity of melamine-derived dendrimers in vitro and in vivo, seven different dendrimers were prepared that displayed groups at the periphery which were either cationic, anionic, or neutral, and could still convey sufficient solubility in water. Chen et al., 2004. The results of the cell viability study indicated that the neutral dendrimer decorated with poly(ethylene glycol) (PEG) was the least hemolytic over a concentration range of 0.001-10 mg/mL. Subsequent acute dosing experiments with the PEG-functionalized dendrimer indicated no toxicity in mice at concentrations up to 2.56 g/kg (ip administration) or 1.28 g/kg (iv administration). Related studies with a cationic dendrimer demonstrated no detectable toxicity in vivo until mice were dosed with 40 mg/kg. Neerman et al., 2004. Additional recent results are promising since the data suggest that the hepatoxicity of the anti-cancer drugs methotrexate and 6-mercaptopurine were reduced upon non-covalent encapsulation of these pharmacophores by a melamine-based dendrimer. The accumulation of this data and other animal studies (Neerman et al., 2005) suggests that dendrimers based on melamine have potential for a variety of biomedical applications.  
      The use of triazine derivatives in an enormous number of applications is well documented. However, since the advent of dendrimer chemistry, the role of triazines as potential constructs for the synthesis of dendritic materials had initially been limited. Recently, the benefits that arise from both the structural complexity and ease of synthetic manipulation that can be achieved using triazine units as building blocks have caught the interest of an increasing number of research groups in industrial and academic settings. In a relatively short period of time, synthetic strategies have been developed, and a number of applications are currently being investigated where triazine-based dendritic materials play an essential role. It is likely that the convergence of co-invention and rediscovery that has occurred with triazine-based dendritic materials will only continue to generate interesting materials for current applications and result in the development of new applications.  
      B. Synthetic Details  
      Macromolecules can be prepared via convergent or divergent syntheses. A convergent synthesis starts with surface groups and through iterative reactions, arrives at larger species that are appended to a central core. A divergent synthesis starts with a core and does an increasing number of reactions until some (usually large) number of surface groups are appended. The methods of the present invention relate to divergent syntheses.  
      Divergent syntheses of macromolecules as shown by this invention offer an advantage to many convergent syntheses known in the art as well as some divergent syntheses: the macromolecules of the present invention can be obtained as single-chemical entities (ie. high chemical purity). This is an attractive feature, especially for biomedical applications.  
      Generally speaking, macromolecules of the present invention are prepared by treatment of the poly(nucleophilic) core with monomeric electrophilic triazines to cleanly yield poly(monomeric electrophilic triazines). As defined above, the term “nucleophile” or “nucleophilic” generally refers to atoms bearing lone pairs of electrons. Such terms are well known in the art and include —NH 2 , thiolate, carbanion, and alcoholate (also known as hydroxyl). In preferred embodiments, the nucleophilic group comprises —NH 2 . Subsequent nucleophilic reactions with, for example, amine nucleophiles bearing a functional group or diversity group of interest yield diversity. Typically, the reaction proceeds via nucleophilic aromatic substitution, a mechanistic pathway well known to those of skill in the art. If a substituent on any one monomeric electrophilic triazines is a protected nucleophile, removal of the functional group allows for iterative reactions and the synthesis of, for example, star, dendritic and hybrid macromolecules. Protecting groups for the generation of protected nucleophiles and the like are detailed below.  
      The syntheses of these compounds proceed efficiently and with effective chromatography to produce single-chemical species. A nucleophilic core such as a triazine-based core can be reacted in the presence of a mild base such as diisopropylethylamine in the presence of monomeric electrophilic triazines at low temperatures (e.g., 0° C.) the solution of which may be warmed over time, as described herein, to room temperature, to produce first generation macromolecules. The reaction time may range anywhere from 1 minute to 72 hours, with reaction times of 12 to 24 hours being preferred. Reaction progress can be monitored by thin-layer chromatography (TLC) in most situations, as is known by those of skill in the art. Other appropriate bases may include, for example, nitrogen-containing bases such as pyridine, triethylamine and trimethylamine. Depending on the functionality of the starting triazines, such a macromolecule can bear nucleophilic groups, protected nucleophilic groups as well as diversity groups as described herein. Further iterative reactions of the synthesized molecule can result in larger macromolecules also bearing nucleophilic groups, protected nucleophilic groups as well as diversity groups as described herein. A benefit to such “generational expansion” of the present synthesis lies in the fact that the generated macromolecules are pure and available for further reactions.  
      Solvent choices for the methods of the present invention will be known to one of ordinary skill in the art. Solvent choices may depend, for example, on which one(s) will facilitate the solubilizing of all the reagents or, for example, which one(s) will best facilitate the desired reaction (particularly when the mechanism of the reaction is known). Solvents may include, for example, polar solvents and non-polar solvents. Solvents choices include, but are not limited to, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, dioxane, methanol, ethanol, hexane, methylene chloride and acetonitrile. In some preferred embodiments, the solvent is tetrahydrofuran. More than one solvent may be chosen for any particular reaction or purification procedure. Water may also be admixed into any solvent choice.  
      Not only can a variety of nucleophilic, protected nucleophilic and diversity groups be appended to these macromolecules, but linkers of various lengths can connect one group to the core structure (e.g., one nucleophile-bearing group to a nucleophilic core; a diversity group to a nucleophilic core). This allows for even further extension of the “reach” of each “arm” of any macromolecule of the present invention. Linkers applicable in the methods of the present invention would be known to those of skill in the art. Non-limiting examples of such linkers include a hydrocarbon-containing group (e.g. alkyl), a secondary or tertiary amine-containing group, an oxo-containing group (e.g. ether), a thiol-containing group (e.g., thioether) an amido-containing group, a phosphino-containing group, and any combination of one or more of these groups. In preferred embodiments, the linker comprises a moiety selected from the group consisting of:  
                 
 
      Persons of ordinary skill in the art will be familiar with methods of purifying compounds of the present invention. One of ordinary skill in the art will understand that compounds of the present invention can generally be purified at any step, including the purification of intermediates as well as purification of the final products. Non-limiting examples of purification methods include gel filtration, size exclusion chromatography (also called gel filtration chromatography, gel permeation chromatography or molecular exclusion), dialysis, distillation, crystallization, recrystallization, reprecipitation, sublimation, electrophoresis, prep thin-layer chromatography, silica gel column chromatography and high-performance liquid chromatography (HPLC), including normal-phase HPLC and reverse-phase HPLC. In preferred embodiments, purification is performed via reprecipitation, silica gel column chromatography or HPLC.  
      Methods of determining the purity of compounds are well known to those of skill in the art and include, in non-limiting examples, autoradiography, mass spectroscopy, melting point determination, ultra violet analysis, calorimetric analysis, (HPLC), thin-layer chromatography and nuclear magnetic resonance (NMR) analysis (including, but not limited to,  1 H and  13 C NMR). In preferred embodiments, purity is determined via thin-layer chromatography or NMR. Software available on various instruments (e.g., spectrophotometers, HPLCs, NMRs) can aid one of skill in the art in making these determinations, as well as other means known to those of skill in the art.  
      In certain embodiments of the present invention, purification of a compound does not remove all impurities. In some embodiments, such impurities can be identified.  
      C. Protecting Groups  
      When a chemical reaction is to be carried out selectively at one reactive site in a multifunctional compound, other reactive sites must be temporarily blocked. A “protecting group,” or “protected-nucleophilic group” as used herein, is defined as a group used for the purpose of this temporary blockage. During the synthesis of the macromolecules of the present invention, various functional groups must be protected using protecting groups (or protecting agents) at various stages of the synthesis. For example, various positions of a monomeric electrophilic triazine may need to be protected when used in a synthetic procedure (e.g., “a first monomeric electrohilic triazine having one or more protected nucleophilic groups”). When a diversity group is introduced during the synthesis of a macromolecule, that diversity group may also need to be protected by protecting groups (i.e., a “protected diversity group”). However, use of the phrase “protected diversity group” or “protected macromolecule” does not mean that every functional group available to be protected is protected. Functional groups necessary for the desired transformation, for example, should be unprotected.  
      There are a number of methods well known to those skilled in the art for accomplishing such a step. For protecting agents, their reactivity, installation and use, see, e.g., “Protective Groups in Organic Synthesis”, 3 rd  ed., by T. W. Greene and P. G. M. Wuts, John Wiley &amp; Sons, New York, N.Y. (1999), herein incorporated by reference in its entirety. The function of a protecting group is to protect one or more functionalities (e.g., —NH 2 , —SH, —COOH) during subsequent reactions which would not proceed well, either because the free (in other words, unprotected) functional group would react and be functionalized in a way that is inconsistent with its need to be free for subsequent reactions, or the free functional group would interfere in the reaction. The same protecting group may be used to protect one or more of the same or different functional group(s). Also, different protecting groups can be used to protect the same type of functional group within a macromolecule of the present invention in multiple steps.  
      When a protecting group is no longer needed, it is removed by methods well known to those skilled in the art. For deprotecting agents and their use, see, e.g., Greene and Wuts (1999). Agents used to remove the protecting group are sometimes called deprotecting agents. Protecting groups must be readily removable (as is known to those skilled in the art) by methods employing deprotecting agents that are well known to those skilled in the art. It is well known that certain deprotecting agents remove some protective groups and not others, while other deprotecting agents remove several types of protecting groups from several types of functional groups. Thus, a first deprotecting agent may be used to remove one type of protecting group, followed by the use of a second deprotecting agent to remove a second type of protecting group, and so on.  
      In one embodiment of the present invention, the deprotecting agent is the use of concentrated HCl in methanol in order to remove a t-butoxycarbonyl group to reveal a free amine (—NH 2 ). Persons of ordinary skill in the art will be familiar with the proper ordering of protective group removal using deprotecting agents. See e.g., Greene and Wuts (1999). Particular non-limiting examples of protecting groups are discussed below.  
      1. Amino Protecting Groups  
      Amino protecting groups are well known to those skilled in the art. See, for example, Greene and Wuts (1999) Chapter 7.  
      A suitable amino protecting group may be selected from the group consisting of t-butoxycarbonyl, benzyloxycarbonyl, formyl, trityl, acetyl, trichloroacetyl, dichloroacetyl, chloroacetyl, trifluoroacetyl, difluoroacetyl, fluoroacetyl, benzyl chloroformate, 4-phenylbenzyloxycarbonyl, 2-methylbenzyloxycarbonyl, 4-ethoxybenzyloxycarbonyl, 4-fluorobenzyloxycarbonyl, 4-chlorobenzyloxycarbonyl, 3-chlorobenzyloxycarbonyl, 2-chlorobenzyloxycarbonyl, 2,4-dichlorobenzyloxycarbonyl, 4-bromobenzyloxycarbonyl, 3-bromobenzyloxycarbonyl, 4-nitrobenzyloxycarbonyl, 4-cyanobenzyloxycarbonyl, 2-(4-xenyl)isopropoxycarbonyl, 1,1-diphenyleth-1-yloxycarbonyl, 1,1-diphenylprop-1-yloxycarbonyl, 2-phenylprop-2-yloxycarbonyl, 2-(p-toluyl)prop-2-yloxycarbonyl, cyclopentanyloxycarbonyl, 1-methylcyclopentanyloxycarbonyl, cyclohexanyloxycarbonyl, 1-methylcyclohexanyloxycabonyl, 2-methylcyclohexanyloxycarbonyl, 2-(4-toluylsulfonyl)ethoxycarbonyl, 2-(methylsulfonyl)ethoxycarbonyl, 2-(triphenylphosphino)ethoxycarbonyl, fluorenylmethoxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, allyloxycarbonyl, 1-(trimethylsilylmethyl)prop-1-enyloxycarbonyl, 5-benzisoxalylmethoxycarbonyl, 4-acetoxybenzyloxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-ethynyl-2-propoxycarbonyl, cyclopropylmethoxycarbonyl, 4-(decyloxyl)benzyloxycarbonyl, isobomyloxycarbonyl, 1-piperidyloxycarbonyl and 9-fluorenylmethyl carbonate, for example. In certain embodiments of the present invention, the amine protecting group is t-butoxycarbonyl.  
      2. Thiol Protecting Groups  
      Thiol protecting groups are well known to those skilled in the art. See, for example, Greene and Wuts (1999) Chapter 6.  
      A suitable thiol protecting group may be selected from the group consisting of acetamidomethyl, benzamidomethyl, 1-ethoxyethyl, benzoyl, triphenylmethyl, t-butyl, benzyl, adamantyl, cyanoethyl, acetyl, and trifluoroacetyl, for example.  
      3. Alcohol Protecting Groups  
      Alcohol protecting groups are well known to those skilled in the art. See, for example, Greene and Wuts (1999) Chapter 2.  
      A suitable alcohol protecting group may be selected from the group consisting of methoxymethyl, (phenyldimethylsilyl)methoxymethyl, benzyloxymethyl, t-butoxymethyl, and tetrahydropyranyl, for example.  
      4. Carboxylic Acid Protecting Groups  
      Carboxylic acid protecting groups are well known to those skilled in the art. See, for example, Greene and Wuts (1999) Chapter 5.  
      A suitable carboxylic acid protecting group may be selected from the group consisting of dimethylacetal, methoxymethylester, phenylacetoxymethyl ester and tetrahydropyranyl ester, for example.  
      5. Carbonyl Protecting Groups  
      Carbonyl protecting groups are well known to those skilled in the art. See, for example, Greene and Wuts (1999) Chapter 4.  
      A suitable carbonyl protecting group may be selected from the group consisting of dimethylacetal, dimethylketal, diisopropylacetal, diisopropylketal, enamines and enol ethers, for example.  
      D. Source of Compounds, Agents, and Active Ingredients  
      The compounds, agents, and active ingredients (e.g., solvents, catalysts, bases used in reactions, and other compounds, agents, and active ingredients described herein) that are described in the claims and specification can be obtained by any means known to a person of ordinary skill in the art. In a non-limiting embodiment, for example, the compounds, agents, and active ingredients can be isolated by obtaining the source of such compounds, agents, and active ingredients. In many instances, the compounds, agents, and active ingredients are commercially available (e.g., Sigma-Aldrich, Milwaukee, Wis.).  
      E. Modifications and Derivatives  
      Modifications or derivatives of the compounds, agents, and active ingredients disclosed throughout this specification are contemplated as being useful with the methods and compositions of the present invention. Derivatives may be prepared and the properties of such derivatives may be assayed for their desired properties by any method known to those of skill in the art.  
      In certain aspects, “derivative” refers to a chemically modified compound that still retains the desired effects of the compound prior to the chemical modification. Such derivatives may have the addition, removal, or substitution of one or more chemical moieties on the parent molecule. Non limiting examples of the types modifications that can be made to the compounds and structures disclosed herein include the addition or removal of lower alkanes such as methyl, ethyl, propyl, or substituted lower alkanes such as hydroxymethyl or aminomethyl groups; carboxyl groups and carbonyl groups; hydroxyls; nitro, amino, amide, and azo groups; sulfate, sulfonate, sulfono, sulfhydryl, sulfonyl, sulfoxido, phosphate, phosphono, phosphoryl groups, and halide substituents. Additional modifications can include an addition or a deletion of one or more atoms of the atomic framework, for example, substitution of an ethyl by a propyl; substitution of a phenyl by a larger or smaller aromatic group. Alternatively, in a cyclic or bicyclic structure, hetero atoms such as N, S, or O can be substituted into the structure instead of a carbon atom.  
      F. Equivalents  
      Known and unknown equivalents of the specific compounds, agents, and active ingredients discussed throughout this specification can be used with the compositions and methods of the present invention. The equivalents can be used as substitutes for the specific compounds, agents, and active components. The equivalents can also be used to add to the methods and compositions of the present invention. A person of ordinary skill in the art would be able to recognize and identify acceptable known and unknown equivalents to the specific compounds, agents, and active ingredients without undue experimentation.  
      G. Compositions of the Present Invention  
      A person of ordinary skill would recognize that the compounds of the present invention may be formulated into useful compositions, in particular, pharmaceutical (diagnostic or therapeutic) compositions, as such compounds may be modified to include any number of combinations of compounds, agents, and/or active ingredients, or derivatives therein. It is also contemplated that the concentrations of the compounds, agents, and/or active ingredients can vary. In non-limiting embodiments, for example, the compositions may include in their final form, for example, at least about 0.0001% to 99% or any range derivable therein, of at least one of the compounds, agents, active ingredients, or derivatives. In non-limiting aspects, the percentage can be calculated by weight or volume of the total composition. A person of ordinary skill in the art would understand that the concentrations can vary depending on the addition, substitution, and/or subtraction of the compounds, agents, or active ingredients, to the disclosed methods and compositions.  
      H. Vehicles  
      The compositions of the present invention can be incorporated into all types of are effective in all types of vehicles. Non-limiting examples of suitable vehicles include emulsions (e.g., water-in-oil, water-in-oil-in-water, oil-in-water, -oil-in-water-in-oil, oil-in-water-in-silicone emulsions), creams, lotions, solutions (both aqueous and hydro-alcoholic), anhydrous bases (such as lipsticks and powders), gels, and ointments or by other method or any combination of the forgoing as would be known to one of ordinary skill in the art (Remington&#39;s, 1990). Variations and other appropriate vehicles will be apparent to the skilled artisan and are appropriate for use in the present invention. In certain aspects, it is important that the concentrations and combinations of the compounds, ingredients, and active agents be selected in such a way that the combinations are chemically compatible and do not form complexes which precipitate from the finished product.  
      I. Cosmetic Products and Articles of Manufacture  
      The composition of the present invention can also be used in many cosmetic products including, but not limited to, sunscreen products, sunless skin tanning products, hair products, finger nail products, moisturizing creams, skin benefit creams and lotions, softeners, day lotions, gels, ointments, foundations, night creams, lipsticks, cleansers, toners, masks, or other known cosmetic products or applications. Additionally, the cosmetic products can be formulated as leave-on or rinse-off products.  
      J. Targeting Ligands  
      In some embodiments of the compositions of the present invention, a targeting ligand, or more particularly tissue-specific ligands, may be attached to the macromolecule compound. A “tissue-specific ligand” or “tissue-targeting ligand” is defined herein to refer to a part of a molecule that can bind or attach to one or more tissues. The binding may be by any mechanism of binding known to those of ordinary skill in the art (e.g., covalent, non-covalent, associative). Examples include therapeutic agents, antimetabolites, apoptotic agents, bioreductive agents, signal transductive therapeutic agents, receptor responsive agents, or cell cycle specific agents. The tissue may be any type of tissue, such as a cell. For example, the cell may be the cell of a subject, such as a cancer cell. In certain embodiments, the tissue targeting moiety is a tissue targeting amino acid sequence that is chemically conjugated or fused to a macromolecule that is capable of binding to a valent metal ion.  
      Examples of targeting ligands include disease cell cycle targeting compounds, tumor angiogenesis targeting ligands, tumor apoptosis targeting ligands, disease receptor targeting ligands, drug-based ligands, antimicrobials, tumor hypoxia targeting ligands, an agent that mimics glucose, amifostine, angiostatin, EGF receptor ligands, capecitabine, COX-2 inhibitors, deoxycytidine, fullerene, herceptin, human serum albumin, lactose, leuteinizing hormone, pyridoxal, quinazoline, thalidomide, transferrin, and trimethyl lysine.  
      In further embodiments of the present invention, the tissue-specific moiety is an antibody. Any antibody is contemplated as a tissue-targeting moiety in the context of the present invention. For example, the antibody may be a monoclonal antibody. One of ordinary skill in the art would be familiar with monoclonal antibodies, methods of preparation of monoclonal antibodies, and methods of use of monoclonal antibodies as ligands. In certain embodiments of the present invention, the monoclonal antibody is an antibody directed against a tumor marker. In some embodiments, the monoclonal antibody is monoclonal antibody C225, monoclonal antibody CD31, or monoclonal antibody CD40.  
      K. Therapeutic Agents  
      In certain embodiments of the compositions of the present invention, a targeting or tissue-specific ligand is bound to the macromolecule. A “moiety” is defined herein to be a part of a molecule. In certain particular embodiments, the tissue-specific ligand is a therapeutic moiety. A “therapeutic moiety” is defined herein to refer to any therapeutic agent. A “therapeutic agent” is defined herein to include any compound or substance or drug that can be administered to a subject, or contacted with a cell or tissue, for the purpose of treating a disease or disorder, or preventing a disease or disorder, or treating or preventing an alteration or disruption of a normal physiologic process. For example, the therapeutic moiety may be an anti-cancer moiety, such as a chemotherapeutic agent. In certain embodiments of the present invention, the therapeutic moiety is a therapeutic amino acid sequence that is fused or chemically conjugated to the therapeutic amino acid sequence.  
      Examples of anti-cancer moieties include any chemotherapeutic agent known to those of ordinary skill in the art. Examples of such chemotherapeutic agents include, but are not limited to, cisplatin (CDDP), carboplatin, procarbazine, mechlorethamine, cyclophosphamide, camptothecin, ifosfamide, melphalan, chlorambucil, busulfan, nitrosurea, dactinomycin, daunorubicin, doxorubicin, bleomycin, plicomycin, mitomycin, etoposide (VP16), tamoxifen, raloxifene, estrogen receptor binding agents, taxol, gemcitabien, navelbine, farnesyl-protein transferase inhibitors, transplatinum, 5-fluorouracil, vincristin, vinblastin and methotrexate, or any analog or derivative variant of the foregoing. In certain particular embodiments, the anti-cancer moiety is methotrexate.  
      A wide variety of chemotherapeutic agents may be used in accordance with the present invention. The term “chemotherapy” refers to the use of drugs to treat cancer. A “chemotherapeutic agent” is used to connote a compound or composition that is administered in the treatment of cancer. These agents or drugs are categorized by their mode of activity within a cell, for example, whether and at what stage they affect the cell cycle. Alternatively, an agent may be characterized based on its ability to directly cross-link DNA, to intercalate into DNA, or to induce chromosomal and mitotic aberrations by affecting nucleic acid synthesis. Most chemotherapeutic agents fall into the following categories: alkylating agents, antimetabolites, antitumor antibiotics, mitotic inhibitors, and nitrosoureas.  
      Examples of chemotherapeutic agents include alkylating agents such as thiotepa and cyclosphosphamide; alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, trietylenephosphoramide, triethiylenethiophosphoramide and trimethylolomelamine; acetogenins (especially bullatacin and bullatacinone); a camptothecin (including the synthetic analogue topotecan); bryostatin; callystatin; CC-1065 (including its adozelesin, carzelesin and bizelesin synthetic analogues); cryptophycins (particularly cryptophycin 1 and cryptophycin 8); dolastatin; duocarmycin (including the synthetic analogues, KW-2189 and CB1-TM1); eleutherobin; pancratistatin; a sarcodictyin; spongistatin; nitrogen mustards such as chlorambucil, chlornaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, and ranimustine; antibiotics such as the enediyne antibiotics (e.g., calicheamicin, especially calicheamicin gammalI and calicheamicin omegaI1; dynemicin, including dynemicin A; bisphosphonates, such as clodronate; an esperamicin; as well as neocarzinostatin chromophore and related chromoprotein enediyne antiobiotic chromophores, aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, carabicin, carminomycin, carzinophilin, chromomycinis, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin (including morpholino-doxorubicin, cyanomorpholino-doxorubicin, 2-pyrrolino-doxorubicin and deoxydoxorubicin), epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins such as mitomycin C, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5-fluorouracil (5-FU); folic acid analogues such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; eniluracil; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elformithine; elliptinium acetate; an epothilone; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidainine; maytansinoids such as maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidanmol; nitraerine; pentostatin; phenamet; pirarubicin; losoxantrone; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK polysaccharide complex); razoxane; rhizoxin; sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2,2′,2″-trichlorotriethylamine; trichothecenes (especially T-2 toxin, verracurin A, roridin A and anguidine); urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (“Ara-C”); cyclophosphamide; thiotepa; taxoids, e.g., paclitaxel and doxetaxel; chlorambucil; gemcitabine; 6-thioguanine; mercaptopurine; methotrexate; platinum coordination complexes such as cisplatin, oxaliplatin and carboplatin; vinblastine; platinum; etoposide (VP-16); ifosfamide; mitoxantrone; vincristine; vinorelbine; novantrone; teniposide; edatrexate; daunomycin; aminopterin; xeloda; ibandronate; irinotecan (e.g., CPT-11); topoisomerase inhibitor RFS 2000; difluorometlhylomithine (DMFO); retinoids such as retinoic acid; capecitabine; and pharmaceutically acceptable salts, acids or derivatives of any of the above.  
      Also included in this definition are anti-hormonal agents that act to regulate or inhibit hormone action on tumors such as anti-estrogens and selective estrogen receptor modulators (SERMs), including, for example, tamoxifen, raloxifene, droloxifene, 4-hydroxytamoxifen, trioxifene, keoxifene, LY117018, onapristone, and toremifene; aromatase inhibitors that inhibit the enzyme aromatase, which regulates estrogen production in the adrenal glands, such as, for example, 4(5)-imidazoles, aminoglutethimide, megestrol acetate, exemestane, formestanie, fadrozole, vorozole, letrozole, and anastrozole; and anti-androgens such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin; as well as troxacitabine (a 1,3-dioxolane nucleoside cytosine analog); antisense oligonucleotides, particularly those which inhibit expression of genes in signaling pathways implicated in abherant cell proliferation, such as, for example, PKC-alpha, Ralf and H-Ras; ribozymes such as a VEGF expression inhibitor and a HER2 expression inhibitor; vaccines such as gene therapy vaccines and pharmaceutically acceptable salts, acids or derivatives of any of the above.  
      L. Imaging Moieties  
      In certain embodiments of the compositions of the present invention, the tissue-specific ligand is an imaging moiety. As defined herein, an “imaging moiety” is a part of a molecule that is a agent or compound that can be administered to a subject, contacted with a tissue, or applied to a cell for the purpose of facilitating visualization of particular characteristics or aspects of the subject, tissue, or cell through the use of an imaging modality. Imaging modalities are discussed in greater detail below. Any imaging agent known to those of ordinary skill in the art is contemplated as an imaging moiety of the present invention. Thus, for example, in certain embodiments of the compositions of the present invention, the compositions can be applied in multimodality imaging techniques.  
      In certain embodiments, the imaging moiety is a contrast media. Examples include CT contrast media, MRI contrast media, optical contrast media, ultrasound contrast media, or any other contrast media to be used in any other form of imaging modality known to those of ordinary skill in the art. Examples include diatrizoate (a CT contrast agent), a gadolinium chelate (an MRI contrast agent), and sodium fluorescein (an optical contrast media). One of ordinary skill in the art would be familiar with the wide range of types of imaging agents that can be employed as imaging moieties in the macromolecules of the present invention.  
      M. Emulsifiers  
      The compositions of the present invention can also comprise one or more emulsifiers. Emulsifiers can reduce the interfacial tension between phases and improve the formulation and stability of an emulsion. The emulsifiers can be nonionic, cationic, anionic, and zwitterionic emulsifiers (See McCutcheon&#39;s (1986); U.S. Pat. Nos. 5,011,681; 4,421,769; 3,755,560). Non-limiting examples include esters of glycerin, esters of propylene glycol, fatty acid esters of polyethylene glycol, fatty acid esters of polypropylene glycol, esters of sorbitol, esters of sorbitan anhydrides, carboxylic acid copolymers, esters and ethers of glucose, ethoxylated ethers, ethoxylated alcohols, alkyl phosphates, polyoxyethylene fatty ether phosphates, fatty acid amides, acyl lactylates, soaps, TEA stearate, DEA oleth-3 phosphate, polyethylene glycol 20 sorbitan monolaurate (polysorbate 20), polyethylene glycol 5 soya sterol, steareth-2, steareth-20, steareth-21, ceteareth-20, PPG-2 methyl glucose ether distearate, ceteth-10, polysorbate 80, cetyl phosphate, potassium cetyl phosphate, diethanolamine cetyl phosphate, polysorbate 60, glyceryl stearate, PEG-100 stearate, and mixtures thereof.  
     EXAMPLES  
      The following examples are included to demonstrate certain non-limiting aspects of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.  
      With respect to the following Examples,  1 H and  13 C{ 1 H} NMR data were acquired on a Varian 300 MHz spectrometer at RT unless otherwise indicated.  1 H and  13 C{ 1 H} NMR chemical shifts are listed relative to tetramethylsilane in parts per million, and were referenced to the residual proton or carbon peak of the solvent. MS analyses were performed by the Laboratory for Biological Mass Spectrometry at Texas A&amp;M University. All solvents and reagents were purchased from Aldrich Chemical Co. or Acros Organics and were used without purification. The reagents 4, 7 and 13 were prepared by a modification of previously reported methods. Lowik et al., 2001; Chen, et al., 2004; Rannard and Davis, 2004. Thin-layer chromatography was performed using EMD silica gel 60 F 254  pre-coated glass plates (0.25 mm), and preparative chromatography was performed using EMD silica gel 60 (0.040 mm particle size).  
      The following synthetic diagrams, chemical structures and synthetic details provide certain macromolecules of the present invention.  
                 
 
 Synthetic conditions: (a) 4, DIPEA, THF, 0° C.-RT, 16 h. (b) 2 − (2-aminoethoxy)ethanol, DIPEA, THF, 65° C., 24 h. (c) Conc. HCl.MeOH 1.2, RT, 12 h. (d) 4, DIPEA, THF, 0° C.-RT, 16 h. (e) 5, DIPEA, THF, 0° C.-RT, 12 h. (f) 6, DIPEA, THF, 0° C.-RT, 16 h.  
                 
 
      Synthetic conditions: (a) 13, DIPEA, THF, 0° C.-RT, 12 h. (b) 4-amp, THF, RT, 12 h. (c) C 3 N 3 Cl 3 , DIPEA, THF, 0° C.-RT, 12.5 h.  
                                                           Overall           Cmpd   Structure   Steps   Yield a     Columns                                          1                         4   65%   2               2                         4   75%   2               3                         4   74%   2                           a Precluding contributions from the syntheses of 4-7.                                                                                        
 
     Example 1 
                         
 Synthesis of Compound 1: A clear solution of 4 (499 mg, 1.49 mmol) in 50 mL of THF was prepared, and a slurry of (NH) 3 OH 3 .3HCl (530 mg, 0.43 mmol) and DIPEA (0.73 mL, 4.29 mmol) was prepared in 50 mL of THF in a separate flask. Both solutions were cooled to 0° C., then combined. The mixture was warmed gradually to RT and stirred for 16 h, after which time the solvent was removed in vacuo. Purification was achieved using column chromatography on silica gel to afford the product as a white solid (gradient elution from 80:1 CH 2 Cl 2 :MeOH until no detectable 4 was observed as determined using UV spotting to 20:1 CH 2 Cl 2 :MeOH to obtain the desired product; R f =0.24 using 9:1 CH 2 Cl 2 :MeOH as the developing solvent). Yield: 726 mg (84%). The excess/unreacted C 3 N 3 (pip-Boc)Cl 2  was also recovered from this purification (R f =0.90 using 9:1 CH 2 Cl 2 :MeOH as the developing solvent). Yield: 139 mg (99% of unreacted starting material based on recovered yield of star polymer).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.44 (br, 3H, NH), 3.77 (br, 60H+6H, CH 2 ), 3.61 (br, 18H, CH 2 ), 3.44 (br, 12H, CH 2 NBoc), 2.30 (br, 3H, OH), 1.45 (s, 27H, C(CH 3 ) 3 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 169.6 (s, C 3 N 3 ), 165.3 (s, C 3 N 3 ), 164.4 (s, C 3 N 3 ), 154.6 (s, C(O)), 80.2 (s, C(CH 3 ) 3 ), 72.4 (s, OCH 2 CH 2 OH), 70.0 (s, NHCH 2 CH 2 O), 61.6 (s, OCH 2 CH 2 OH), 43.2 and 43.0 (s, CH 2 CH 2 NHBoc, piperazine), 40.5 (s, NHCH 2 CH 2 O), 28.3 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 2022.9841 (M + ); found 2024.0846 (M+H + ). 
 
     Example 2 
                         
 Synthesis of Compound 2: A clear solution of 5 (177 mg, 0.39 mmol) in 10 mL of THF was prepared, and a slurry of 10 (122 mg, 9.8×10 −5  mol) and DIPEA (0.17 mL, 1.00 mmol) was prepared in 20 mL of THF in a separate flask. Both solutions were cooled to 0° C., then combined. The mixture was warmed gradually to RT and stirred for 16 h, after which time the solvent was removed in vacuo. Purification was achieved using column chromatography on silica gel to afford the product as a white solid (gradient elution from 80:1 CH 2 Cl 2 :MeOH until no detectable 5 was observed as determined using UV spotting to 20:1 CH 2 Cl 2 :MeOH to obtain the desired product; R f =0.54 using 9:1 CH 2 Cl 2 :MeOH as the developing solvent). Yield: 227 mg (97%). The excess/unreacted 5 was also recovered from this purification (R f =0.76 using 9:1 CH 2 Cl 2 :MeOH as the developing solvent). Yield: 48 mg (99% of unreacted starting material based on recovered yield of hybrid polymer).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.25 (br, 3H, NH), 5.17 (br, 3H, NH), 5.09 (br, 3H, NH), 3.76 (br, 54H, CH 2 ), 3.62 (m, 30H, CH 2 ), 3.35 (br, 12H, CH 2 NHBoc), 2.20 (br, 3H, OH), 1.40 (s, 27H, C(CH 3 ) 3 ), 1.37 (s, 27H, C(CH 3 ) 3 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 169.4 (s, C 3 N 3 ), 166.3 (s, C 3 N 3 ), 165.7 (s, C 3 N 3 ), 165.4 (s, C 3 N 3 ), 165.2 (s, C 3 N 3 ), 164.1 (s, C 3 N 3 ), 156.2 (s, C(O)), 156.0 (s, C(O)), 79.3 (s, C(CH 3 ) 3 ), 72.2 (s, OCH 2 CH 2 OH), 70.1 (s, NHCH 2 CH 2 O), 61.7 (s, OCH 2 CH 2 OH), 47.9 (s, NCH 2 ), 47.4 (s, NCH 2 ), 43.5 and 43.1 (s, piperazine), 40.5 (s, NHCH 2 CH 2 O), 39.4 (s, CH 2 NHBoc), 39.1 (s, CH 2 NHBoc), 28.4 (s, C(CH 3 ) 3 ), 28.3 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 2374.2210 (M + ); found 2375.4347 (M+H + ). 
 
     Example 3 
                                           
 Synthesis of Compound 3: A clear solution of 6 (810 mg, 0.86 mmol) in 50 mL of THF was prepared, and a slurry of 10 (304 mg, 0.25 mmol) and DIPEA (0.4 mL, 2.35 mmol) was prepared in 50 mL of THF in a separate flask. Both solutions were cooled to 0° C., then combined. The mixture was warmed gradually to RT and stirred for 16 h, after which time the solvent was removed in vacuo. Purification was achieved using column chromatography on silica gel to afford the product as a white solid (20:1 CHCl 3 :MeOH; R f =0.33 using 10:1 CH 2 Cl 2 :MeOH as the developing solvent). Yield: 905 mg (96%).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.71 (br, 6H, NH), 5.59 (br, 6H, NH), 5.40 (br, 3H, NH), 5.23 (br, 3H, NH), 4.67 (d,  2 J H-H =12 Hz, 6H, amp-NCH 2 ), 3.79 (br, 54H, piperazine CH 2 , OCH 2 CH 2 OH), 3.58 (br, 42H, CH 2 , Boc-NCH 2 ), 3.30 (br, 30H, CH 2 NHBoc, amp-CH 2 ), 2.76 (pseudo t,  2 J H-H =12 Hz, 6H, amp-NCH 2 ), 1.75 (br d,  2 J H-H =12 Hz, 6H, amp-NCH 2 CH 2 ), 1.51 (m, 3H, amp-CH), 1.40 (s, 54H, C(CH 3 ) 3 ), 1.38 (s, 54H, C(CH 3 ) 3 ), 1.19 (m, 6H, amp-NCH 2 CH 2 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 169.0 (s, C 3 N 3 ), 166.2 (s, C 3 N 3 ), 165.9 (s, C 3 N 3 ), 165.8 (s, C 3 N 3 ), 165.3 (s, C 3 N 3 ), 165.1 (s, C 3 N 3 ), 164.5 (s, C 3 N 3 ), 164.2 (s, C 3 N 3 ), 156.1 (s, C(O)), 79.2 (s, C(CH 3 ) 3 ), 79.0 (s, C(CH 3 ) 3 ), 72.2 (s, OCH 2 CH 2 OH), 70.0 (s, NHCH 2 CH 2 O), 61.7 (s, OCH 2 CH 2 OH), 47.3 (s, Boc-NCH 2 ), 46.6 (s, Boc-NCH 2 ), 46.4 (s, amp-NCH 2 ), 43.0 (s, CH 2 , NHCH 2 CH 2 O and piperazine), 40.6 (s, amp-CH 2 ), 40.5 (s, CH 2 NHBoc), 38.3 (s, CH 2 NHBoc), 36.9 (s, amp-CH), 29.9, 29.7 (s, amp-NCH 2 CH 2 ), 28.5 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 3851.1728 (M + ); found 3852.4626 (M+H + ). 
 
     Example 4  
      Synthesis of Compound 5: A solution of cyanuric chloride (1.17 g, 6.36 mmol) in THF (200 mL) was cooled to 0C. A clear solution of HN(CH 2 CH 2 NHBOC) 2  (1.93 g, 6.36 mmol) in THF (20 mL) was added dropwise to the cyanuric chloride solution, followed by dropwise addition of a solution of DIPEA (1.3 mL, 7.63 mmol) in THF (20 mL). The solution was stirred at 0° C. for 1 h, then warmed gradually to RT and stirred for an additional 12 h. The solvent was removed in vacuo, and then the residue was taken up in CH 2 Cl 2  (100 mL). The solution was washed with water (3×150 mL), and then dried with MgSO 4 . Following filtration, the solvent was removed in vacuo. The product was obtained as a pure white solid by reprecipitation with hexanes from a clear solution of CH 2 Cl 2 . Yield: 2.79 g (97%).  1 H NMR (300 MHz, CDCl 3 ) δ: 4.95 (br, 2H, NH), 3.72 (m,  3 J H-H =6 Hz, 4H, NCH 2 ), 3.39 (t,  3 J H-H =6 Hz, 2H, CH 2 NHBoc), 3.37 (t,  3 J H-H =6 Hz, 2H, CH 2 NHBoc), 1.37 (s, 18H, C(CH 3 ) 3 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 169.9 (s, C 3 N 3 ), 165.6 (s, C 3 N 3 ), 156.0 (s, C(O)), 79.5 (s, C(CH 3 ) 3 ), 48.6 (s, NCH 2 ), 38.5 (s, CH 2 NHBoc), 28.2 (s, C(CH 3 ) 3 ). MS (ESI): calcd 450.1549 (M + ); found 451.1528 (M+H + ).  
     Example 5  
      Synthesis of Compound 6: A solution of cyanuric chloride (655 mg, 3.52 mmol) in THF (75 mL) was cooled to 0° C. A clear solution of 16 (2.825 g, 3.55 mmol) in THF (100 mL) was added to the cyanuric chloride solution, followed by addition of a solution of DIPEA (0.73 mL, 4.52 mmol) in THF (20 mL). The solution was stirred at 0° C. for 30 min, then warmed gradually to RT and stirred for an additional 12 h. The solvent was removed in vacuo, and then the residue was taken up in CH 2 Cl 2  (100 mL). The solution was washed with water (3×150 mL), and then dried with MgSO 4 . Following filtration, the solvent was removed in vacuo. Purification was achieved using column chromatography on silica gel (3:1 CH 2 Cl 2 :EtOAc; R f =0.08 using 10:1 CH 2 Cl 2 :EtOAc as the developing solvent) to afford the product as a white solid. Yield: 2.28 g (68%).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.62 (br, 2H, NH), 5.55 (br, 2H, NH), 4.69 (d, J H-H =11 Hz, 2H, amp-NCH 2 ), 3.63 (br, 4H, Boc-NCH 2 ), 3.56 (br, 4H, Boc-NCH 2 ), 3.40 (br, 2H, amp-CH 2 ), 3.30 (br, 8H, CH 2 NHBoc), 2.78 (pseudo t,  2 J H-H =11 Hz, 2H, amp-NCH 2 ), 1.70 (br d,  2 J H-H =13 Hz, 2H, amp-NCH 2 CH 2 ), 1.4 (m, 1H, buried under  t Bu proton peaks, amp-CH), 1.40 (s, 36H, C(CH 3 ) 3 ), 1.25 (m, 2H, amp-NCH 2 CH 2 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 169.6 (s, C 3 N 3 ), 166.0 (s, C 3 N 3 ), 165.8 (s, C 3 N 3 ), 164.2 (s, C 3 N 3 ), 156.1 (s, C(O)), 79.1 (s, C(CH 3 ) 3 ), 78.9 (s, C(CH 3 ) 3 ), 47.2 (s, Boc-NCH 2 ), 46.7 (s, Boc-NCH 2 ), 46.5 (s, amp-NCH 2 ), 42.9 (s, amp-CH 2 ), 40.5 (s, CH 2 NHBoc), 38.3 (s, CH 2 NHBoc), 36.3 (s, amp-CH), 29.5 (s, amp-NCH 2 CH 2 ), 28.4 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 942.4722 (M + ); found 943.5674 (M+H + ).  
     Example 6 
                         
 Synthesis of Compound 8: Both 7 (423 mg, 1.27 mmol) and 4 (1.27 g, 3.8 mmol) were dissolved separately in THF (100 mL each) to give a slurry and a clear solution, respectively. DIPEA (2.15 mL, 12.7 mmol) was added to the solution of 7, and then both solutions were cooled to 0° C. The two solutions were combined rapidly, and the slurry was stirred at 0° C. for 1 h. The solution was then warmed gradually to RT and stirred for an additional 15 h. The solvent was removed in vacuo. The residue was dissolved in CH 2 Cl 2  (100 mL), and this solution was washed with water (3×100 mL). The organic phase was dried with MgSO 4 , and following filtration, the solvent was removed in vacuo. Purification was achieved using column chromatography on silica gel (4:1 CH 2 Cl 2 :EtOAc; R f =0.13 using 10:1 CH 2 Cl 2 :EtOAc as the developing solvent) to afford the product as a white solid. Yield: 1.29 g (83%).  1 H NMR (300 MHz, CDCl 3 ) δ: 3.77 (br, 36H, CH 2 , piperazine), 3.41 (br, 12H, CH 2 NBoc), 1.42 (s, 27H, C(CH 3 ) 3 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 169.5 (s, C 3 N 3 ), 165.1 (s, C 3 N 3 ), 164.3 (s, C 3 N 3 ), 154.5 (s, C(O)), 80.1 (s, C(CH 3 ) 3 ), 43.2 (s, CH 2 ), 43.1 (s, CH 2 ), 42.9 (s, CH 2 NBoc), 42.6 (s, CH 2 NBoc), 28.2 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 1224.5367 (M + ); found 1225.7524 (M+H + ). 
 
     Example 7 
                         
 Synthesis of Compound 9: A clear solution of 8 (968 mg, 0.76 mmol), DIPEA (0.4 mL, 2.4 mmol) and H 2 NCH 2 CH 2 OCH 2 CH 2 OH (0.8 mL, 8.0 mmol) in THF (25 mL) was heated at 65° C. for 24 h, during which time a precipitate formed. The solvent was removed in vacuo. The residue was dissolved in CH 2 Cl 2  (100 mL), and this solution was washed with with water (3×150 mL). The organic phase was dried with MgSO 4 , and following filtration, the solvent was removed in vacuo to afford the product as a white solid (1.06 g, 97%).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.16 (br t, 3H, NH), 3.78 (br, 36H, CH 2 , piperazine), 3.72 (br, 6H, CH 2 ), 3.59 (br, 18H, CH 2 ), 3.42 (br, 12H, CH 2 NBoc), 2.87 (br t, 3H, OH), 1.46 (s, 27H, C(CH 3 ) 3 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 166.2 (s, C 3 N 3 ), 165.3 (s, C 3 N 3 ), 165.1 (s, C 3 N 3 ), 154.8 (s, C(O)), 79.9 (s, C(CH 3 ) 3 ), 72.3 (s, OCH 2 CH 2 OH), 70.1 (s, NHCH 2 CH 2 O), 61.6 (s, OCH 2 CH 2 OH), 43.0 and 42.9 (s, CH 2 CH 2 NBoc, piperazine), 40.4 (s, NHCH 2 CH 2 O), 28.4 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 1431.8436 (M + ); found 1432.9504 (M+H + ). 
 
     Example 8 
                         
 Synthesis of Compound 10: Concentrated aqueous HCl (20 mL) was added to a slurry of 9 (1.01 g, 0.71 mmol) in MeOH (40 mL). The solution grew clear, and was stirred at RT for 12 h. Alternatively, the solution could be heated at 50° C. for 3 h to decrease the reaction time. Following either of these protocols, the solution was concentrated in vacuo until only ca. 5 mL of water remained. The residue was diluted with 50 mL of water, and this solution was washed with CH 2 Cl 2  (3×100 mL). The solvent was removed from the aqueous layer in vacuo to afford the product as a white solid. Yield: 838 mg, 96% (calculated assuming 3 HCl salt). Note that to determine complete deprotection of the Boc groups on the precursor molecule occurred, MS analysis must be performed to ensure none of the possible by-products exist since they are not detectable in low amounts using  1 H or  13 C{ 1 H} NMR spectroscopy or TLC analysis.  1 H NMR (300 MHz, D 2 O) δ: 4.14 (br, 12H), 3.95 (br, 24H), 3.69 (br, 18H), 3.64 (br, 6H), 3.34 (br, 12H),  13 C{ 1 H} NMR (75.5 MHz, D 2 O) δ: 161.9 (s, C 3 N 3 ), 158.1 (s, C 3 N 3 ), 156.0 (s, C 3 N 3 ), 154.3 (s, C 3 N 3 ), 71.7 (s, OCH 2 CH 2 OH), 68.6 (s, NHCH 2 CH 2 O), 60.5 (s, OCH 2 CH 2 OH), 43.5 (br, CH 2 , piperazine), 43.1 (br, CH 2 , piperazine), 40.7 (br, CH 2 , piperazine), 40.3 (s, NHCH 2 CH 2 O). MS (MALDI): calcd 1131.6863 (M + ); found 1132.8062 (M+H + ). 
 
     Example 9  
      Synthesis of Compound 14: A solution of cyanuric chloride (649 mg, 3.52 mmol) in THF (75 mL) was cooled to 0° C. A clear solution of 13 (2.34 g, 7.70 mmol) in THF (100 mL) was added to the cyanuric chloride solution, followed by addition of a solution of DIPEA (1.8 mL, 10.6 mmol) in THF (20 mL). The solution was stirred at 0° C. for 30 min, then warmed gradually to RT and stirred for an additional 12 h. The solvent was removed in vacuo, and then the residue was taken up in CH 2 Cl 2  (100 mL). The solution was washed with water (3×150 mL), and then dried with MgSO 4 . Following filtration, the solvent was removed in vacuo. The product was obtained as a pure white solid by reprecipitation with hexanes from a clear solution of CH 2 Cl 2 . Yield: 2.52 g (99%).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.53 (br, 2H, NH), 5.15 (br, 2H, NH), 3.64 (t,  3 J H-H =6 Hz, 4H, NCH 2 ), 3.58 (t,  3 J H-H =6 Hz, 4H, NCH 2 ), 3.28 (m, 8H, CH 2 NHBoc), 1.40 (s, 18H, C(CH 3 ) 3 ), 1.38 (s, 18H, C(CH 3 ) 3 ).  13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ) δ: 168.7 (s, C 3 N 3 ), 165.1 (s, C 3 N 3 ), 156.1 (s, C(O)), 79.0 (s, C(CH 3 ) 3 ), 47.8 (s, NCH 2 ), 47.0 (s, NCH 2 ), 39.3 (s, CH 2 NHBoc), 37.4 (s, CH 2 NHBoc), 28.3 (s, C(CH 3 ) 3 ), 28.2 (s, C(CH 3 ) 3 ). MS (ESI): calcd 717.3940 (M + ); found 718.5813 (M+H + ).  
     Example 10 
                         
 Synthesis of Compound 15: Neat 4-aminomethylpiperidine (1 mL, 7 mmol) was added to a clear solution of 14 (849 mg, 1.18 mmol) in THF (80 mL). The solution was stirred at RT for 12 h. The solvent was removed in vacuo, and then the residue was taken up in CH 2 Cl 2  (100 mL). The solution was washed with water (3×150 mL), and then dried with MgSO 4 . Following filtration, the solvent was removed in vacuo to afford the product as a pure white foam. Yield: 940 mg (99%).  1 H NMR (300 MHz, CDCl 3 ) δ: 5.77 (br, 2H, NH), 5.53 (br, 2H, NH), 4.68 (d,  2 J H-H =13 Hz, 2H, amp-NCH 2 ), 3.64 (br, 4H, Boc-NCH 2 ), 3.55 (br, 4H, Boc-NCH 2 ), 3.30 (br, 8H, CH 2 NHBoc), 2.76 (pseudo t,  2 J H-H =13 Hz, 2H, amp-NCH 2 ), 2.57 (d,  3 J H-H =6 Hz, 2H, amp-CH 2 ), 1.76 (br d,  2 J H-H =11 Hz, 2H, amp-NCH 2 CH 2 ), 1.4 (m, 1H, buried under  1 Bu proton peaks, amp-CH), 1.40 (s, 18H, C(CH 3 ) 3 ), 1.38 (s, 18H, C(CH 3 ) 3 ), 1.11 (q of d,  2 J H-H =11 Hz,  3 J H-H =4 Hz, 2H, amp-NCH 2 CH 2 ).  13 C{ H} NMR (75.5 MHz, CDCl 3 ) δ: 165.8 (s, C 3 N 3 ), 164.0 (s, C 3 N 3 ), 156.1 (s, C(O)), 156.0 (s, C(O)), 78.8 (s, C(CH 3 ) 3 ), 78.6 (s, C(CH 3 ) 3 ), 47.7 (s, Boc-NCH 2 ), 47.0 (s, Boc-NCH 2 ), 46.2 (s, amp-NCH 2 ), 43.0 (s, amp-CH 2 ), 40.6 (s, CH 2 NHBoc), 39.7 (s, amp-CH), 38.1 (s, CH 2 NHBoc), 29.6 (s, amp-NCH 2 CH 2 ), 28.2 (s, C(CH 3 ) 3 ). MS (MALDI): calcd 795.5331 (M + ); found 796.5796 (M+H + ). 
 
     Example 11  
      The following synthetic scheme outlines an alternative means of synthesizing macromolecules of the present invention.  
                 
 
      All of the compositions and/or methods disclosed and claimed in this specification can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents which are both chemically and physiologically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.  
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