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Inhibitory properties of Escherichia coli Tfase have been determined by means of crystal structure study of Escherichia coli GAR Tfase. The presence of the hydrated aldehyde has been confirned in solution by (super)13 C - (super)1 H NMR spectroscopy.

Research is presented demonstrating the absolute configuration and quinoxapeptin relative of the synthesis of quinoxapeptin A-C and luzopeptin A-C, C2-symmetric cyclic depsidecapeptides which have two pendant heterocyclic chromophores.

The diastereoselective total synthesis of the vancomycin aglycon is described. Vancomycin is a glycopeptide antibiotic used to treat resistant bacterial infections or for treating patients who are allergic to beta-lactam antibiotics.

Convergent solution-phase combinatorial synthesis is discussed relative to increasing diversity via rigid biaryl and diarylacetylene couplings. Solution-phase synthesis of iminodiacetic acid diamide libraries linked to aryl iodides and palladium-catalyzed dimerization has been studied. Mixtures with 64,980 components have been produced in four steps from N-BOC-iminodiacetic acid anhydride and 21 starting materials that are readily available. Sequential Stille couplings and biaryl formation are used in the synthesis.

Solvolysis pH-rate profiles of two reactive CC-1065/duocarmycin alkylation subunit analogues, N-BOC-CBQ and N-BOC-CNA, shows a reactivity ranging from pH 2 to 12. The study also demonstrated a progressively diminished vinylogous amide conjugation that leads to a corresponding increase in reactivity to conformations proposed by the DNA-bound CC1065. The results indicate that the observed CC-1065 and duocarmycin DNA alkylation reaction at pH 7.4 is not an acid-catalyzed reaction.

Analogue 7 of the duocarmycins and CC-1065 manifested increased solvolysis reactivity at pH 3. Theincrease, which is consistent with the increased electron-withdrawing properties and conjugation of thioamides relative to amides, can be attributed to a diminished vinylogous amide stabilization of the reacting alkylation subunit. Amidine 6, which underwent preferential N2 amidine linkage hydrolysis, was found to be more unstable than 7 despite the diminished electron-withdrawing properties.

Synthesis of the cyclic heptadepsipeptide HUN-7293 may be efficiently carried out through the adoption of an approach that makes use of the macrocyclization concept. Such a method leads to the formation of a requisite linear depsipeptide characterized by intramolecular H-bonding preorganization of the acyclic substrate. Another viable approach for facilitating the synthesis of cyclic compounds requires the introduction of a D-DGCN subunit to the L-amino acid precursor. The latter approach, however, has been found to generate suboptimal results compared to the former.

Research was conducted to examine the mechanism for catalysis of DNA alkylation by the potent antitumor antibiotic duocarmycin SA (DSA) by determining the structure of a DNA adduct of the indole analogue lackig three methoxy functional groups. 1H NMR spectroscopy was used to determine the three-dimensional structure of DSA-indole covalently bound to the 11 base pair 'AATTA' DNA duplex. Results provide the most direct proof of the hypothesis that the binding of the ligand in the DNA minor groove plays an important role in controlling DNA alkylation reactivity.

A study was conducted to analyze an approach to the solution phase preparation of biaryl libraries from iodoarenes. Pd-C was utilized as a readily available supported catalyst. The isolation and purification of small library mixtures were discussed. Results indicated that the direct convergent solution phase dimerization of combinatorially assembled iodoarene building blocks supports an effective and rapid pathway to symmetrical and unsymmetrical structures.

The concise total synthesis of phomazarin, the most well known and extensively analyzed aza anthraquinone, is described. The synthesis clearly established the structure for phomazarin based on the implementation of a heteroaromatic azadiene Diels-Alder reaction. The phomazarin C-ring was prepared via (4+2) cycloaddition of triethyl 1,2,4-triazone-3,5,6-tricarboxylate with trimethoxyethylene, followed by conversion of the cycloadduct to the cyclic anhydride. The fully functionalized phomazarin skeleton was achieved by linkage of the A- and C-rings via selective nucleophilic addition of the aryllithium reagent to the least restricted anhydride carbonyl of the cyclic anhydride and Friedel-Crafts closure of the B-ring.

The anti-tumorigenic action of marine natural products ignited medical interest on these products. Synthetic analyses of marine products ningalin A, lamellarin O, lukianol A and permethyl storniamide A and their analogues were performed. The products were analyzed under heteroaromatic azadiene Diels-Alder reactions. Micromolar cytotoxic activity against wild-type and multi-drug resistant (MDR) tumor cell lines were exhibited by Lamellarin O. Moreover, permethyl storniamide A reversed the MDR tumor cells.

An analogue of CC-1065, CBI-TMI and the duocarmycins was synthesized and analyzed in an experiment in which the amide linking the DNA binding and alkylation subunits has been replaced by a methylene. Experimental results showed that the analogue is remarkably stable to acid-catalyzed solvolysis consistent with alkylation subunit stabilization generated from a fully engaged vinylogous amide. The analogue, however, is unable to alkylate DNA even under extraordinary conditions. The findings underscore the critical role of the linking N2 amide in CC-1065 and the duocarmycins.

A carbocyclic C-ring analogue of the alkylation subunits of CC-1065 and duocarmycins, 1,2,9,9a-tetrahydro-1H-cyclopropa(C)benz(e)inden-4-one, was synthesized, a key step of which was implementation of the intramolecular Heck reaction. Results of an examination of its solvolysis reactivity, regioselectivity and mechanism showed that reactivity increased by 3,200 times with the removal of the nitrogen and resulting vinylogous amide stabilization, while reversing the inherent regioselectivity. However, it left the S(sub N)2 reaction mechanism unaltered.

Experiments were performed to illustrate the L-threonine side chain in bleomycin A2, a major component of the clinical antitumor drug Blenoxane. The studies provided evidences of a stable input of the L-threonine subunit on the 5'-GC,5'-GT cleavage selectivity in deglycobleomycin. The findings suggest the active role of the L-threonine side chain in promoting the preorganization of bleomycin A2 that facilitates successful DNA cleavage.

Experiments were performed to characterize the deglycobleomycin A2 analogs and to understand the mechanics of the valerate linker region. The findings suggest the significant contribution of the valerate subunit to DNA cleavage efficiency but has a minimal effect on the main 5'-GPy cleavage selectivity. However, the presence of a C3-hydroxy group proved the participation of the valerate subunit in an intermolecular H bond with nonbridging oxygen of a phosphate that enhances the binding affinity of a DNA-bound agent.

The structurally complex vancomycin is a member of a class of clinically important glycopeptide antibiotics used to treat methicillin-resistant Staphylococcus aureus and enterococci and bacterial infections in patients allergic to beta-lactam antibiotics. Studies were conducted to investigate the thermal atropisomerism of a series of vancomycin aglycons that define its scope, limitations and potential competitive reactions. The results are discussed.

Experiments were performed to investigate drug receptor activation through dimerization using multistep solution-phase combinatorial chemistry. Analyses of the data revealed the usefulness of solution-phase mixture synthesis and deconvolution protocols for large compound libraries and their applicability to linear and convergent syntheses. The complementation of the scanning and deletion deconvolution protocols makes them a dependable method for lead identification in large mixture libraries.

Oleamide is an endogenous fatty acid primary amide that possesses sleep-inducing properties in animals and that has been shown to effect serotonergic receptor responses and block gap junction communication. Herein, the potentiation of the 5-H[T.sub.1A] receptor response is disclosed, and a study of the structural features of oleamide required for potentiation of the 5-H[T.sub.2A] and 5-H[T.sub.1A] response to serotonin (5-HT) is described. Of the naturally occurring fatty acids, the primary amide of oleic acid (oleamide) is the most effective at potentiating the 5-H[T.sub.2A] receptor response. The structural features required for activity were found to be highly selective. The presence, position, and stereochemistry of the [[Delta].sup.9]-cis double bond is required, and even subtle structural variations reduce or eliminate activity. Secondary or tertiary amides may replace the primary amide but follow a well defined relationship requiring small amide substituents, suggesting that the carboxamide serves as a hydrogen bond acceptor but not donor. Alternative modifications at the carboxamide as well as modifications of the methyl terminus or the hydrocarbon region spanning the carboxamide and double bond typically eliminate activity. A less extensive study of the 5-H[T.sub.1A] potentiation revealed that it is more tolerant and accommodates a wider range of structural modifications. An interesting set of analogs was identified that inhibit rather than potentiate the 5-H[T.sub.2A], but not the 5-H[T.sub.1A], receptor response, further suggesting that such analogs may permit the selective modulation of serotonin receptor subtypes and even have opposing effects on the different subtypes.

A study was conducted on the hydroperoxide form of cobalt deglycoBleomycin A2 (HOO-CodGBLM) and its complex with oligonucleotide d(CCAGGCCTGG). The similarities in model structures between HOO-CoBLM and its corresponding aglycon, and the lack of a carbamoyl amino group as a potential axial ligand in the latter, suggest that the primary amine of Beta-aminoalanine is a ligand in the parent compound. The results also indicate that deglycoBLM analogues can serve as a good model to analyze the ds cleavage process.

The detailed concise total syntheses of nothapodytine B and (-)-mappicine are presented. Room-temperature, inverse electron demand Diels-Alder reaction of the N-sulfonyl-1-aza-1,1,3-butadiene for the introduction of the pyridone D ring with assemblage of a pyridone D ring precursor central to the structure were implemented. The concise and efficient total syntheses of nothapodytine B and (-)-mappicine was accomplished which suggests straightforward extensions to camptothecin and related analogues.

A novel and alternative synthetic approach was used to prepare and analyze derivatives of bleomycin A2 and deglycobleomycin A2 and their unnatural epimers for an evaluation of the role of their pyrimidine C4 amine group. A significantly reduced DNA cleavage efficiency was observed in the agent bearing a pyrimidine C4 dimethylamino substituent, while the agent where the pyrimidine C4 amino group was removed showed an even greater dimunition in DNA cleavage efficiency.

The synthesis and evaluation of CC-2065 and duocarmycin analogues incorporating the iso-Cl and iso-CBl alkylation subunits are described. The method was founded on a directed ortho metalation of an appropriately functionalized benzene or naphthalene precursor to regiospecifically install iodine at the C-2 position. Agents were observed to exhibit potent cytotoxic activity that correlates with their inherent reactivity which is consistent with previous studies.

A novel method of synthesizing a seven-membered C-ring analog (CNA) of the alkylation subunits of CC-1065 and the duocarmycins was designed through implementation of an alternative intramolecular Heck reaction. The procedure featured the use of palladium acetate as catalyst and 1,3-dihydronaphthalene as the starting material. It was indicated that the ground state destabilization fo the substrate activated the reagent for a rate determining SN2 nucleophilic addition.

The synthesis of fully substituted vancomycin with two 16-membered biaryl ether ring systmes (CD and DE) was reported. A potential solution to the control of the atropisomer stereochemistry was also proposed. It was observed that closure to form the CD ring system provided a 1:1 mixture of atropisomers, while closure of the DE ring system showed a slight preference for the natural atropisomer.

The origin of the DNA alkylation selectivity was evaluated through analysis of the reversed and sandwiched analogs of duocarmycin SA. Studies suggested that the ground state destabilization of the substrate disrupted the amide stabilization of the alkylation subunit and increased its reactivity toward nucleophiles. The DNA adenine-thymine minor grove binding mediates the reaction.

The synthesis and evaluation of shortened, simplified, and extended analogs of duocarmycin SA were described. Through x-ray structural and solvolysis regioselectivity studies. Results have shown that solvolysis preferentially occurred with cleavage of the C7b-C8 bond with the addition of a nucleophile to the least-substituted C8 cyclopropane carbon. The critical feature surrounding the regioselectivity was the degree of alignment of the two cyclopropane bonds available for cleavage.

Synthetic approaches to the natural duocarmycins and CC-1065 products have been developed through a wide range of studies, with the nature of DNA alkylation reaction determined in part by the agents identified from studies of analogs containing deep structural changes. These studies also identify relationships between biological activity, chemical reactivity and structure, the DNA alkylation reaction catalysis source, and the source of DNA alkylation selectivity. The efficacy and potency of the analogs could be better than those of the natural products. Additional analogs could still potentially be developed.

The characteristics of intramolecular nucleophilic aromatic substitution reactions were analyzed during the synthesis of (9R, 12S)- and (9S, 12S)-cycloisodityrosine and their N-methyl derivatives. The benzylic bromination of 2-fluoro-4-methylnitrobenzene by 1,3-dibromo-5,5,-dimethylhydantoin led to the synthesis of (S)- and (R)-3-fluoro-4-nitrophenylalanine methyl ester. Furthermore, 14-membered ring macrocyclization reactions led to formation of a biaryl ether by smooth 14-membered ring closure.

The relative and absolute chemistry of the potent antitumor antibiotic fostriecin have been determined. The results showed an absolute chemistry of 5R, 8R, 9R, 11R. A syn-diol stereochemical relationship between C8 and C9 and an anti-diol stereochemical relationship between C9 and C11 were established by 2D 1H-1H NMR NOE spectroscopy.

(+)-Duocarmycin A, epi-(+)-duocarmycin A and their unnatural enantiomers have been subjected to enantioselective total synthesis. A solution to the regulation of the relative and absolute stereochemistry of the remote stereocenters is given. A Dieckmann-like reaction facilitates the introduction of either the natural 6(R) or epi-6(S) stereochemistry via enantiomeric auxiliaries or the reaction of a specific auxiliary under thermodynamic conditions.

The enzyme oleamide hydrolase is responsible for the inactivation of neuromodulatory fatty acid amides, bioactive signalling molecules. The protein sequence of the fatty-acid amide hydrolase (FAAH) has similarities with the protein sequence of the various amidase enzyme sequences taken from divergent organisms. These different amidases share a common identifying sequence. The FAAH cDNA transfected COS-7 cells show high activity levels of oleamide hydrolase.

A difluoro substituted cyclopropane analog of the alkylation subunits of the parent members of a class of potent antitumor antibiotics is synthesized. The analog is the first of its kind to contain substitution or functionalization of the reactive center in the natural products. Showing increased reactivity, the analog is found to be less cytotoxic than other duocarmycin derivatives.

The synthesis of 7-cyano-1,2,9,9a-tetrahydrocyclopropa(c)benz(e)indol-4-one, (CCBI) helps to establish the electronic effect on functional reactivity of an agent. The nitrile substituent at C7 in N-BOC-CCBI has a small electronic effect on functional reactivity according to Hammett quantization. The mechanism involves rapid proton exchange and nucleophilic addition to least hindered carbon in cyclopropane is the rate determining step. Likewise, the positioning of nucleophile adenine N3 is the rate determining step in DNA alkylation, which does not affect DNA alkylation selectivity.

The enzyme oleamide hydrolase is responsible for the hydrolysis of oleamide, a sleep-inducing inducing lipid also known as cis-9-octadecenamide. A series of potent transition-state mimetic and mechanism-based inhibitors for the enzyme is developed and evaluated to determine the role of oleamide as a new biological signaling agent and oleamide hydrolase as a factor in its regulation.

The Sharpless asymmetric dihydroxylation of a substituted styrene produces derivatives of (R)-(3,4,5-trihydroxyphenyl)glycine. The formation of styrene involves methylation of 3,4,5-trihydroxybenzoate, formation of an aldehyde and a Wittig reaction. The oxidation of the styrene primary alcohol yields the derivative. CBZ deprotection, or CBZ deprotection and N-BOC protection of the free amino acid of the derivative yields other derivatives. (R)-(3,4,5-trihydroxyphenyl)glycine is present in the bicyclic ring of glycopeptide antibiotics such as vancomycin.

A rapid and multistep method for generating combinatorial chemical libraries is introduced. The procedure involves solution-phase parallel synthesis of high purity and multi-milligram quantities of chemical compounds for screening applications. It also includes liquid-liquid or liquid-solid extraction at each step to purify intermediates and final products through the elimination of reactants, unreacted precursors, reagents and byproducts.

The synthesis and characterization of 7-methoxy-1,2,9,9a-tetrahydrocyclopropa(c)benz(e)indole-4-one (MCB) are described. The core structure of the MCBI alkylation unit has been formed via modified Stobbe condensation/Friedel-Crafts acylation to generate the functionalized naphthalene precursors. Subsequent 5-exo-trig aryl radical-alkene cyclization completes the preparation of the 1,2-dihydro-3H-benz(ene)indole skeleton and final Ar-3' alkylation to introduce the cyclopropane. The reaction mechanism for the synthesis is outlined.

The key elements of the approach to the total synthesis of the potent antitumor antibiotic (-)-sandramycin are discussed. The synthesis of this naturally occurring agent involved a series of coupling reactions including the late stage introduction of the heteroaromatic chromaphore, symmetrical pentadepsipeptide coupling and 32-membered macrocylization. This approach is expected to provide insight on the utilization of cyclic decapepsipeptides in antitumor research.

The physiological role of an endogenous sleep-inducing lipid, cis-9-octadecenamide (oleamide), in sleep induction was determined by examining the synthesis and structure of C18H35NO, a chemical agent that accumulates in the cerebrospinal fluid of sleep-deprived cats. Previous studies have found this agent to increase in concentrations with sleep deprivation and to decrease upon recovery sleep. Tandem electrospray mass spectrometry revealed two primary fragments consistent with a long-chain alkane and nitrogen substituent capable of fragmenting as ammonia. High-performance liquid chromatography identified a molecular weight of 281.

The preparation of grandirubrine, imerubrine and isoimerubrine proceeds via the intermediate granditropone. The (4 + 2) cycloaddition between alpha-pyrone and cyclopropenone ketal involves the synthesis of grandirubrine. Granditropone undergoes regioselective hydroxylation to form grandirubrine. Imerubrine and isoimerubrine are produced by the O-methylation of grandirubrine.

The synthesis of the two enantiomers of antitumor-antibiotic fredericamycin A involves the inverse electron demand Diels-Alder reaction, Michael addition-intramolecular acylation, regiospecific benzannulation reaction and simple aldol closing. The natural and ent-fredericamycin A are obtained by the resolution of the penultimate precursor and its deprotection. A N-sulfonyl-1-aza-1,3-butadiene undergoes the inverse electron demand Diels-Alder reaction.

The adenine N3 alkylation is mediated by additional characteristics that resemble the imposed stereoelectronic control. Reactive 2,3,10,10a-tetrahydrocyclopropa(d)benzo(f)quinol-5-one (CBQ)-based agents alkylate same sites as the corresponding DSA-, CPI-, DA-, and CI-based agents. These agents have less selectivity among the established alkylation sites and low efficiency to alkylate DNA. Adducts obtained from adenine N3 addition to the least substituted cyclopropane carbon were detected under the relevant conditions of limiting agent.

The N(super 15)-methyl group plays a major role in the induction and maintenance of the conformational properties of the N-desmethyl derivatives of deoxybouvardin, RA-VII and are responsible for their adoption of the inherently disfavored C(super 30)-N(super 15) cis amide. The removal of the methyl group results in the exclusive adoption of the single biologically active conformation. The N(super 29)-methyl group is not essential for the adoption of C(super 30)-N(super 29) cis amide and does not change the conformational and biological properties of desmethyl derivatives.

The addition of one equivalent weight amount of lithium chloride into the cyclic peptide RA-VII solution changes the conformations and conditional equilibria while excess addition of lithium chloride do not produce any further effect. Lithium chloride forms a complex conformation which resembles the X-ray structure conformation. The lithium chloride complex produces a perturbation in the relative orientations of the two aromatic rings of the characteristic biaryl ether ring system by weakening the transannular hydrogen bonds.