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The synthesis and characterization of 3-deoxycapsidiol (10), a possible intermediate in the biosynthesis of capsidiol. The syntheses of novel isomers of aristolochene and eremophilene together with comparative antifungal activity of the various capsidiol analogues.

Research has been conducted on C-phosphonate-based decaprenolphosphoarabinose analogues' panel. The synthesis of this panel has been carried out and the details are reported.

Research has been conducted on the streptothricine F, a peptidyl nucleoside antibiotic. The timing and formation of the arginine-derived base streptolidine's incorporation during streptothricine F biosynthesis have been investigated and the details are reported.

Research has been conducted on the zeaxanthin-producing bacterium Paracoccus species strain PTA-3335 cultures grown with the (super)13 C-labeled glucose supplement. Isolation of zeaxanthin has been carried out and the results indicate that zeaxanthin's isoprenoid precursors have been biosynthesized via the mevalonate pathway.

Research has been conducted on the recombinant expression of the ispC gene of Escherichia coli. Results indicate that this expression specifies 2C-methyl-D-erythritol 4-phosphate synthase in a form that can be purified by metal-chelating chromatography.

Research has been conducted on the yersiniose A, an immunodominant branched-chain sugar found in the O-antigen of Yersinia pseudotuberculosis VI. The isolation and characterization of the enzyme involved in the yersiniose A biosynthesis have been carried out and the results are reported.

Research has been conducted on the squalene isolated from shark liver oil. The biosynthesis of squalene and dihydrosqualene in cultures of Streptomyces sp. has been carried out via the methylerythritol phosphate pathway and the results are presented.

Research has been conducted on the acaterin, a secondary metabolite produced by Pseudomonas sp. A 92. The results of the feeding experiments with (super)2 H- and (super)13 C-labeled decanoic acid and octanoic acid demonstrate that acaterin is biosynthesized via coupling of C (sub)5 unit with octanoate.

An aminobenzo(b)fluorene called stealthin C was synthesized, isolated from a Streptomyces murayamaensis culture and incorporated into kinamycin D. It was found to be a new intermediate in the biosynthesis of the benzo(b)fluorene antibiotic after analysis of a deuterated sample showed it to be specifically incorporated into kinamycin D. It is also postulated to be the hydroxylation substrate for the biosynthesis of stealthin A by S. viridochromogenes.

The synthesis and characterization of a new composition of carbon and nitrogen only are described. The composition is prepared by thermolysis of 2-halo-4,5-dicyanoimidazole derivatives functionalized with -H and -I as leaving groups at the 1-position. The reaction proceeds with diaminomaleonitrile and following a few steps, yields Tris(imidazo)(1,2-a:1,2-c:1,2-e)-1,3,5-triazine-2,3,5,6,8,9-hexacarbonitrile of formula C15N12.

An efficacious, optimized two-step procedure for preparing 1,2,4-dithiazolidine-3,5-dione through the key intermediate 3-ethoxy-1,2,4-dithiazolin-5-one is described. It involves the conversion of 3-ethoxy-1,2,4-dithiazolin-5-one with concentrated aqueous hydrochloric acid upon short reflux to 1,2,4-dithiazolidine-3,5-dione and its desulfurization with various trivalent phosphorus compounds to produce O-ethyl cyanate and carbonyl sulfide. The reaction also allows entry to 3,5-diethoxy-1,2,4-thiadiazole.

The D-(-)-quinic acid (1) is converted to the fungal metabolites mycosporin I (2) and mycosporin-gly (13) which possess an absolute S configuration. The C5 hydroxyl substituent in 1 is oxidized in vivo to a keto group and at the C3 is attached to the aminoacid side chain of the mycosporin. The biosynthetic mechanism follows via iminophosphorane (64) which on aza-Wittig reaction with glyoxylate and reduction of the consecutive imine lead to a compound that results in 13 on deprotection. The coupled product between 64 and diethyl ketomalonate on reduction of ester groups produces 2.

X-ray crystallography facilitates the study of the marine antibiotic pentabromopseudilin structure. It reveals that the shikimate pathway, associated with P-hydroxybenzoic acid, is the source of the benzene ring. The phytotoxic antibiotic, which demonstrates antitumor activity, is superior to penicillin.

A study of the andrimids and moiramides A-C, which were isolated from solid agar cultures of a marine isolate of the bacterium Pseudomonas fluorescens, revealed that the acylsuccinimide fragment was derived from a combination of amino acid and acetate building blocks. The biosynthesis involved a dipeptide-like intermediate that was obtained from gamma-amino-beta keto acids.

Bis-ribosyl nucleotide of purity which is suited for spectral analysis and biochemical studies is prepared through a histidine biosynthesis intermediate using a plasmid DNA construct. The recombinant DNA plasmid which controls overexpression of proteins is an enriched source of the first three enzymes in the histidine biosynthetic process.

A study of the biosynthesis and stereochemistry of asukamycin reveals that asukamycin should be part of a set of compounds bearing the 4-OH and the oxirane oxygen on the same side of the cyclohexenone plane. It also confirmed a powerful shift effect and the 4S,5R, 6S configuration for the compound. Hydrogen at C-3 derives from a source besides the precursor, glycol. During the integration of the mC7N units, none of the hydroxymethyl hydrogen of glycol are present.

A common biosynthetic precursor serves as a channel for the production of varying neolignans and as chemical proof to Gottlieb's theory. An internal alkene is adequately activated to ensure its interaction with quinone methide. The Buchi quinone ketal cycloaddition is intricately examined by analyzing quinone methide. Bicyclooctaroid natural product is prepared to help the examination. This led to the accurate synthesis of spiro undecanes in high quantities.

Cyclobutenediones containing acyl substitutents were synthesized. Results showed that 4-heteroalkyl-3-(tri-n-butylstannyl)-3-cyclobutene-1,2-diones 4-methyl-3-(tri-n-butylstannyl)-3-cyclobutene-1,2-dione were involved in palladium-copper-cocatalyzed cross-coupling with acyl halides and in carbonylative cross-coupling with aryl or heteroaryl iodides. The resulting 3-acyl-3-cyclobutenediones and cyclobutenedione monoacetals can be used to extend the synthetic potential of cyclobutenediones in organic synthesis.

NMR and X-ray analyses establish the absolute configuration of terpestacin, a sesterterpene isolated from Arthrinium sp. and shown to inhibit the HIV-mediated formation of syncytium. The study reveals that terpestacin, which is marked by a bicyclo(13.3.0)octadecatetraenyl ring, possesses a configuration at C1 and C5 different from that of its close cousins, retigenaric acid and variculanol. Its biosynthetic route is also traced by incorporation of (13C)acetates into its structure.

Research has been conducted on beta-carotene synthesis. Isolation of two allylic halide units by a sulfur atom to provide the system stability is described.

A study concerning the synthesis of acetylenic and diacetylenic dipyrrole dialdehydes from the pyrrole starting material is presented. Results indicate the importance of the synthetic route for the dipyrrole dialdehydes synthesis.

The stereochemical course of the pheromone biosynthesis is addressed by using female gametes of the marine brown alga Ectocarpus siliculosus and chiral deuterium-labeled arachidonic acids. The biosynthetic sequence has proceeded via intermediary 9-hydroperoxyrachidonic acid, which is cleaved with loss of the C(16)-[H.sub.8] into the [C.sub.11]-hydrocarbon dictyoterene C and 9-oxonona-(5Z,7E)-dienoic acid.

An efficient total synthesis of notoamide J, a new prenylated indole alkaloid and potential biosynthetic precursor is presented. The synthesis starting from L-proline and a substituted tryptophan derivative employs an oxidation and pinacol rearrangement for the formation of the oxindole in the final step.

Mild and facile preparations of 2-substituted or 2,3-disubstituted indole compounds are achieved by RhH(CO)[([Ph.sub.3]P).sub.3]-catalyzed reaction of N-propargylanilines in hexafluoroisopropyl alcohol (HFIP). The formation of indoles is derived from an o-allenylaniline intermediate, which is generated by the Rh(I)-catalyzed amino-Claisen rearrangement of N-propargylanilines.

The reactivity of porphyryl acrylates and their homologues is analyzed and a new synthetic approach is developed for the multifunctional porphyrins by using [alpha],[beta]-unsaturated acyl porphyrins. This method has given regioselectively access to either a rearrangement product or the product of esterification reactions, depending on the reaction conditions.

Nickel-chelating lipids are prepared for use as functionalized templates for 2-D crystallization of membrane proteins. Alkylations of fluorinated alcohols has proceeded with the application of prolonged sonication and the formation of 2-D crystals of the His-tagged membrane protein BmrA from Bacillus subtilis is described.

The stereoselective acetylation of meso-2,2-dimethyl-1,3-cyclohexanediol by vinyl acetate in the presence of three lipases has given the (1R,3S)-monoester in high enantiomeric excess. Optically active monoacetates are converted to both enantiomers of 3-hydroxy-2,2-dimethylcyclohexanone, a versatile chiral building block.

The samples of [K.sub.3]P[O.sub.4] from different suppliers are examined by various methods, which have disclosed that the use of pure and anhydrous [K.sub.3]P[O.sub.4] has provided higher ynamide yields in comparison to samples contaminated with hydrates. The studies have shown that ynamides can undergo regioselective hydroamination with carbamates.

Highly convergent syntheses of eight phorboxazole congeners and their evaluation against a diverse panel of human solid tumor cancer cell lines are described. (+)-C(46)-chlorophorboxazole A has displayed picomolar (pM) inhibitory activity in many cell lines.

The article explains the effective and stereoselective dimerization of various pyrroloindolizine derivatives. The approach has also been found to be extremely useful for the biosynthesis of complex myrmicarin alkaloids.

The properties, configuration and the first total synthesis of the antitumor natural product, (+) and (-)-pericosine A is being described. The synthesis process has been proved to be extremely useful, as it gives excellent stereoselectivity.

A very efficient method for the synthesis of a natural oligosaccharide antibiotic active against Helicobacter pylori is being discussed. The technique gives a complete chemoselective activation of the bromo sugar in presence of the thioglycoside acceptor.

The synthesis, purification and spectral properties of new dithienothiophene-based fluorescent dyes with a terminal alkyl bromide group are presented. The bromides are converted to isothiocyanates and N-succinimidyl esters and the new fluorophores have displayed intense fluorescence emission and high photostability.

The investigation of incorporation of [[super 13][C.sub.2]]acetate moieties of furanonaphtho-quinone I(FNQ I) and endophenazine A is presented.

The new spiro[4.5]acetal okaspirodiol was isolated from Streptomyces sp. Go TS 19 as a secondary metabolite in yields up o 380 mg/L. The biosynthesis of spiro[4.5]acetal okaspirodiol was investigated by feeding experiments with [.sup.13.C]-labeled precursors proving its origin from a new type of the rare mixed acetate-glycerol biosynthetic pathway.

Seven depsipeptides, named largamides A-G, and one cyclic peptide, largamide H, are isolated from the marine cyanobacterium Oscillatoria sp.. The largamides from the single homogeneous collection of the Oscillatoria sp. are classified into three different classes according to their structural features, providing an example of the remarkable biosynthetic capabilities of cyanobacteria.

The completion of a total synthesis of 7,11-epi-thyrsiferol is described and the antimitotic activities of thyrsiferol, [DELTA.sup.15.28]-dehydrothyrsiferol, and 7,11-epi-thyrsiferol are compared. The synergistic behavior of the title compound and colchicine to inhibit cell proliferation is evaluated and the results of conformational searches that provide additional insight concerning the SAR profile of the thyrsifol family of natural products are described.

A four step method of enzymatic coupling catalyzed by the Ce17BE197A glycosynthase from Humicola insolens was used to synthesize complex oligosaccharides containing alpha-D-xylosyl-(1->6)-beta-D-glucosyl residues and unsubstituted beta-(1->4)-linked D-glucosyl units. The complex olygosaccharides were found to be useful in mapping the active site of a key enzyme in plant cell wall biosynthesis and modification.

Amphilectosins A and B are identified from the organic extract of Pseudopterogorgia elisabethae collected in the Florida Keys, along with seco-pseudopterosins and pseudopterosins. The structure of the amphilectosins, C-12-C-13 dehydro seco-pseudopterosins, suggested that these metabolites provide the biosynthesis link between the seco-pseudopterosins and pseudopterosins.

Novel thioiso pyrimidine and purine nucleosides substituted with exocyclic methylane is synthesized starting from D-xylene. The glycosyl donor was synthesized from D-xylose, using cyclization of dimensylate with sodium sulfide as a key step.

Research has been conducted on isoprenoid biosynthesis. Results demonstrate that this biosynthesis is important for the analysis of Streptomyces diterpene cyclase's reaction mechanism.

Research has been conducted on amphidinolide X, a cytotoxic 16-membered macrodiolide from marine dinoflagellate Amphidinium sp. The authors describe the isolation, structure elucidation and biosynthesis of amphidinolide X.

Research has been conducted on antitumor agent GKK1032A (sub)2. The author has investigated this agent by means of administration of isotopically labeled precursors to Penicillium sp. GKK1032, and has demonstrated that GKK1032A (sub)2 backbone consists of L-tyrosine and a nonaketide chain.

Research has been conducted on pyridoxamine C (sub)3 unit. The authors report that biosynthetic origin of this unit has been investigated in yeasts, and that the three-carbon pyridoxamine C-6,5,5' unit has been produced by triose.

Research has been conducted on intramolecular Diels-Alder reactions of 2-azadiene models. The authors report the results of quantum chemical studies of these models carried out in investigating stereochemical features of the cyclization involved in paraherquamide A biosynthesis.

Research has been conducted on vitamin B (sub)12 biosynthesis. The author presents the chronology of discoveries along the biosynthesis pathways including aerobic and anaerobic pathways to B (sub)12.

Research has been conducted on enantiomeric sesquiterpenes from marine nudibranch Doriopsilla areolata. The authors describe biogenesis of these compounds examined via feeding of glucose and acetate, and demonstrate that the compounds' origin can be supported via mevalonic acid.

Research has been conducted on poisoning toxins DTX-5a and DTX-5b. The biosynthetic origins of these toxins have been investigated via suplementing cultures of dinoflagellate Prorocentrum maculosum with stable isotope labeled precursors, the results are presented.

Research has been conducted on (+/-)-Linderol A. The results of the total synthesis of this hexahydrodibenzofuran constituent of Lindera umbellata bark are described.

Research has been conducted on amino acid 4-methylproline. The authors report that the biosynthesis of this compound from cyanobacteria's Nostoc genus has been studied both on enzymatic and genetic levels.