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The direct conversion of -hydroxyproline derivatives into 5-hydroxypyrazin-2(1H)-ones under Mitsunobu conditions has been discovered to be a general biomimetic protocol generating IMDA intermediates and has been applied to the concise, biomimetic total syntheses of d,l-stephacidin A and d,l-brevianamide B. [ABSTRACT FROM AUTHOR]

Covering: up to 2009 [ABSTRACT FROM AUTHOR]

Antipodal (−)-versicolamide B and notoamides L−N were isolated from a marine-derived Aspergillussp. The possible biosynthetic pathway of enantiomeric pairs of notoamide B and versicolamide B are proposed. Notoamide L is the first metabolite containing 25 carbons in the related prenylated indole alkaloids. Notoamide M is potentially a precursor to the proposed azadiene species involved in the putative intramolecular Diels−Alder reaction in the biogenesis of the bicyclo[2.2.2]diazaoctane ring system. [ABSTRACT FROM AUTHOR]

Fourteen analogs of the marine natural product largazole have been prepared and assayed against histone deacetylases (HDACs) 1, 2, 3, and 6. Olefin cross-metathesis was used to efficiently access six variants of the side-chain zinc-binding domain, while adaptation of our previously reported modular synthesis allowed probing of the macrocyclic cap group. [ABSTRACT FROM AUTHOR]

Beyond the identification of 3-amino-5-hydroxybenzoic acid (AHBA) and d-glucosamine as biosynthetic precursors to mitomycin C (5) and FR900482 (6), little is known about the pathway Nature uses to prepare these antitumor antibiotics. To gain some insight into their biosynthesis, amino acids 1and 2as well as C-2 N-acetylated derivatives 3and 4were prepared. Preparation of these putative biosynthetic intermediates and N-acetylcysteamine thioester analogues 28and 29should enable confirmation of their involvement in FR900482 and mitomycin C biosynthesis. [ABSTRACT FROM AUTHOR]

An advanced metabolite, named premalbrancheamide, involved in the biosynthesis of malbrancheamide ( 1) and malbrancheamide B ( 2) has been synthesized in double 13C-labeled form and was incorporated into the indole alkaloid 2by Malbranchea aurantiaca. In addition, premalbrancheamide has been detected as a natural metabolite in cultures of M. aurantiaca.The biosynthetic implications of these experiments are discussed. [ABSTRACT FROM AUTHOR]