The Crocacins, Novel Antifungal and Cytotoxic Antibiotics from Chondromyces crocatus and Chondromyces pediculatus (Myxobacteria): Isolation and Structure Elucidation

• Published in: European journal of organic chemistry Vol. 1999; no. 5; pp. 1085 - 1089
• Main Authors: Jansen, Rolf, Washausen, Peter, Kunze, Brigitte, Reichenbach, Hans, Höfle, Gerhard
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag GmbH 01.05.1999; WILEY‐VCH Verlag GmbH
• Subjects: Antibiotics; Chondromycesspec; Fungicides; Myxobacteria; Relative configuration; Structure elucidation
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/(SICI)1099-0690(199905)1999:5<1085::AID-EJOC1085>3.0.CO;2-G

Four novel antifungal and highly cytotoxic metabolites, the crocacins A–D (1–4), were isolated in our screening of the myxobacterial genus Chondromyces from strains of C. crocatus and C. pediculatus. Crocacin A, B, and D (1, 2, and 4) are unusual dipeptides of glycine and a 6‐aminohexenoic or ‐hexadienoic acid, which is N‐protected by a complex polyketide‐derived acyl residue. The latter is a multiply substituted phenylundecatrienoic acid, which is found as its primary amide crocacin C (3). Based on 1H coupling constants, NOEs and MM+ calculations the relative configuration of the asymmetric centers and their preferred conformation are proposed for the crocacins.