Structurally Diverse Macrolactams from an Antarctic Streptomyces Species

Abstract

Twelve new polyenic macrolactams, cyclamenols G−R (1 and 3−13), together with the known analogue cyclamenol A (2), were isolated from Streptomyces sp. OUCMDZ-4348. Their structures were elucidated by spectroscopic analysis, quantum chemical calculations, chemical derivatizations, and Mosher's methods. The sequenced genome of OUCMDZ-4348 revealed the putative biosynthetic gene cluster of cyclamenols. It was proposed that the polycyclic natural products, cyclamenols H−R, might be formed from cyclamenols A and G through nonenzymatic intramolecular cycloadditions and oxidative cyclizations.