Structurally Diverse Macrolactams from an Antarctic Streptomyces Species.

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.