Acremonidins, New Polyketide-Derived Antibiotics Produced by Acremonium sp., LL-Cyan 416.

Acremonidins A-E (1-5) were produced by fermentation of Acremonium sp., LL-Cyan 416, in heterogeneous phases. The structures of these compounds, containing a bridging keto group, were determined by spectroscopic analysis. Acremonidins A and B showed moderate activity against Gram-positive bacteria, including the methicillin-resistant staphylococci and vancomycin-resistant enterococci. Selective acylations of acremonidin B afforded ester derivatives 6-9 that exhibited improved antibacterial activity.