Ravenic acid, a new tetramic acid isolated from a cultured microfungus, Penicillium sp.

A new antibiotic polyene tetramic acid, ravenic acid (2), has been isolated from the mycelia of a cultured fungus, Penicillium sp. The structure of ravenic acid was determined by detailed spectroscopic analysis and the major isomer identified as possessing (3Z, 7E, 9E, 11E, 13E) stereochemistry.