Pyrrocidines A and B, New Antibiotics Produced by a Filamentous Fungus.

Abstract Pyrrocidines A ( 1 ) and B ( 2 ), two new antibiotics, containing rare 13-membered macrocycles, were isolated from the fermentation broth of a fungus, LL -Cyan426. Pyrrocidine A ( 1 ) exhibited potent activity against Gram-positive bacteria, including drug-resistant strains. The structures of these compounds were established using spectroscopic methods.