Metabolic products of microorganisms, 256. Pyrrolams, new pyrrolizidinones produced by <i>Streptomyces olivaceus</i>

Abstract

Abstract Pyrrolams A to D ( 1 – 4 ), biosynthetically new pyrrolizidinones produced by Streptomyces olivaceus , have been discovered by chemical screening. Their structures have been determined by spectroscopic methods and by a comparison of ( R )‐dihydropyrrolam A ( 5 ) with a synthetic sample obtained from ( S )‐proline. The pyrrolams differ from the necine bases found in plant‐originating pyrrolizidine alkaloids by their less complicated structures.