The leupyrrins:: A structurally unique family of secondary metabolites from the myxobacterium Sorangium cellulosum

The structurally unique leupyrrins A(1) (1), A(2) (2), B-1 (3), B-2 (4), C (5), and D (6) were isolated as one of three groups of secondary metabolites from Sorangium cellulosum strains So ce705 and So ce690. An unusually substituted gamma-butyrolactone ring and pyrrole and oxazoline rings are embedded in a nonsymmetric macrodiolide core structure, giving rise to compounds 1-6 as members of a novel class of secondary metabolites. Leupyrrin A(1) (1) shows good biological activity against various fungi and eukaryotic cells.