Metabolic Products of Microorganisms, 266. Serpentene, a Novel Polyene Carboxylic Acid from Streptomyces

From the culture filtrate of Streptomyces sp. a novel, bright yellow polyene carboxylic acid, named serpentene (1), was isolated by chemical screening methods. The structure elucidation of 1 is described. Remarkably, the C20 skeleton contains an ortho-substituted benzene ring bearing a dienoic acid and a nonatetraenyl residue. Concerning its structure and biosynthetic origin 1 is a unique secondary metabolite.