Investigations on bongkrekic acid, the toxine from Pseudomonas cocovenenans

Reliable methods for the preparation, isolation and determination of bongkrekic acid, the antibiotic from Pseudomonas cocovenenans , are described. Bongkrekic acid (C 29 H 40 O 7 ) is shown to be a branched olefinic tricarboxylic acid with a tertiary methoxyl group in a δ‐position with respect to one of the carboxylic acid groups. Seven double bonds are present, forming at least two conjugated systems. A fragment of the structure of the completely hydrogenated bongkrekic acid (C 29 H 54 O 7 ) has been elucidated.