The structures of additional teleocidin class tumor promoters.

The known tumor promoter des-O-methylolivoretin C, and a new possible tumor promoter, des-N-methylteleocidin B-4, were isolated from Streptomyces mediocidicus and the structure of the latter metabolite was elucidated by chemical correlation with the known teleocidin B-4. The structures of teleocidin B-2 and a new metabolite, olivoretin E, obtained from Streptomyces mediocidicus and Streptoverticillium olivoreticuli respectively, were determined by means of single-crystal X-ray diffraction analysis.