Structure-activity relationship of a novel antitumor ansamycin antibiotic trienomycin A and related compounds.

Various derivatives of trienomycin A (1) were prepared and tested for cytocidal activities. All the derivatives except for 22-O-methyltrienomycin A (5) showed reduced cytotoxicity compared with 1. It is concluded that the existence of a triene moiety, free 13-OH and an acyl group at C-11 owe important role for cytocidal activity.