Synthesis of OSW-1 analogs with modified side chains and their antitumor activities

Four analogs of OSW-1 (1–4) with modified side chains on the steroidal skeleton were synthesized following modification of our previous route for the total synthesis of OSW-1. Testing of the analogs against growth of tumor cells demonstrated that the 22-one function and the full length of the side chain of OSW-1 were not required for the antitumor action of OSW-1.