Nineteen racemic ring A substituted analogues of the antitumor agent 2O (S)-camptothecin were prepared by total synthesis and evaluated for in vitro cytotoxic activity against KB cell culture and in vivo antileukemic activity against L1210. These compounds bore a wide variety of substitutents at Cl1 designed to confer upon the ring system a broad range of combinations of electronic, steric, and lipophilic effects. A few Clo-substituted derivatives ...
