The semisynthesis of RPR 121056A (4), a major metabolite of irinotecan
(CPT-11, 2), is reported starting from SN-38 (3) and an appropriate s
ide-chain precursor, and using a 2-step sequence. This semisynthesis i
s based on the 10-O-acylation of SN-38 with the conveniently protected
carbamoylchloride derivative 10 followed by cleavage of the benzylic
protecting groups by hydrogenolysis. Preliminary in vitro results show
that RPR 121056A displays no cytotoxicity. Copyright (C) 1996 Elsevie
r Science Ltd