Semisynthesis of RPR 121056A, a Major Metabolite of Irinotecan (CPT‐11) .

Abstract The semisynthesis of RPR 121056A ( 4 0, a major metabolite of irinotecan (CPT-11, 2 ), is reported starting from SN-38 ( 3 ) and an appropriate side-chain precusor, and using a 2-step sequence. This semisynthesis is 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.