Hydrolysis of the cis-phenyl ester of thymidine 3',5'-cyclic monophosphate: ph-dependent competition between depyrimidination and phosphotriester hydrolysis uia CO and PO bond ruptures

摘要

Hydrolytic reactions of the cis-phenyl ester of thymidine 3',5'-cyclic monophosphate (1a) have been followed by HPLC over a wide pH range. Under acidic conditions (pH<4) two reactions compete: depyrimidination (celavage of the N-glycowidic bond) and phosphortiester hydrolysis to a mixture of three phosphodiesters, uiz. thymidine 3',5'-cyclic monophosphate (2) and thymidine 3'- and 5'- (phenyl phosphates) (3 and 4). Depyrimidination proedominates (>80/100) at pH<1 and showws first- order dependence on acidity.