Kinetics and mechanism of the basic hydrolysis of nitrosoureas

Abstract

Kinetic experiments on 1,3-dimethyl-1-nitrosourea (DMNU),1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) and 1,3,3-trimethyl-1-nitrosourea (TMNU) in the presence and absence of strong nucleophiles such as HOO^– show that the basic hydrolysis of the nitrosoureas with an acidic hydrogen atom proceeds mainly by abstraction of the proton to afford an anion the subsequent decomposition of which is the rate-controlling step of the overall reaction. TMNU, which has no acidic hydrogen atom, is hydrolysed by nucleophilic attack on the carbonyl group.