Kinetics and Mechanism of Reversible Hydrolysis of 11b-Methylbenzodiazepinooxazoles

Abstract

Reversible hydrolyses of benzodiazepinooxazoles having an 11b-methyl group and of oxazolam having a 7-methyl group were investigated kinetically in buffers of various pH's and at 25°C, in the light of the light of the difference in the reversibility of the hydrolysis between 11b-methyl- and 11b-phenyl- (e.g., oxazolam itself) benzodiazepinooxazoles. The irreversibility of the hydrolysis of 11b-phenylbenzodiazepinooxazoles is considered to arise from the larger size of the phenyl group than the methyl group in addition to the intramolecular hydrogen bonding between carbonyl oxygen of benzophenone and amide hydrogen at the ortho position. Substituents at the 2-position of 11b-methylbenzodiazepinooxazole do not greatly affect the reversible hydrolysis.