Decomposition and Stabilization of Drugs. XIX. Kinetic Studies on the Hydrolysis of Bencyclane Fumarate

抄録

Bencyclane fumarate (I) was decomposed in aqueous buffer solution from pH 1.2 to 6.3 in order to examine its stability and mechanism of hydrolysis. It was found that I was hydrolyzed with pseudo first-order kinetics, and the pH-rate profile was a straight line of slope-1. The activation energy (Ea) was calculated to be 33.0 kcal/mol from Arrhenius plots. Further examination of the decomposition mechanism through kinetic analysis suggested a new pathway where I first formed a carbonium ion intermediate in an acidic solution then decomposed immediately into an alcohol and two olefins by hydration and dehydration, respectively.