Kinetics and Mechanism of Oxidation ofGabapentin by N-bromosuccinimide inAqueous Alkaline Medium. Comparing to theKinetics of Oxidation by N-bromosuccinimidein Aqueous Acid Medium

摘要

The kinetics of oxidation of gabapentin (GBP) by N-bromosuccinimide (NBS) in an alkaline medium has been investigated. The oxidation reaction showed unique kinetics that greatly differed on going from acid to base medium. In an acid medium (pH=2.52), the reaction rate showed first order dependence on [NBS], fractional order dependence on both [GBP] and [H+] and increased with temperature over (303–321oK) range. In an alkaline medium, the rate showed first order dependence on [GBP], fractional order on [H+] over (1.99-39.80) x10-9 range and zero order dependence on [NBS]. It is noteworthy that the reaction rate decreased with temperature over the range studied. An inner-sphere mechanism for the oxidation pathway supported by free radicals intervention was proposed.