Thermodynamic quantities for the oxidation of ranitidine by diperiodatocuprate(III) in aqueous alkaline medium

The kinetics of oxidation of the anti-ulcer drug, ranitidine hydrochloride (RNH) by diperiodatocuprate(III) (DPC) in alkaline medium was studied spectrophotometrically. The reaction exhibits 1:2 stoichiometry (ranitidine:DPC). The reaction is of first order in [DPC] and has less than unit order in [RNH] and negative fractional order in [alkali]. The involvement of free radicals was observed in the reaction. The oxidation has been found to proceed via a DPC-ranitidine complex, which decomposes slowly in a rate-determining step followed by other fast steps to give the products, which were identified as ranitidine sulfoxide by spot test and spectroscopic studies. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.