KINETICS OF OXIDATION OF HETEROCYCLIC SECONDARY ALCOHOLS BY N-CHLORO-R-2, C-6-DIPHENYL-T-3 METHYL PIPERIDIN-4-ONE (NCP) IN PERCHLORIC-ACID MEDIUM

An investigation of the kinetics of oxidation of epimeric piperidin-4- ols, oxan-4-ols, and cyclohexanol by N-chloro-r-2, c-6-diphenyl-t-3-me thylpiperidin-4-one (NCP) in aqueous acetic acid in the presence of pe rchloric acid shows that the reaction is first-order each in substrate and oxidant. Both H3O+ and Cl- which catalyze the reaction, exhibit a fractional order kinetics. While increase in ionic strength increases the rate slightly, an inverse dependence is observed between rate and solvent polarity. Addition of r-2-c-6-diphenyl-t-3-methylpiperidin-4- one, one of the reaction products, did not influence the rate. Also, n o kinetic isotope effect has been observed. A plausible mechanism cons istent with these observations is proposed and the relative reactiviti es of the substrates are explained on conformational grounds. (C) 1994 John Wiley & Sons, Inc.