ISOLATION AND STRUCTURE ELUCIDATION OF THE MAJOR PHOTODEGRADATION PRODUCTS OF PIRMENOL HYDROCHLORIDE

Column chromatography, thin-layer chromatography, highperformance liqu id chromatography, nuclear magnetic resonance spectrometry, and high-r esolution mass spectrometry were employed to separate and identify the photodegradation products of pirmenol hydrochloride iperidinyl)propyl ]-alpha-phenyl-2-pyridinemethanol monohydrochloride monohydrate], a ne w antiarrhythmic drug. A methanol solution of pirmenol was irradiated using a low-pressure mercury lamp. The solution afforded four major de gradation products, three of which were identified as 3-(cis-2,6-dimet hylpiperidinyl)propyl 2-(2-pyridyl)phenyl ketone, 2-(2-pyridyl)benzoic acid, and methyl 2-(2-pyridyl)benzoate. The degradation followed appa rent-first-order reaction kinetics. In addition, the possible photodeg radation pathways are discussed with reference to reaction mechanisms.