Photochemistry of 2-(2-Furyl)-benzimidazole (Fuberidazole)

Abstract

The photodegradation of 2-(2-Furyl)-benzimidazole (Fuberidazole 1) has been reinvestigated employing advanced HPLC-UV/VIS technique and fluorescence emission and excitation spectroscopy in methanol at natural pH, in acidic medium and in aqueous solutions at pH 7 and 3, and four main products benzimidazole-2-carboxylic acid 3, its methyl ester 2, 1-methoxy benzimidazole 5, methyl 4-oxo-2-benzimidazole crotonate 7 (cis and trans isomers) besides benzimidazole 4 and 2, 2'-bibenzimidazole 6 and other side products have been isolated and characterized. The kinetics of the photodegradation process was followed independently by HPLC-UV and fluorescence emission showing a significant similarity of the curve habit; this allows to monitor a photodegradation at very low concentrations (5 • 10-5—5 • 10-6 M). The quantum yield of disappearance of Fuberidazole has been determined. © 1992, Walter de Gruyter. All rights reserved.