ELECTROCHEMICAL BEHAVIOUR OF BENZIMIDAZOLES II. PREPARATION OF A BIOLOGICALLY ACTIVE COMPOUND BY ELECTROREDUCTIVE DECARBOXYMETHYLATION

Abstract

Based on steady-state voltammetric experiments, preparative electrochemical reduction of the 1 ,3,5-triazino-(1 ,2-a)-benzimidazole-1 (2H )-carboxylic acid-3-dodecyl-3,4-dihydro-, methylester 1 was carried out on Hg. Pb and Pt cathodes, in DMF /TBAP and MeCN /TBAP electrolytes. In all cases reduction resulted in the decarboxymethylated derivative 2 by cleavage of the carbon-nitrogen bond. The best product and current yield for 2 formation could be achieved when Pt was used as cathode material, MeCN /TBAP as electrolyte, a divided cell and constant current density in the range 15-25 mA/cm2 , or working at constant potential between 1.6 and 2.3 V vs Ag/ AgI electrode. The reaction mechanism seemed to that of the activated halides.