Electrochemical Oxidative Coupling of Hexamethylene-bis-Urazole and Arylsulfinic Acids: Synthesis of bis-Sulfonamide Derivatives

The electrochemical oxidation of hexamethylene-bis-urazole (1a) has been studied in the presence of arylsulfinic acids (3a-3c), using cyclic voltammetry and controlled-potential coulometry. A plausible mechanism for the oxidation of 1a in the presence of 3a-3c is presented. Substrate 1a was converted into bis-sulfonamide derivatives (6a-6c) through two successive Michael-type addition reactions of 3a-3c to anodically generated 4,4'-(hexane-1,6-diyl)bis(3H-1,2,4-triazole-3,5(4H)-dione) (2a). The electrochemical syntheses of 6a-6c were successfully performed in one-pot, in water without toxic reagents, using an environmentally friendly method. (c) 2012 The Electrochemical Society. All rights reserved.