Electrochemical N-arylation of azoles in MeOH using undivided electrolysis of their mixtures with 1,4-dimethoxybenzene

The reactions of 1,4-dimethoxybenzene with azoles (pyrazole, triazole, and their derivatives, as well as tetrazole) were studied by undivided amperostatic electrolysis at Pt electrodes in MeOH. The process proceeds via the formation of a 1,1,4-trimethoxyarenonium cation as the key intermediate and affords 1,1,4,4-tetramethoxycyclohexa-2,5-diene, 1,1,4-trimethoxy-4-(azol-1-yl)cyclohexa-2,5-diene, and 1,4-dimethoxy-2-(azol-1-yl)benzene as the main products. Azole and solvent molecules compete as nucleophiles during electrolysis. A fine mechanism of the process was considered. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1166–1171, May, 2005.