SPECIAL FEATURES OF THE ELECTROCHEMICAL OXIDATION OF SUBSTITUTED 4-CARBOXY-1,4-DIHYDROPYRIDINES

Abstract

Electrochemical oxidation potentials of 1,4-dihydropyridines substituted with 4-COOH, 4-COOR, and 4‑CONRR' groups have been determined in aprotic acetonitrile by the rotating ring-disk electrode method (RRDE). The electrochemical reduction potentials of the resulting products were also determined at the ring electrode. It was established that protonated pyridines are formed in the oxidation of derivatives with and without a substituent in position 4 of the heterocycle. In the case of 4-alkoxycarbonyl substituted compounds the substituent at position 4 is generally retained. 1,4-Dihydrogenated derivatives of isonicotinic acid as a rule loose the substituent at position 4 on oxidation, and both types of product were recorded for the corresponding 4-carbamoyl derivatives. The substituent at position 9 of the heterocycle was mainly retained on electrochemical oxidation of the 3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8,9,10-decahydroacridine derivatives studied.

English Translation in Chemistry of Heterocyclic Compounds, 2000, 36 (10), pp 1177-1184

http://link.springer.com/article/10.1023/A%3A1002868600011

Authors: J. Stradins, L. Baumane, A. Kalnins, J. Uldrikis, E. Bisenieks, J. Poikans, and G. Duburs