ELECTROCHEMICAL-BEHAVIOR OF AN UNSYMMETRICAL 4-(O-NITROPHENYL)-1,4-DIHYDROPYRIDINE IN PROTIC MEDIUM

The electrochemical behaviour of 3-cyano-5-methoxycarbonyl-2,6-dimethyl-4(o-nitrophenyl)-1,4-dihydropyridine and the corresponding N-methyl derivative have been investigated in hydroalcoolic medium. The 4 electron reduction leads to an amino-benzonaphtyridine N-oxide (cyclization from the reaction of the hydroxylamino group with the cyano substituent) when performed in acidic medium; in basic medium, the same reduction leads to a cyclic hydroxamic acid resulting from the condensation of the hydroxylamino group with the ester substituent. Anodic oxidations give the corresponding pyridine or pyridinium derivatives; subsequent reductions of the latter always lead to cyclic hydroxamic acids.