A Two-Step Synthesis of Selected 1,2,3,4-Tetrahydroquinoxaline Derivatives from N-Aryl-2-nitrosoanilines and Arylidenecyanoacetic Esters

Abstract

Reaction of N-aryl-2-nitrosoanilines with alkyl aryl­idenecyanoacetates in the presence of Et₃N in MeCN leads to substituted 1,2,3,4-tetrahydroquinoxaline derivatives in reasonable yields. The reaction comprises nucleophilic addition of the nitrosoaniline to the Michael acceptor followed by cyclization involving the nitroso group. Since the reactive nitrogen groups in N-aryl-2-­nitrosoanilines are of opposite character the reaction is regioselective and additionally it was found to be diastereoselective.