An efficient one-pot, three-component synthesis of 6-cyano-hexahydro-4H-thieno[3′,2′:5,6]pyrimido[1,2-a]quinoline-2-carboxylates and their spiro derivatives from β-enaminones

Abstract

A simple and efficient one-pot synthesis of novel thieno[3′,2′:5,6]pyrimido[1,2-a]quinoline-2-carboxylates (5a-d) and their spirooxindole derivatives (12a-d) was accomplished. Thus, the Michael addition reaction of the cyclic β-enaminone 3 with the corresponding α, β-unsaturated nitrile derivatives 4a-d in refluxing EtOH in the presence of piperidine afforded 5a-d in good yields. On the other hand, spirooxindole derivatives 12a-d were synthesized by the reaction of cyclic β-enaminone 3 with the corresponding 3-cyanomethylidene-2-oxoindoles 11a-d in refluxing EtOH.