Synthesis of Aryl- and Pyridinyl-substituted 2-Amino-6-thioxopyridine-3-carbonitrile Derivatives by Tandem Michael Addition and Cyclization Reactions

Abstract

The tandem Michael addition and cyclization of 2-, 3-, and (4-pyridinylcarbonyl) thioacetanilides with arylidenemalononitriles yielded polysubstituted pyridines and bipyridines. Tetrahydro-6-thioxopyridine-3-carbonitrile was dehydrogenated to its dihydro derivative by means of HgO or DBU. The reaction of enamines of 3-, and (4-pyridinylcarbonyl)thioacetanilides with malononitrile furnished 3,4′- and 4,4′-bipyridines.