A variety of 5-cyano-4-methylthio-6-oxo-1, 6-dihydropyridine-3-carboxylates have been efficiently synthesized in a one-pot reaction from N-alkyl and N-aryl derivatives of 2-cyano-3, 3-bis (methylthio) acrylamides and selected β-keto esters. The reaction proceeds via potassium hydrogen carbonate mediated conjugate addition of a β-keto ester to 2-cyano-3, 3-bis (methylthio) acrylamide followed by loss of methyl mercaptan and subsequent ...