Reactions of chromone-3-carboxamides with 2-cyanothioacetamides

Chromone-3-carboxamides react with cyanothioacetamide in the presence of NaOEt in boiling ethanol to form 5-oxo-2-thioxo-1,5-dihydro-2H-chromeno[4,3-b]pyridine-3-carbonitriles (67–87% yields), whereas their reaction with N-methylcyanothioacetamide and a catalytic amount of Et₃N in boiling ethanol affords 5-cyano-2-(2-hydroxyphenyl)-1-methyl-6-thioxo-1,6-dihydropyridine-3-carboxamides in 57–73% yields.