Synthesis of 2,6-diamino-3,5-dicyano-4-ethyl-4H-thiopyran and its recyclization to 6-amino-3,5-dicyano-4-ethylpyridine-2(1H)-thione

Article abstract of DOI:10.1007/BF01176972

The triple condensation of propionaldehyde, malononitrile, and cyanothioacetamide gives 2,6-diamino-3,5-dicyano-4-ethyl-4H-thiopyran, which recyclizes to give 6-amino-3,5-dicyano-4-ethylpyridine-2(1H)-thione. This thione was used to synthesize substituted 2-alkylthiopyridines and the corresponding thieno[2,3-b]pyridines. 1997 Plenum Publishing Corporation.