ChemInform Abstract: Synthesis of 2,6-Diamino-3,5-dicyano-4-ethyl-4H-thiopyran and Its Recyclization into 6-Amino-3,5-dicyano-4-ethylpyridine-2(1H)-thione.

✍ Scribed by V. D. DYACHENKO; S. G. KRIVOKOLYSKO; V. P. LITVINOV

• Publisher: John Wiley and Sons
• Year: 2010
• Weight: 31 KB
• Volume: 28
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.199704161

✦ Synopsis

Synthesis of 2,6-Diamino-3,5-dicyano-4-ethyl-4H-thiopyran and Its Recyclization into 6-Amino-3,5-dicyano-4-ethylpyridine-2(1H)-thione.

-Three component condensation of propionaldehyde with malononitrile and cyanothioacetamide provides the title diaminothiopyran (IV) which recyclizes at reflux into the thermodynamically favoured pyridinethione (V). The thione (V) can be smoothly S-alkylated and further transformed into thienopyridines (VIII).