One-pot synthesis of diverse 4-di(tri)fluoromethyl-3-cyanopyridine-2(1H)-thiones and their utilities in the cascade synthesis of annulated heterocycles.
Diverse substituted 4-di(tri)fluoromethyl-3-cyanopyridine-2(1H)-thiones were synthesized via the Claisen condensation of alpha-methyl(methylene)ketones with di(tri)fluoroacetate, followed by the immediate Thorpe-Guareschi reaction of the preformed di(tri)fluoromethyl-1,3-diketones with cyanothioacetamide. The procedure allows facile synthesis of the di(tri)flouromethylated pyridine-2(1H)-thiones in 50-95% yields, without the need for isolation and purification of intermediates. Resultant 4-di(tri)fluoromethyl-3-cyanopyridine-2(1 H)-thiones were subsequently utilized in domino reactions to produce first various substituted thieno[2,3-b]pyridines and, then, thienopyridines polyannulated with pyridine, pyrimidine, benzodiazocine, diazepine, and pyran rings.
Rodinovskaya
Lyudmila A
LA
N. D. Zelinsky Institute of Organic Chemistry, RAS, Moscow, Russia. lar@ioc.ac.ru
Shestopalov
Anatoliy M
AM
Gromova
Anna V
AV
Shestopalov
Alexander A
AA
D006571:Heterocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D013055:Spectrophotometry, Infrared
D006571:Heterocyclic Compounds; D011725:Pyridines