2-Ethanethioamide in Heterocyclic Synthesis: Synthesis and Characterization of Several New Pyridine and Fused Azolo- and Azinopyridine Derivatives

Pyridine-2(1H)-thione derivatives 3a,b were synthesized from the reaction of 1-(phenyl-sulfanyl)acetone (1) and cinnnamonitrile derivatives 2a,b. Compounds 3a,b reacted with different halogenated reagents 7a-f to give 2-S-alkylpyridine derivatives 8a-l, which could be, in turn, cyclized into the corresponding thieno[2,3-b]pyridine derivatives 9a-l. Compounds 9d,j reacted with acetic anhydride, formic acid, carbon disulfide, phenyl isothiocyanate, and nitrous acid to yield the corresponding pyrido[3',2':4,5]thieno[2,3-d]pyrimidine 12a,b, 15a,b, 17a,b, 20a,b, and pyrido[3',2':4,5]thieno[2,3-d][1,2,3]triazinone derivatives 22a,b, respectively. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.