3-Cyano-6-(2-thienyl)-4-trifluoromethylpyridine-2(1 H)-one (1) and its thiono analog 2
were prepared by the reaction of (2-thenoyl)- x, x, x-trifluoroacetone with cyanoacetamide or
cyanothioacetamide, respectively. Interaction of compound 1 with ethyl chloroacetate or
chloroacetamide led to the regioselective formation of O-alkylated pyridines 3 and 10. The latter
compounds underwent some successive reactions to furnish the promising furopyridines (4 and
7–9) and pyrazolopyridines (12–15). The reaction of 2 with chloroacetamides or chloroacetonitrile
furnished 2-functionalized 3-amino-6-(2-thienyl)-4-trifluoromethyl-thieno[2,3-b]pyridines (16a, b)
which were used as key intermediates in the synthesis of the title thienopyridines. Structures of
the newly synthesized compounds were established on the basis of their elemental and spectral
(IR, 1H NMR and mass) analyses.