Synthesis of some biologically active 2,4 '-bipyridine-5-carbonitriles carrying the 4-hydroxyphenylthio moiety

A series of new 4-aryl-2'-[(4-hydroxyphenyl)thio]-6oxo-1,6-dihydro-2,4'-bipyridine-5-carbonitriles (3a-k) and 6-amino-4aryl-2'-[(4-hydroxyphenyl)thio]-2,4'-bipyridine-5-carbonitriles (4a-h) were synthesized from 4-hydroxythiophenol (1). The reaction of 4-hydroxythiophenol with 4-acetyl-2-chloropyridine yielded 1-{2-[(4-hydroxyphenyl)thio]pyridin-4-yl}ethanone (2). Further treatment of 2 with ethyl cyanoacetate in the presence of ammonium acetate with various aromatic aldehydes furnished the compounds 3a-k. On the other hand, condensation of 2 with aromatic aldehydes in the presence of alcoholic malononitrile in ammonium acetate gave compounds 4a-h. The structures of the newly synthesized compounds were established on the basis of their elemental analysis, as well as their IR, H-1- and C-13-NMR and mass spectral data. All the title compounds were subjected to in vitro antibacterial testing against two strains and antifungal screening against two fungi. Some of the compounds showed promising activity.