Design, Synthesis, and Antimicrobial Evaluation of some Novel Pyridine, Coumarin, and Thiazole Derivatives

Treatment of 2-cyano-N′-(1-(pyridin-2-yl)ethylidene)acetohydrazide 1 with aromatic/heterocyclic aldehydes 2a–f gave arylidene derivatives 3a–f. Polysubstituted pyridine derivatives 4a,b were prepared either from reaction of arylidene 3a,b with malononitrile or from reaction of acetohydrazide 1 with arylidenemalononitrile 5a,b. Cyclocondensation of acetohydrazide 1 with salicylaldehyde derivatives and acetylacetone furnished pyrido-coumarins 6,7 and 2-pyridone-3-carbonitrile 8, respectively. In addition, pyrido-thiazoles 13 and 15 were obtained through reaction of 2-(1-(pyridin-2-yl)ethylidene)hydrazinecarbothioamide 11 with hydrazonyl chlorides and α-haloketones, respectively. The structures of synthesized compounds were elucidated with spectral and elemental data. The antimicrobial activity of the synthesized compounds was studied.