Utility of Nitriles in Synthesis of Pyrido[2,3-d]pyrimidines, Thiazolo[3,2-a]pyridines, Pyrano[2,3-b]benzopyrrole, and Pyrido[2,3-d]benzopyrroles

3-Aryl-2-cyanoacrylonitriles ( 1a , b ) reacted with 6-aminothiouracil, 2-ethoxy carbonylmethyl-4-oxo-Δ2-thiazoline, 2-cyanomethyl-4-oxo-Δ2-thiazoline and indan-2-one to give pyrido[2,3-d]pyrimidines, thiazolo[3,2-a]pyridines, pyrano [2,3-b]benzopyrrole and pyrido[2,3-b]benzopyrrole, respectively. The IR, MS and 1H-NMR of the synthesized compounds were discussed. The antimicrobial activity of some of the synthesized compounds was tested.