Abstract
The main aim of the current research is directed to find a suitable approach to construct a new annulated systems namely chromeno[3',2':5,6]pyrido[2,3-d]pyrido[2',3':4,5][1,3] thiazolo[3,2-a]pyrimidines. Treatment of 3-cyano-6,8-dimethylchromone with thiobarbituric acid gave chromeno[3',2':5,6]pyrido[2,3-d]pyrimidine, which upon treatment with chloroacetonitrile afforded 3-aminochromenopyridothiazolopyrimidine. Vilsmeier Haack formylation of the later compound produced the desired o-aminocarboxaldehyde derivative 4. Condensation of compound 4 with some active methylene nitriles namely malononitrile, cyanoacetamide, ethyl cyanoacetate, cyanoacetamide, N-phenyl-2-cyanoacetamide, 1H-benzi-midazol-2-ylacetonitrile, and malononitrile dimer produced annulated compounds 5-10 (64-76% yields). Friedla euro nder condensation of compound 4 with some active methylene ketones namely acetylacetone, ethyl cyanoacetate, diethyl malonate, and acetoacetanilide afforded annulated systems 12-15 (65-71% yields). During in vitro examination of the prepared compounds against antimicrobial activity, they appeared high activity against yeast, fungus strains and intermediate activity against all types of bacterial strains. The poly-functional product 10 exhibited notable efficiency against all types of the used microorganisms, while compound 4 present high activity against Gram-positive, yeast and fungus strains. Using spectral and analytical data, the structures of the newly synthesized products were inferred.