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Abstract A new series of chromeno[2,3-b]pyridines was efficiently synthesized throughout chemical transformations of 6-methylchromone-3-carbonitrile (1) with some active methylene compounds bearing –CH2-CN and –CH2-CO- moieties. Some chromeno[3’,2’:5,6]pyrido[2,3-d]pyrimidines were also synthesized. New series of heteroannulated chromeno[2,3-b]pyridines were easily and efficiently synthesized from DBU catalyzed condensation of 2-amino-6-methylchromone-3-carboxaldehyde (14) with a variety of heterocyclic enols and enamines namely, 4-hydroxycoumarin, 4-hydroxy-1-methylquinolin-2(1H)-one, 2-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one, 4-hydroxy-2H-pyrano [3,2-c]quinoline-2,5(6H)-dione, 4(6)-aminouracil and 5-amino-3-methyl-1H-pyrazole. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data. The synthesized compounds were screened in vitro for their antimicrobial activities. |