Construction, characterization, and antimicrobial evaluation of the novel heteroannulated chromeno[2′′,3′′:6′,5′]pyrido[2′,3′-d] [1,3] thiazolo[3,2-a]pyrimidines

Abstract

The reaction of chromone-3-carbonitrile with thiobarbituric acid afforded 2-thioxochromeno[3′,2′:5,6]pyrido[2,3-d]pyrimidine-4,6(1H,3H)-dione, which utilized as a building block for construction of a novel heteroannulated compounds containing chromenopyridothiazolopyrimidine moiety. Reactions of the starting compound with a variety of bielectrophilic reagents namely; chloroacetonitrile, bromomalononitrile, 3-chloropentanedione, ethyl 2-chloro-3-oxobutanoate, phenacyl bromide, chloroacetic acid, dibromoethane, and oxalyl chloride afforded the first known chromenopyridothiazolopyrimidines. Cyclization of the starting compound with 2,3-dichloroquinoxaline gave the linear hepta-annulated chromenopyridopyrimidothiazoloquinoxaline. In addition, chromenopyridopyrimido thiazolopyrimidines were efficiently synthesized. The antimicrobial activity was evaluated for the prepared compounds and some of them seemed notable activity against the tested microorganisms. Analytical and spectral data confirmed the structures of the new products.