Novel heteroannulated chromeno[3′,2′:5,6]pyrido[2,3-d][1,2,4]triazolo[4,3-a] pyrimidines and chromeno[3′′,2′′:5′,6′]pyrido[2′,3′:4,5]pyrimido[2,1-c][1,2,4] triazines: Synthesis, characterization and antimicrobial evaluation

Abstract

The novel 2-hydrazinyl-8-methyl-4H-chromeno[3′,2′:5,6]pyrido[2,3-d]pyrimidine-4,6(3H)-dione (4) was efficiently synthesized and characterized by different spectroscopic techniques. Compound 4 was utilized for the formation of two novel categories of heteroannulated compounds containing chromenopyridopyrimidines. Reaction of compound 4 with some mono-electrophilic reagents namely diethyl carbonate, carbon disulfide, triethylorthoformate, acetyl chloride and benzoyl chloride afforded chromeno[3′,2′:5,6]pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidines 5–9. While, treatment of compound 4 with a diversity 1,2-bielectrophilic reagents namely chloroacetic acid, phenacyl bromide, oxalyl chloride, chloroacetonitrile, bromomalononitrile,3-chloropentane-2,5-dione and ethyl 2-chloro-3-oxobutanoate produced chromeno[3′′,2′′:5′,6′]pyrido[2′,3′:4,5]pyrimido[2,1-c][1,2,4]triazines 10–16. The antimicrobial evaluation of the synthesized products appeared variable inhibitory effect toward the tested microorganisms. Spectral and elemental microanalysis were used for structure elucidation of the new synthesized compounds.