Construction and biological evaluations of some novel chromeno[2,3-b]pyridines and chromeno[2,3-b]- quinolines using 6-methylchromone-3-carbonitrile

Abstract

Reaction of 6-methylchromone-3-carbonitrile (1) with acetylacetone under basic conditions afforded 3-acetyl-2,7-dimethyl-5H-chromeno[2,3-b]- pyridin-5-one (2) which utilized as a starting substrate. Condensation of compound 2 with a variety of amines and hydrazines produced chromeno[2,3-b]- pyridines linked variable compounds in the same molecular frame. Condensation reaction of compound 2 with variable carbon nucleophilic reagents namely; malononitrile, ethyl cyanoacetate, malononitrile dimer, 1H-benzimidazol- 2-ylacetonitrile and dimedone produced heteroannulated chromeno[2,3-b]- quinolines 18-22. The synthesized compounds were screened in vitro for their antimicrobial activity and revealed remarkable inhibitory effects against the selected microorganisms. Structures of the newly synthesized products have been deduced upon the help of elemental analysis and spectral data (IR, 1H NMR, 13C NMR and mass spectra).