Brønsted acidic ionic liquid catalysis: An efficient and eco-friendly synthesis of novel fused pyrano pyrimidinones and their antimicrobial activity

Abstract

A series of novel fused pyrano pyrimidinones were synthesized by the condensation of 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles with 2-oxo-2H-chromene-3-carboxylic acid under neat conditions employing an efficient, eco-friendly and reusable Brønsted acidic ionic liquid, (4-sulfobutyl)tris(4-sulfophenyl)phosphonium hydrogen sulphate as catalyst. All the synthesized compounds were characterized by their analytical and spectroscopic data and they were screened for in vitro antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis as Gram- positive, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia as Gram-negative bacterial strains and antifungal activity against Aspergillus flavus, Saccharomyces cerevisiae, Candida rugosa and Candida albicans. Compounds 2c and 2d have shown good antibacterial activity against Escherichia coli while 2g has shown marked antifungal activity against Candida rugosa. Pyrano pyrimidinones were synthesized by the condensation of 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles with 2-oxo-2H-chromene-3-carboxylic acid in the presence of Brønsted acidic ionic liquid, (4-sulphobutyl)tris(4-sulphophenyl)phosphonium hydrogen sulphate as catalyst. All the synthesized compounds were screened for in vitro antimicrobial activity.