Synthesis and anti-microbial screening of some new 6, 7, 8, 9-Tetrahydro-5H-5-(2'-hydroxyphenyl)-2-(4'substitutedbenzylidine)-3-(4-nitrophenylamino) thiazoloquinazoline derivatives

A series of some new 6, 7, 8, 9-Tetrahydro-5H-5(2'-hydroxyphenyl)-2-(4'-fluorobenzylidine)-3-(4nitrophenyl amino) thiazolo quinazoline (4a-4d) and 6, 7, 8, 9-Tetrahydro-5H-5-(2'-hydroxy phenyl)2-(4'-substituted benzylidine)-3-(4-nitrophenyl amino) thiazolo quinazoline (5a-5d) derivatives were synthesized. The in vitro anti-bacterial and anti-fungal activities were determined by paper disk diffusion method. The minimum inhibitory concentrations (MIC) of the compounds were also determined by agar streak dilution method. Most of the synthesized compounds exhibited significant anti-bacterial and anti-fungal activities. Among the synthesized compounds 6, 7, 8, 9-Tetra hydro-5H-5-(2'-hydroxy phenyl)-2-(4'-methoxy benzylidine)-3-(4-nitro phenyl amino)thiazolo quinazoline 5a, 6, 7, 8, 9-Tetrahydro-5H-5-(2'-hydroxy phenyl)-2-(3', 4'-dimethyl benzylidine)-3-(4nitrophenyl amino) thiazolo quinazoline 5b and 6, 7, 8, 9-Tetrahydro-5H-5-(2'-hydroxyphenyl)-2(4'-fluoro benzylidine)-3-(4-nitro phenylamino) thiazolo quinazoline 5d exhibited most potent in vitro antimicrobial activity with MIC of (9.4, 10.2, 10.4, 10.2, 11.3, 12.1, 12.7, 14.6, 18.7), (10.3, 14.2, 11.6, 13.4, 13.6, 13.8, 14.6, 13.1, 14.5) and (12.5, 10.3, 14.1, 10.6, 13.4, 19.8, 17.8, 11.2, 13.6) at 100 μg mL⁻¹ against Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Bacillus cereus, Escherichia coli, Pseu domonas aeruginosa, Klebsiella pneumoniae, Aspergillus niger and Candida albicans.