Synthesis, spectral characterization of some new 3-heteroaryl azo 4-hydroxy coumarin derivatives and their antimicrobial evaluation

In the present research study, 3-heteroarylazo 4-hydroxy coumarin derivatives were synthesized and evaluated in vitro for their preliminary antibacterial activities against four different pathogenic bacterial strains such as Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. Antibacterial activity of each compound was compared with standard drug, Ampicillin. The compounds were interpreted by UV, IR, 1H NMR, mass spectroscopy and X-ray diffraction studies. Solvatochromic behaviour of these compounds was also investigated by UV–vis spectra. Zone of inhibition and minimum inhibitory concentration revealed that all the products exhibited greater antibacterial potential against all bacterial strains except 4g.3-Thiazolylazo and 3-(4-phenyl thiazolylazo) of 4-hydroxy coumarin, which have been exhibiting good zone of inhibition against both gram +ve strains and gram −ve strains, where as the compound pyrazolone azo analogue 4e has tremendous antibacterial activity. Finally we concluded that the compounds having thiazole, pyrazole and triazole nucleus in individual molecular structure clubbed with potent antibacterial pharmacophore of 4-hydroxy coumain showed antibacterial activities.