Schiff base chromones from natural Benzofuran as potential scaffold for anti-Staphylococcus aureus: synthesis of cis and trans isomers, in vitro and in silico studies.

Three hydrazone chromones 3a-c (3a, b in trans isomer while 3c was a mixture) and three hydrazone furanochromones 7a-c (7a in trans while 7b, c in cis) carrying carboxylic acid or its bioisostere sulphonamide group were synthesised. Simple method to synthesis cis or trans hydrazones was explored with explanation to the effect of substitution on the stabilisation of the isomers through IMHB. Compounds screened for their anti-Staphylococcus aureus and anti-Candida albicans activity, four compounds 3a, b and 7a, c showed moderate to weak anti-Staphylococcus aureus activity and one compound 7c showed weak anti-Candida albicans activity. The 4-carboxylic acid substitution 3a and 7a was better for anti-Staphylococcus activity than 3-carboxylic acid substitution 3b and 7b. For 7a-c 4-sulphonamide substitution 7c showed better activity than 4-carboxylic acid substitution 7a. Pharmacophore study showed the similarity between 3a, 7c and pteroic acid which suggest the possibility of these classes to act on DHPS enzyme.