Microwave-assisted multi-component synthesis of indol-3-yl substituted pyrano[2,3-c]pyrazoles and their antimicrobial activity

A series of pyrano[2,3-c]pyrazole derivatives of indole was synthesized by multi-component reactions using the conventional and microwave irradiation approach. Particularly valuable features of this method include high yield, broad substrate scope, shorter reaction times and straightforward procedure. Antimicrobial screening of the synthesized derivatives against eight human pathogens, namely Bacillus subtilis, Clostridium tetani, Streptococcus pneumoniae, Salmonella typhi, Vibrio cholerae, Escherichia coli, Aspergillus fumigatus and Candida albicans, was realized by employing the broth microdilution minimum inhibition concentration method, as recommended by National Committee for Clinical Laboratory Standards (NCCLS).