Microwave assisted synthesis of novel 4h-chromene derivatives bearing phenoxypyrazole and their antimicrobial activity assess

Abstract

A new series of 4H-chromene derivatives 4(a-p) bearing 5-phenoxypyrazole nucleus has been synthesized under microwave irradiation by reaction of 5-phenoxypyrazole-4-carbaldehyde 1(a-h), malononitrile 2 and compounds (Cyclohexanedione, Dimedon) 3(a-b) in presence of NaOH as basic catalyst. All the compounds were screened against three Gram positive bacteria (Streptococcus pneumoniae, Clostridium tetani, Bacillus subtilis), three Gram negative bacteria (Salmonella typhi, Vibrio cholerae, Escherichia coli) and two fungi (Aspergillus fumigatus, Candida albicans) using broth microdilution MIC (Minimum Inhibitory Concentration) method. Upon study of antimicrobial screening, it has been observed that, majority of the compounds were found to be active against Clostridium tetani and Bacillus subtilis as well as against Candida albicans as compared to standard drugs.

Keywords

• phenoxypyrazole
• 4H-chromene
• multi-component reaction
• microwave irradiation
• antimicrobial activity