Microwave-assisted synthesis of novel 4H-chromene derivatives bearing phenoxypyrazole and their antimicrobial activity assessment

Abstract

A new series of 4H-chromene derivatives 4a-p bearing the 5-phenoxypyrazole nucleus were synthesized under microwave irradiation by the reaction of 5-phenoxypyrazole-4-carbaldehydes 1a-h, malononitrile 2 and compounds 1,3-cyclohexanedione and dimedone (3a and 3b, respectively) in presence of NaOH as a basic catalyst. All the compounds were screened against three Gram-positive bacteria (Streptococcus pneumoniae, Clostridium tetani and Bacillus subtilis), three Gram-negative bacteria (Salmonella typhi, Vibrio cholerae and Escherichia coli) and two fungi (Aspergillus fumigatus and Candida albicans) using the broth microdilution minimum inhibitory concentration (MIC) method. The antimicrobial screening showed that the majority of the compounds were active against C. tetani and B subtilis as well as against C. albicans when compared with standard drugs. © 2012 Copyright (CC) SCS.