Microwave Assisted Preparation of New Dicoumarinyl Pyrazoline Derivatives as Antimicrobials

Abstract

Some new 3-[7-methoxy-2H-1-benzopyran-2-one-4-yl]-1-(coumarin-3-yl)prop-2-en-1-ones 5a-d (dicoumarinyl chalcones) were synthesized by Wittig reaction of 3-[(triphenylphosphinyl)acetenyl]coumarins 3a-d and 7-methoxy-4- formylcoumarin 4. These chalcones were then utilized for the synthesis of dicoumarinyl pyrazolines 6a-h and 7a-l under microwave irradiation. All the synthesized compounds 5a-d, 6a-h and 7a-l were characterized by IR, 1H NMR, 13C NMR, mass spectral data and elemental analysis. The compounds were subjected to in vitro antimicrobial screening against a representative panel of bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhi) and fungi (Aspergillus niger, Candida albicans). Keywords: Antimicrobial screening, aspergillus niger, bacillus subtilis, broth dilution method, candida albicans, diastereotopic protons, dicoumarinyl chalcones, dicoumarinyl pyrazolines, escherichia coli, 7-methoxy-4-formylcoumarin, microwave irradiation, salmonella typhi, staphylococcus aureus, 3-[(triphenylphosphinyl)- acetenyl]coumarins, wittig reaction.