Microwave Assisted Improved Method for the Synthesis of Pyrazole Containing 2,4,-Disubstituted Oxazole-5-one and their Antimicrobial Activity

Abstract

Disubstituted oxazol-5-one and pyrazoles are known to exhibit various biological activities. Therefore, in this work, we designed pyrazole containing 2,4-disubstituted oxazol-5-one(3a-g)as a new class of antimicrobial agents. Synthesis of titled compounds was carried out by two different methods. In the first method (conventional Method A), disubstituted oxazol-5-one(3a-g)was prepared by reacting 1-phenyl-3-p-tolyl-1H-pyrazole-4-carbaldehyde(1a-g)with hippuric acid(2)and sodium acetate, in an acetic anhydride for 2.5 - 4 h. In the second method (Method B), the above reaction was carried out under microwave assistance. Compared to the conventional method, the microwave-assisted synthesis of 3,4,5-trisubstituted imidazoles demonstrate several advantages, in terms of reaction time and overall yield. All the test compounds were evaluated forin vitroantibacterial and antifungal activities. In general, compounds with electron withdrawing groups showed good antibacterial and antifungal activities. Among the compound tested, compound(3d)showed highest activity.