~ 5 ~ The Pharma Innovation Journal 2014; 3(10): 05-09 ISSN: 2277- 7695 TPI 2014; 3(10): 05-09 © 2013 TPI www.thepharmajournal.com Received: 27-09-2014 Accepted: 08-10-2014 Deepak Swarnkar Department of Chemistry, Paher University, Udaipur ( Rajasthan) 313001, India. Rakshit A meta Department of Chemistry, Paher University, Udaipur ( Rajasthan) 313001, India. Ritu Vyas Department of Enginnering, Paher University, Udaipur ( Rajasthan) 313001, India. Correspondence: Deepak Swarnkar Department of Chemistry, PAHER University, Udaipur (Rajasthan) 313001, India. Microwave assisted synthesis of some pyrazole derivatives and their antibacterial and antifungal activity Deepak Swarnkar, Rakshit Ameta, Ritu Vyas Abstract In the present investigation, microwave assisted synthesis of 3-(4-substituted phenyl)-1-phenylprop-2-en- 1-ones (Chalcones) (1a-c) were synthesized by base catalyzed aldol condensation of p-substituted benzaldehyde with acetophenone in the presence of piperidine. 3-(4-substituted phenyl)-1-phenylprop-2-en-1-one (Chalcones) (1a-c) was carried out with hydrazine hydrate, phenyl hydrazine, isoniazid, nicotinic hydrazide or thiosemicarbezide in ethanol containing a few drops of glacial acetic acid under microwave irradiation giving 3-(4-substituted phenyl)-5-phenyl- 2,3-dihydro-1H-pyrazole (2a-c), 3-(4-substituted phenyl)-2-5-diphenyl-2,3-dihydro-1H-pyrazole (3a-c), [5-(4-substituted phenyl)-3-phenyl-2,5-dihydro-1H-pyrazole-1-yl](pyridine-4-yl)methanone (4a-c), [5- (4-substituted phenyl)-3-phenyl-2,5-dihydro-1H-pyrazole-1-yl](pyridine-3-yl)methanone (5a-c), 5-(4- substituted phenyl)-3-phenyl-2,5-dihydro-1H-pyrazole-1-carbothioamide (6a-c) derivatives. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR and 1 H NMR spectral data. The synthesized compounds have been screened for their antibacterial and antifungal activities. Keywords: 3-(4-Substituted phenyl)-1-phenylprop-2-en-1-one, Antibacterial, Antifungal activities, Microwave irradiation. 1. Introduction Microwave assisted organic synthesis has opened up some new opportunities. Microwave assisted synthesis is an eco-friendly method, where reactions occurs more rapidly, safely with higher chemical yields compared to the conventional methods of synthesis. The pyrazole unit is one of the core structures in a number of drugs. More recently extensive studies have been focused on pyrazole derivatives exhibiting anti-inflammatory 1 , anti-cancer 2 , anti-malarial [3] , antihyperglycemic [4] , analgesic [5] , anticonvulsant [6] , antidepressant 7 , antiulcer [8] , antidiabetic [9] , cytotoxic [10] , antitubercular [11] , antibacterial [12] , antifungal [13] , herbicidal and insecticidal [14-16] . A synthesis of α,β-unsaturated ketones were achieved by microwave- assisted base catalysed aldol condensation of acetophenone with p-substituted benzaldehyde. Chalcones undergo a cyclization reaction with corresponding hydrazines giving pyrazole derivatives. 2. Materials and Methods The melting points were determined in open capillary tube and are uncorrected. The IR spectra were recorded on Perkin-Elmer 157 spectrometer using KBr pellets. The 1 H NMR spectra were scanned on a DRX-300 MHz spectrometer (300 MHz) in CDCl3/DMSO-d6 using TMS as internal standard and chemical shifts are expressed in δ ppm. Purity of synthesized compounds was checked by TLC using silica gel-G. Spots were exposed in an iodine chamber. General procedure for preparation of chalcone (1a-c) A convenient route for the synthesis of α,β-unsaturated ketones (Chalcone) was achieved by the reaction of p-substituted benzaldehyde (0.005 mol) with acetophenone (0.005 mol) in the presence of piperidine, under microwave irradiation at 5 sec intervals. The specific reaction time was kept 2 min and then the reaction mixture was cooled in crushed ice. Progress of the reaction was monitored by TLC method. The solid thus obtained was filtered, washed with water, dried and purified by recrystallization from ethanol.