1321 J. Indian Chem. Soc., Vol. 95, November 2018, pp. 1321-1326 Microwave-irradiated synthesis and biological evaluation of 3,5-diaryl-1-phenyl-2-pyrazolines as antibacterial and anti-inflammatory agents Anjan Kumar a *, Sradhasini Rout a , Jnyanaranjan Panda a , Biswa Mohan Sahoo b and Bimal Krishna Banik c a Department of Pharmaceutical Chemistry, Roland Institute of Pharmaceutical Sciences, Berhampur-760 010, Odisha, India b Department of Pharmacy, Vikas Group of Institution, Nunna-521 212, Vijayawada Rural, Andhra Pradesh, India E- mail: drbiswamohansahoo@gmail.com c Community Health System of South Texas, Edinburg, Texas 78539, USA Manuscript received 29 September 2018, accepted 01 November 2018 In a wide search program towards a biologically active antibacterial and anti-inflammatory agents, a series of 3,5-diaryl-1- phenyl-2-pyrazoline have been synthesized with excellent yields employing microwave techniques starting from substituted , -unsaturated carbonyl compounds which undergo cyclization reactions with phenylhydrazine. The structures of newly syn- thesized compounds were characterized and confirmed on the basis of FT-IR, 1 H NMR and mass spectral analyses. The syn- thesized compounds 3,5-diaryl-1-phenyl-2-pyrazolines had shown significant activity against Staphylococcus aureus (MTCC 87), Escherichia coli (MTCC 40), Pseudomonas aeruginosa (MTCC 424) and Proteus vulgaris (MTCC 426) by cup plate method using tetracycline-SD 037 as a reference standard. The anti-inflammatory property of 1,3,5-diaryl-1-phenyl-2-pyrazolines were screened by using carragenan induced paw edema method in Wistar rat. The anti-inflammatory activities were comparable to that of the standard drug diclofenac. The safety of 3,5-diaryl-1-phenyl-2-pyrazolines were reflected by toxicity studies. Keywords: Chalcones, pyrazolines, antibacterial, anti-inflammatory, analgesic. Introduction Considerable interest has been focused on the pyrazoline structures, some of which are known to be biologically active and important constituents of many pharmaceutical 1 and agrochemical products 2 . As an important class of biologi- cally active agent pyrazoline possesses a broad spectrum of biological activities such as antibacterial 3 , antifungal 4 , anti- depressant 5 , antidiabetic 6 , antiacetylcholinesterase 7 , anti- inflammatory, analgesic 8 , antiangiogenic and antioxidant 9 . 2-Pyrazoline being important nitrogen containing five con- taining heterocyclic compounds is most frequently studied heterocyclic compounds. With this background, it is consid- ered worthwhile to synthesize 3,5-diaryl-1-phenyl-2- pyrazolines 10 starting from simple condensation of substi- tuted acetophenones with variously substituted aldehydes to give ,-unsaturated carbonyl compounds (2a-j) and a subsequent cyclization reaction with phenylhydrazines to 3a- j. It is also important to screen them for antibacterial and anti-inflammatory activities. The chalcones possessing ,- unsaturated ketone group, when reacted with phenylhydra- zine underwent condensation and subsequent ring closure to give 2-pyrazolines (3a-j). The involvement of carbonyl group (C=O) in the reaction was indicated by the absence of absorption band at 1658 cm –1 and presence of a characteristic absorption band at 1597 cm –1 due to (C=N) stretching frequency of pyrazoline in the IR spectra of 3a. Similarly chemical shift in 13 C NMR reflected at  190.63 due to (C=O) group of 2a, which was absent in corresponding 2-pyrazoline rather represented at 135.57 due to (C=N). The 1 H NMR spectrum of 3a-j exhibited two doublets of doublets at  2.98–3.17, 3.79–3.95 and 5.20–5.67 due to Ha, Hb of (-CH 2 ) and Hc of (-CH-) proton of 2-pyrazoline respectively. Multiplets were appeared due to aromatic pro- tons with the expected chemical shift and integral value. The mass spectrum of 2a was recorded as additional evidence to the proposed structure. It exhibited molecular ion peak at m/z 208 corresponding to its molecular weight.