ISSN: 2320 - 4230 Journal of Drug Discovery and Therapeutics Available Online at www.jddt.in CODEN: - JDDTBP (Source: - American Chemical Society) Volume 3, Issue 28, May, 2015, 39-44 39 *Corresponding author: Karumudi Bhavya Sai |E-mail: rajaneeraja@gmail.com Research Article SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL SCREENING OF NOVEL SERIES OF BIS- IMIDAZO[1,2-a]PYRIDINE DERIVATIVES Gollapalli Naga Raju 1 , Karumudi Bhavya Sai* 2 , Jagarlamudi Rajarajeswari 2 , Varanasi Vasanthi Krishna Priya, Pendyala Vandana 1 , Rama Rao Nadendla 1 1 Department of Pharmaceutical Analysis 2 Department of Pharmacy Practice Chalapathi Institute of Pharmaceutical Sciences, Guntur, India. Received 04 May 2015; Accepted 16 May 2015 ABSTRACT A novel series of Bis-imidazo[1,2-a]pyridine derivatives were synthesized from 2-(4-Fluorophenyl)-6-methylH- imidazo[1,2-a]pyridine. All the synthesized compounds have been characterized by using elemental analysis, FT-IR, 1 H NMR, 13 C NMR spectroscopy and further supported by mass spectroscopy. Purity of all the compounds has been checked on thin layer chromatographic plate and HPLC technique. All the synthesized compounds were tested for their antibacterial and antifungal activity (MIC) in vitro by broth dilution method with two Gram-positive bacteria, two Gram- negative bacteria and two fungal strains. The biological activities of the synthesized compounds have been compared with standard drugs Ampicillin and Greseofulvin. The compounds exhibited significant antibacterial and moderate antifungal activities. These compounds can be further exploited to get the potent lead compounds. The detailed synthesis and the antimicrobial screening of the new compounds are reported. Keywords: Imidazo[1,2-a]pyridine, Antibacterial activity, Antifungal activity. INTRODUCTION Imidazo[1,2-a]pyridines, a novel class of pharmaceutical compounds exhibit a broad range of biological activities. Besides, imidazo[1,2-a]pyridine scaffold is found in a number of marketed drug formulations, such as zolimidine (an antiulcer drug), zolpidem (ahypnotic drug), and alpidem (a nonsedative anxiolytic). As a result, numerous reports have described the structural modifications of this scaffold with the aim of developing novel therapeutic agents. Bis imidazo[1,2-a]pyridine derivatives are important intermediates in organic synthesis, especially in the synthesis of biologically active and medicinally useful agents. For instance, they are widely used in the synthesis of cyclin-dependent kinases (CDK) inhibitors, sleep inducers, anticonvulsant agents, etc. It has long been known that imidazo [1, 2-a] pyridine derivatives exhibited diverse biological activities like antibacterial 1, 2 , Antitumor 3, 4 , Antiinflammatory 5, 6 , antiviral 7, 8 , anti malarial 9, antifungal 10, 11 , antimicrobial 12 , antiprotozoal 13, 14 and antitubercular 15 agents. Considering the above observations and in connection to previous publications involving the synthesis of new biologically active heterocycles. Thus the efficient synthesis novel series of Bis-imidazo[1,2-a]pyridine derivatives compounds still represent highly pursued target. EXPERIMENTAL Material and Methods: Melting points were determined in open capillary tubes and are uncorrected. Formation of the compounds was checked by TLC on silica gel-G plates of 0.5 mm thickness and spots were located by iodine and UV light. All compounds were purified by recrystallization with suitable organic solvents. IR spectra were recorded on Brooker-ALPHA FT-IR instrument using KBr pellet method. Mass spectra were recorded on Shimadzu GC-MS-QP- 2010 model using direct inlet probe technique. 1 H NMR and 13 C NMR was determined in CDCl 3 solution on a Bruker Ac 400 MHz spectrometer. Purity of the synthesized compounds was checked by HPLC Agilent. The results are in agreements with the structures assigned. Elemental analysis of the all the synthesized compounds was carried out on Euro EA 3000 elemental analyzer and the results are in agreements with the structures assigned. Synthesis of 2-(4-Fluorophenyl)-6-methylH-imidazo[1,2- a]pyridine: A solution of 5-methylpyridin-2-amine (1.08 g, 0.01 mol) in methanol (10 ml) was added to 2-chloro-1- (4-fluorophenyl)ethanone (1.72 g, 0.01 mol) and the reaction mixture was refluxed with stirring for 6 hour in the presence of catalytic amount of triethylamine. After the completion of reaction, cool the content, the solid separated was filtered and dried in vacuo. Yield 68%, M.P