Available online at www.scholarsresearchlibrary.com Scholars Research Library Der Pharmacia Lettre, 2011, 3 (6):108-115 (http://scholarsresearchlibrary.com/archive.html) ISSN 0974-248X USA CODEN: DPLEB4 108 Scholar Research Library An efficient synthesis of some novel isoxazoles, cyanopyridines and pyrimidinthiones A N. Solankee *, K. P. Patel and R. B. Patel Department of Chemistry, B. K. M. Science College, Valsad, India ______________________________________________________________________________ ABSTRACT The title compounds (7a-f), (8a-f) and (9a-f) have been prepared from chalcones (6a-f) having s-triazine nucleus. These chalcones on cyclisation with hydroxyl amine hydrochloride in the presence of alkali and malononitrile in the presence of ammonium acetate give isoxazoles (7a-f) and cyanopyridines (8a-f) respectively. Chalcones (6a-f) on condensation with thiourea in the presence of alkali give pyrimidinthiones (9a-f). Structures of newly synthesised compounds were established on the basis of their elemental analysis, IR and 1 H NMR spectral data. Antibacterial activity (minimum inhibitory concentration MIC) against Gram-positive (S. aureus MTCC 96 and S. pyogeneus MTCC 442 ) and Gram-negative (P. aeruginosa MTCC 1688 and E. coli MTCC 443) bacteria, as well as antifungal acivity (MIC) against C. albicans MTCC 227, A. niger MTCC 282 and A. clavatus MTCC 1323 were determined by broth dilution method. Keywords Isoxazoles, Cyanopyridines, Pyrimidinethiones, Spectral data, Microbial studies. ______________________________________________________________________________ INTRODUCTION Five membered heterocycles like isoxazoles have found wide application as pharmaceutical and agrochemical agents. The synthesis of isoxazole derivatives has attracted considerable attention from organic and medicinal chemists due to their considerable bioactivity. Various biological applications have been reported for isoxazoles such as antitumor [1], analgesic [2], antimicrobial [3] and antitubercular [4] etc. Pyridine derivatives have proven to be of great importance in exhibiting and enhancing the biological activities [5]. Substituted pyridine derivatives like cyanopyridines have found to possess different biological activities such as anticancer [6], antihypertensive [7] and arthropodicidal [8] etc. Pyrimidinethiones have been found to possess antiparasitic [9], antitumor [10] and hypoglycemic [11] etc… activities. In a continuation of our work [12-15], the scope for further studies on chalcones and its derivatives, we herein report some novel isoxazoles (7a-f), cyanopyridines (8a-f) and pyrimidinethiones (9a-f). The synthesised compounds were ascertained from spectral and