www.ijpsonline.com Synthesis and Antibacterial Activity of 2-(2,4- Synthesis and Antibacterial Activity of 2-(2,4- Synthesis and Antibacterial Activity of 2-(2,4- Synthesis and Antibacterial Activity of 2-(2,4- Synthesis and Antibacterial Activity of 2-(2,4- Dinitrophenyl)-3,5- Dinitrophenyl)-3,5- Dinitrophenyl)-3,5- Dinitrophenyl)-3,5- Dinitrophenyl)-3,5-diphenyl (substituted)-6-aryl- diphenyl (substituted)-6-aryl- diphenyl (substituted)-6-aryl- diphenyl (substituted)-6-aryl- diphenyl (substituted)-6-aryl- 3,3a,5,6-tetrahydro 3,3a,5,6-tetrahydro 3,3a,5,6-tetrahydro 3,3a,5,6-tetrahydro 3,3a,5,6-tetrahydro-2H-pyrazolo[3,4- -2H-pyrazolo[3,4- -2H-pyrazolo[3,4- -2H-pyrazolo[3,4- -2H-pyrazolo[3,4-d] thiazoles d] thiazoles d] thiazoles d] thiazoles d] thiazoles S. K. SAHU*, S. K. MISHRA, R. K. MOHANTA, S. P. PATTANAYAK AND C. S. PANDA 1  University Department of Pharmaceutical Sciences, Utkal University, Vani Vihar, Bhubaneswar-751 004, 1 P. G. Department of Chemistry, Behrampur University, Behrampur-760 007, India. Condensation of substituted benzaldehydes with primary aryl amines gave a series of Schiff bases(1 a 1 -e 1 ,a 2 ,b 2 ,d 2 ,b 3 - e 3 ) which, on reaction with thioglycolic acid, resulted in the formation of the corresponding 4-thiazolidinones(2a 1 - e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 ). T hese compounds, on condensation with substituted benzaldehydes in anhydrous sodium acetate, furnished 2-phenyl(substituted)-3-aryl-5-benzilidine(substituted)-thiazolidine-4-ones(3a 1 -e 1 ,a 2 ,b 2 ,d 2 , b 3 -e 3 ). The latter, on heating with 2,4-dinitrophenyl hydrazine in anhydrous sodium acetate, gave the title compounds(4a 1 - e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 ). T he structures have been established on the basis of elemental analysis and spectral data. T he title compounds have been screened in vitro for their possible antibacterial activity. Selected substituted thiazoles 1-3  as well as different  heterocyclic systems containing pyrazole ring 4-6  possess  potent biological activities. It is also believed that the  presence of N-C-S linkage is responsible for the  amoebicidal, anticonvulsant, fungicidal 7 , and antiviral  activities 8 . The present investigation deals with the  development of a new series of nitrogen heterocyclic  systems from easily available starting materials.  Substituted benzaldehydes on condensation with primary  aryl amines gave Schiff bases (1a 1 -e 1 ,a 2 ,b 2 ,d 2, b 3 -e 3 ) which,  on reaction with thioglycolic acid in refluxing benzene,  furnished the corresponding 4-thiazolidinones(2a 1 - e 1 ,a 2 ,b 2 ,d 2, b 3 -e 3 ). The latter, on condensation with  substituted benzaldehydes in the presence of anhydrous  sodium acetate and glacial acetic acid, afforded the  formation of 2-phenyl(substituted)-3-aryl-5-benzilidine  (substituted)-thiazolidine-4-ones(3a 1 -e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 ) which,  in turn, heated with 2,4-dinitrophenyl hydrazine in the  presence of anhydrous sodium acetate and glacial acetic  acid, furnished the bridgehead nitrogen heterocyclic  system, 2-(2,4-dinitrophenyl)-3,5-diphenyl(substituted)-6- aryl-3,3a,5,6-tetrahydro-2H-pyrazolo[3,4-d]thiazoles(4a 1 -e 1 ,  a 2 ,b 2 ,d 2, b 3 -e 3 ) (Scheme 1). Newly synthesised compounds  were characterised by IR, NMR spectral data and  elemental analysis. The title compounds were evaluated  *For correspondence E-mail: tutu_kh@yahoo.com for their possible antibacterial activity.  Melting points were determined in open capillaries and  were uncorrected. Purity of the compounds was checked  by TLC. IR spectra were recorded on a Jasco FT/IR  410 spectrophotometer in KBr disc.  1 H NMR spectra  were taken on a Bruker DPX, 300 MHz, spectrometer  using TMS as internal reference. C, H, and N analyses  were carried out on a Euro EA analyzer (Italy). The  bacteria used in the antibacterial activity study were  procured from the Department of Bacteriology and  Virology, Faculty of Veterinary Science and Animal  Husbandry, Orissa University of Agriculture and  Technology, Bhubaneswar.  Schiff bases(1a 1 -e 1 ,a 2 ,b 2 ,d 2, b 3 -e 3 ) and the corresponding  4-thiazolidinones(2a 1 -e 1 , a 2 ,b 2 ,d 2 ,b 3 -e 3 ) were synthesised  following the reported method 9 .  Synthesis of 2-phenyl (substituted)-3-aryl-5-benzilidine  (substituted)-thiazolidine-4-ones(3a 1 -e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 ) was  achieved by refluxing an equimolar (0.001 mol) mixture of  4-thiazolidinone derivatives (2a 1 -e 1 ,a 2 ,b 2 ,d 2, b 3 -e 3 ),  substituted benzaldehydes, and anhydrous sodium acetate  (0.082 g) in glacial acetic acid (20 ml) for 3 h. The  reaction mixture was concentrated, cooled, and poured  into ice-cold water. The solid thus separated was filtered,  washed with water, dried, and recrystallised from glacial  acetic acid. The yield and melting points are given in  May - June 2006 Indian Journal of Pharmaceutical Sciences 377