http://www.rasayanjournal.com Vol.4, No.4 (2011), 824-828 ISSN: 0974-1496 CODEN: RJCABP THIAZOLO [3, 2-α] PYRIMIDINE DERIVATIVES M. B. Buddh et al. SYNTHESIS AND BIOLOGICAL EVALUATION OF THIAZOLO [3, 2-α] PYRIMIDINE DERIVATIVES AS A NEW TYPE OF POTENTIAL ANTIMICROBIAL AGENTS. M. B. Buddh, A. H. Bapodra 1 and K. D. Ladva 2,* 1 M.D. Science College, Porbandar- 360575 (Gujarat) 2 Shree M & N Virani Science College, Rajkot-360005 (Gujarat) * E-mail: kdladva@vsc.edu.in ABSTRACT A series of 2-arylidene- 4-(4-methoxyphenyl) - 5 - (3,4-dimethyl phenylamino) carbonyl – 6 - phenyl - 4,7 dihydro thiazolo [3,2-] - pyrimidin 3-ones, were synthesized under reflux condition by a simple one pot condensation reaction of 4 – [(p-methoxyphenyl) -5- (3,4 – dimethyl) – phenyl amino carbonyl] – 6 – phenyl - 1,4 –dihydro pyrimidin -2(1H) –thiones and monochloro acetic acid, glacial acetic acid, acetic anhydride and different aromatic aldehydes in the presence of sodium acetate, where, thiopyrimidine derivatives were prepared by three component Biginelli reaction in presence of hydrochloric acid as a catalyst. The yield of both type of compounds thiopyrimidine derivatives and thiazolo pyrimidine derivatives following recrystallization from proper solvent were of the order 55 - 80%.All newly synthesized compounds were characterized by elemental analysis, IR, 1 H-NMR, and Mass spectral analysis and purity of each compounds were checked by TLC using precoated silica gel plate. The synthesized compounds have been screened for their antimicrobial activies against various gram positive and gram negative bacteria and fungi. MIC of each compound was also determined. Keywords: 1,4–dihydro pyrimidin -2(1H) –thiones, Thiazolo[3,2-] pyrimidines, Antimicrobial activity studies. © 2011 RASYAN. All rights reserved. INTRODUCTION The synthesis and pharmacological activity of condensed pyrimidine derivatives have been reported. Thiazolo [3,2-α] pyrimidine derivatives are the bioisosteric analogues of purines and are potentially bioactive molecules. Many derivatives with different substitution patterns display interesting pharmacological activities. Thiazolopyrimidines have hypoglycemic and hypolipidemic and antidiabetic 1 activities. Triazolopyrimidines have antifungal activity 2 and pyrimidine derivatives have antileshimanial activity. 3 Thus, these compounds have attracted our attention due to the wide range of biological activities associated with this scaffold. Various related compounds of these pyrimidine derivatives have biological activities ranging from kinase inhibitors, treatment of disease states associated with angiogenesis [plated derived growth factor, PDGFr, fibroplast growth factor, FGFr, and epiderma growth factor, (EGFr), 4 the analogous mitogen-activated protein (CSBP/P38) kinase inhibitor, 5 telomerase inhibitor 6 ], for treatment of arthritis, adult respiratory distress syndrome, chronic obstructive pulmonary disease, or Alzheimer’s diseae. 7 Arylazopyrimidine derivatives showed antitumor activity 8-11 and anticancer activity. 12 In light of these facts, the present work describes the synthesis of 4 – [(p-methoxyphenyl) -5- (3,4 – dimethyl) – phenyl amino carbonyl] – 6 – phenyl - 1,4 –dihydro pyrimidine -2(1H) –thione 1 and [2- arylidene- 4-(4-methoxyphenyl) - 5 - (3,4-dimethyl phenylamino) carbonyl – 6 - phenyl - 4,7 dihydro thiazolo [3,2-] – pyrimidine – 3 - ones] 2a-j and assesses their antimicrobial activity. The different aromatic aldehydes were used at second position of thiazolopyriomidine for structural modifications would inform the development of new agents with enhanced antimicrobial activity. Chemistry All thiazolopyrimidine derivatives have been synthesized by condensation of 4 - methoxyphenyl [5-(3,4– dimethyl) – phenyl amino carbonyl] – 6– phenyl-1,4-dihydropyrimidine-2(1H)–thione with monochloro