Reactions with Hydrazonoyl Halides 62: Synthesis and Antimicrobial Evaluation of Some New Imidazo [1,2-a]pyrimidine, Imidazo [1,2-a]pyridine, Imdazo [1,2-b]pyrazole, and Quinoxaline Derivatives Abdou O. Abdelhamid, a * Eman K. A. Abdelall, b and Yasser H. Zaki c a Department of Chemistry, Faculty of Science, Cairo University, Giza 12613, Egypt b Department of Organic Chemistry, Faculty of Pharmacy, Beni-Suef University, Egypt c Department of Chemistry, Faculty of Science, Beni-Suef University, Egypt *E-mail: abdelhamid45@yahoo.com Received August 1, 2009 DOI 10.1002/jhet.307 Published online 23 February 2010 in Wiley InterScience (www.interscience.wiley.com). 3-Arylazo-2-(4-methyl-2-phenylthiazol-5-yl)imidazo[1,2-a]pyrimidine, 2-(4-methyl-2-phenyl-1,3-thia- zol-5-yl)-3-phenylazoimidazo[1,2-a]pyridine, 3-arylazo-2-(4-methyl-2-phenylthiazol-5-yl)-6-phenyl-5H- imidazo[1,2-b]pyrazole, 6-(4-methyl-2-phenyl-thiazol-5-yl)-5-phenylazo3-phenyl-imidazo[2,1-b]thiazole, 3-(4-methyl-2-phenylthiazol-5-yl)-2-phenylhydrazino-(1H)-quinoxaline, 3-(4-methyl-2-phenylthiazol-5- yl)- 2-phenylazoquinoxaline, 3-(4-methyl-2-phenylthiazol-5-yl)-2-phenylhydrazinobenzo-[1,4] thiazine, 3-(4-methyl-2-phenyl-thiazol-5-yl)-2-phenylhydrazinobenzo[1,4]oxazine, and 3-(4-methyl-2-phenyl- thiazol-5-yl)-2-phenylazo-1H-pyrido[2,3-b]pyrazine derivatives were synthesized via reaction of 2-(4-methyl- 2-phenyl-1,3-thiazol-5-yl)-2-oxo-N-arylethanehydrazonoyl bromide with each of 2-aminopyrimidine, 2-ami- nopyridine, 3-aminopyrazoles, 2-amino-4-phenylthiazole, o-phenylenediamine, o-aminothiophenol, o-amino- phenol, or 2, 3-diaminopyridine, respectively. All structures of the newly synthesized compounds were elucidated by elemental analysis, spectral data, and alternative synthetic route whenever possible. The entire newly synthesized compounds are tested toward different microorganisms. J. Heterocyclic Chem., 47, 477 (2010). INTRODUCTION Our continuous interest in the chemistry of hydrazo- noyl halides [1–9] originates from our persistent trials to obtain pyridines, pyrimidines, pyridazines, and their ana- logs. The importance of such compounds lies in their diverse pharmaceutical activities, namely antibacterial [10,11], antidiabetic [12], anti-HIV [13], antiviral [14,15], and analgesic activities. We report herein the reactivity of 2-(4-methyl-2-phenyl-1,3-thiazol-5-yl)-2- oxo-N-arylethanehydrazonoyl bromides toward 2-amino- pyrimidine, 2-aminopyridine, 3-aminopyrazoles, 2- amino-4-phenylthiazole, o-phenylenediamine, o-amino- thiophenol, o-aminophenol, and 2,3-diaminopyridine. RESULTS AND DISCUSSION Treatment of 2-aminopyrimidine (2) with the appro- priate 2-(4-methyl-2-phenylthiazol-5-yl)-2-oxo-N-aryle- thanehydrazonoyl bromide (1a, b) in ethanol gave 3- arylazo-2-(4-methyl-2-phenylthiazol-5-yl)imidazo[1,2-a] pyrimidine (3a, b) in a good yield (Scheme 1). Struc- ture 3 was elucidated by elemental analysis, spectral V C 2010 HeteroCorporation March 2010 477