Bridgehead nitrogen heterocyclic systems:: Facile synthesis and antimicrobial activity of thiadiazolo [2′,3′:2,1] imidazolo [4,5-b] quinoxaline, imidazolo [2,1-b]-1,3,4-thiadiazoles and their brominated products

The synthesis of 2,6-diarylimidazo [2, 1 -b]-1,3,4-thiadiazoles 2, 2-(p-hydroxyphenyl)thiadiazolo [2',3':2,.1] imidazo [4,5-b] quinoxaline 4 has been achieved by the reaction of 2-amino-5-(p-hydroxyphenyl)-1,3,4-thiadiazole 1 with (alpha-haloketones, 2,3-dichloroquinoxaline respectively. Bromination of compound 2 furnishes 5-bromo-2,6-diaryl-imidazo [2,1-b]-1,3,4-thiadiazoles 3. The antimicrobial and antifungal activities of some of the compounds have also been evaluated.