Microwave Assisted Synthesis of 7-Substituted-6-Fluoro-Benzothiazolo-Tetrazole for Antimicrobial Studies

S. M. Hipparagi1, U. K. Majumder2, V. Suresh Kumar1 B. Parikshit1 and M. Geethavani1

¹Department of Pharmaceutical Chemistry, K.L.E.S’s College of Pharmacy, Rajajinagar, Bangalore - 560 010 (India) ²Pharmaceutical Technology Department, Jadhavapur University, Kolkata - 700 032 (India)

7-Chloro-6-fluoro-benzothiazol-2-yl-amine was synthesized from 3-Chloro-4-fluoro phenylamine, which on reaction with hydrazine hydrate in a modified microwave oven containing a reflux condenser, magnetic stirrer, and thermostat control yielded 7-chloro-6-fluoro-benzothiazol-2-yl-hydrazine as the intermediate that is ultimately converted to 7-chloro-6-fluoro-benzothiazolo[2,3-d]-1,2,3,4-tetrazole by cyclization with sodium nitrite. Various derivatives were prepared by replacing the chlorine atom of 7-chloro-6-fluoro-benzothiazolo[2,3-d]-1,2,3,4-tetrazole with benzamide and alkoxides. Oxidation of the sulphur of the benzothiazole moiety resulted in sulfone and sulfoxide derivative of benzothiaozolo-tetrazole, which were subjected to chlorine substitution to yield the sulfone and sulfoxide derivatives of 7-substituted-6-fluoro-benzothiazolo[2,3-d]-1,2,3,4-tetrazole. The synthesized compounds have been characterized by analytical and spectral studies (IR and 1H NMR) and screened for their antimicrobial activity. The yield of the compounds synthesized by using microwave oven was more when compared to conventional method.

Benzothiaolo-tetrazole; antimicrobial activity