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Synthesis of Some New Substituted Triazole Fused with Benzothiazoles and their Antibacterial Activity

TM Bhagat

The compound 4-ethoxy acetanilide (phenatidine) 1 on treatment with bromine in acetic acid followed by hydrolysis with dil. HCl/NaOH solution, yielded 2-bromo-4-ethoxy aniline 2 which on treatment with sodium thiocyanate in acetic acid afforded 2-amino-4-bromo-6-ethoxy benzothiazole 3. Compound 3 in ethylene glycol was heated at 150°C with 80% hydrazine hydrate to get 4-bromo-6-ethoxy-2-hydrazino benzothiazole 4. This hydrazino compound 4 on heating with formic acid for three hours, yielded 4-bromo-6-ethoxy 2-hydrazinoformyl benzothiazole 5. Same compound 4 when heated independently with formic acid for six hours/urea for three hours/carbon disulphide in alkali afforded 5-bromo-7-ethoxy 6/5-bromo-3-hydroxy-7-ethoxy 7/5-bromo-3-mercapto-7-ethoxy 8-1, 2, 4-triazolo [3, 4-b]-benzothiazoles. Compound 4 on heating with acetic acid/acetic anhydride gave acetyl benzothiazolyl derivative 9 which on cyclization with orthophosporic acid yielded 5-bromo-7-ethoxy-3-methyl-1, 2, 4-triazolo-[3, 4-b]-benzothiazole 10. All these newly synthesized compounds were screened for antimicrobial activity against E. coli (Gram –ve), B. subtilis (Gram +ve), E. carotovara and Xanthomonas citri using Ampicillin, Streptomycin and Penicillin as a standard for comparison.