SYNTHESIS, ANTIBACTERIAL AND ANTI- MYCOBACTERIAL ACTIVITY OF SOME NOVEL3-(6-PHENYL-[1,2,4]TRIAZOLO[3,4-B][1,3,4]THIADIAZOL-3-YL)-2H-CHROMEN-2-ONE

Several 3, 6-substituted – [1,2,4] Triazolo [3,4-b][1,3,4] Thiadiazole}-2H-Chromen-2-ones(5a-5j) have been synthesized from ethyl-2-oxo-2H-chromene-3-carboxylate (1)  through a multistep reaction sequence. Compound 1 reacted with hydrazine hydrate in the presence of ethanol to give 2-oxo-2H-chromene-3-carbohydrazide (2) which on treatment with carbon disulphide and methanolic potassium hydroxide yielded corresponding potassium dithiocarbazates (3). They were then converted in to 3-(4-amino-5-sulfonyl-4H-1, 2, 4-triazol-3-yl)-2H-chromene-2-one (4) by refluxed with aqueous hydrazine hydrate. The title compounds 5a-5j was prepared by condensing 4 with various substituted aromatic acids in the presence of phosphorus oxy chloride. The synthesized compounds have been characterized by the physical (melting point and TLC) and spectral (IR, ¹NMR, ¹³C NMR and MASS) data. All the compounds were screened for their antimicrobial and anti-tubercular activities. The antimicrobial activity was examined against four types of bacteria by cup plate method. Compounds 5b, 5c, 5g, 5e & 5a showed maximum activity at both 50 and 100µg/ml concentrations. Compounds 5a, 5b, 5c, 5d, 5e, 5g, 5h & 5i showed significant activity against ATCC 27294 H37 RV strain and showed MIC at 50µg/mL.