Original Articles: 2011 Vol: 3 Issue: 1
Synthesis and analgesic activity of triazolothiadiazoles and triazolothiadiazines encompassing 3Ã?¢Ã?â?¬Ã?â??nitronaphtho[2,1-b]furan
Abstract
The required starting material 3-nitronaphtho[2,1-b]furan-2-carhohydrazide 1 was synthesized from ethy1 3-nitronaptho[2,1-b]furan-2-carboxylate. The compound 1 on reaction with carbon disulphide and hydrazine hydrate in presence of alkali produced the key intermediate 3-nitro-4- amino-5-naphtho[2,1-b]furan-2-y1-4H-1,2,4-triazole-3-thiol 2. 1,3,4-Thiadiazole moiety was constructed on triazole ring system by adopting three different experimental protocols to obtain 3-nitronaphtho[2,1b]furan-2-yl-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole-6(5H)-thione 4, 3- nitronaphtho[2,1-b]furan-2-yl-6-aryl-5,6-dihydro[1,2,4 triazolo[3,4-b][1,3,4]thiadiazoles 5(ad). and 3-nitronaphtho[2,1-b]furan-2-yl-6-aryl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles 6(a-c). To investigate the synthetic utility of compound 2 in the synthesis of bridge head six membered heterocycles, it was treated with chloroacetic acid and sodium acetate in ethanol. This reaction furnished 3-nitronaphtho[2,1-b]furan-2-y1-5H-[1,2,4]triazolo [3,4-b][1,3,4]thiadizin-6(7H)– one 3. The newly synthesized compounds were characterized by analytical and spectral studies. All the compounds were evaluated for analgesic activity by acetic acid induced writhing method by using Swiss albino mice.