Regioselective synthesis and pharmacological activities of spirodibenzo[a,d]cycloheptene-5,2′-[1,3,4]thiadiazole derivatives

Some new 3^′,5^′-substituted-5H,3^′ H-spirodibenzoa, d]cycloheptene-5,2^′-1,3,4]thiadiazole and 10,11-dihydro-5H,3^′ H-spirodibenzoa, d]cycloheptene-5,2^′-1,3,4]thiadiazole derivatives 3a–n were regioselectively synthesized under 1,3-dipolar cycloaddition of 5-thiooxo-5H-dibenzoa, d]cyclo-heptene and 5-thiooxo-10,11-dihydro-5H-dibenzoa, d]cycloheptene with a variety of nitrilimines (generated in situ via dehydrohalogenation of the corresponding hydrazonoyl chlorides in the presence of triethylamine). The new products were tested for antiinflammatory, analgesic, and ulcerogenic score activities comparable to Indomethacin. Compounds 3i–l showed significant activity compared to Indomethacin.