Heterocycles 39. Synthesis, characterization and evaluation of the anti-inflammatory activity of thiazolo[3,2-b][1,2,4]triazole derivatives bearing pyridin-3/4-yl moiety

A series of pyridin-3/4-yl-thiazolo[3,2-b][1,2,4]triazole derivatives (5a-g, 6a-g) were synthesised by Hantzsch condensation of 5-pyridin-3/4-yl-1,2,4-triazole-3-thiol and diverse alpha-halocarbonyl compounds. Different reaction conditions (pH, temperature, solvent) were investigated for the efficient obtention of the target compounds. Under reflux and acidic conditions, the Hantzsch condensation was a one-step reaction. At room temperature and under basic conditions, it was possible to isolate the iminothioether intermediates 3/4a-g. These intermediates were cyclized in a subsequent step by treatment with concentrated sulphuric acid. The obtained compounds were evaluated for their anti-inflammatory activity. Three synthesised pyridyl-thiazolo[3,2-b][1,2,4]triazole derivatives (6c, 6d, 6f) were found to be good anti-inflammatory agents. [GRAPHICS] .