Abstract
Various 2-mercapto-4-substituted-5-imidazolecarboxylates (5) were synthesized by the reaction of C-acylamino acid methyl esters (4) with potassium thiocyanate. Hydrolysis followed by decarboxylation of the imidazole carboxylates (5) gave 2-mercapto-4-substituted imidazoles (8) in good yields. Furthermore, the imidazoles (8) were also directly obtained by the reaction of aminoketones (9) with potassium thiocyanate. These compounds (8) exhibited antiinflammatory activities against carrageenan-induced rat paw edema. Among the compounds tested, 2-mercapto-4-(3-thienyl) imidazole (8r) showed the best therapeutic index value, giving a value comparable to that of mefenamic acid.
