Reactions of Ethyl 5-Methyl-4-(1,2,3-thiadiazol-4-yl)furan-2-carboxylate with Selected Bases

The reactions of 5-methyl-4-(1,2,3-thiadiazol-4-yl)furan-2-carboxylic acid ethyl ester with some bases have been studied. The opening of 1,2,3-thiadiazole ring under the action of potassium tert-butylate in tetrahydrofuran in the presence of methyl iodide has led to the corresponding 4-methylsulfanylethynylfuran derivative. Under the action of potassium carbonate in DMF with an excess of primary amines or morpholine, the starting thiadiazole has formed the corresponding thioamides of furylacetic acid. The reaction of ethyl 5-methyl-4-(1,2,3-thiadiazol-4-yl)furan-2-carboxylate with hydrazine hydrate has led to hydrazinolysis of the ester group without cleavage of the 1,2,3-thiadiazole ring.