Synthesis of 1-(4-thio-beta-D-ribofuranosyl)-1,2,4-triazole-3-carboxamide

The synthesis of 1-(4-thio-beta-D-ribofuranosyl)-1,2,4-triazole-3-carboxamide (3) is described. The acid-catalyzed fusion procedure with 3-cyano-1,2,4-triazole and 1,2,3,5-tetra-O-acetyl-4-thio-D-ribofuranose provided 3-cyano-1-(2,3,5-tri-O-acetyl-4-thio-beta-D-ribofuranosyl-1,2,4-triazole (2) which was converted with NH4OH to 3. In contrast to 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (1), the 4'-thio nucleoside 3 did not exhibt significant antiviral activity in vitro.