SYNTHESIS AND ANTIVIRAL EVALUATION OF SOME NOVEL [1,2,4]TRIAZOLO[4,3-B][1,2,4]TRIAZOLE NUCLEOSIDE ANALOGS

Ribosylation of 3-amino-5H-[1,2,4]triazolo[4,3-b][1,2,4]triazole (1) with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose and stannic chloride resulted in the following protected nucleoside analogs: 3-amino-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)[1,2,4]triazolo[4,3-b][1,2,4]triazole (4), 3-amino-1-(2,3,5-tri-O-benzoyl-alpha-D-ribofuranosyl)[1,2,4]triazolo[4,3-b][1,2,4]triazole (5), 3-imino-2H-2-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)[1,2,4]triazolo[4,3-b][1,2,4]triazolo[4,3-b][1,2,4]triazole (6), and 3-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)amino-5H-[1,2,4]triazolo[4,3-b][1,2,4]triazole (7). Compounds 4-6 were deprotected to 3-amino-1-beta-D-ribofuranosyl[1,2,4]triazo[4,3-b][1,2,4],triazole (3), 3-amino-1-alpha-D-ribofuranosyl[1,2,4]triazolo[4,5-b][1,2,4]triazole (8), and 3-imino-2H-2-beta-D-ribofuranosyl[1,2,4]triazolo[4,3-b][1,2,4]triazole (9), while 7 could not be deprotected without decomposition. Compounds 1, 4, 6, 7, and 9 were screened and found to have no antiviral activity.