Studies on epimeric D-xylo-and D-lyxo-tetritol-1-yl-2-phenyl-2H-1,2,3-triazoles.: Synthesis and anomeric configuration of 4-(α- and β-D-threofuranosyl)-2-phenyl-2H-1,2,3-triazole C-nucleoside analogs

Treatment of 4-(D-xylo-tetritol-1-yl-2-phenyl-2H-1,2,3-triazole (1) with one mole equivalent of tosyl chloride in pyridine solution, afforded the C-nucleoside analog; 4-(beta-D-threofuranosyl)-2-phenyl-2H-1,2,3-triazole (2) in 55% yield as well as the byproduct 4-(4-chloro-4-deoxy-D-xylo-tetritol-1-yl)-2-phenyl-2H-1,2,3-triazole (4). Treatment of the epimeric 4-(D-lyxo-tetritol-1-yl)-2-phenyl-2H-1,2,3-triazole (6) with tosyl chloride in pyridine solution afforded the anomeric C-nucleoside analog;4-(alpha-D-threofuranosyl)-2-phenyl-2H-1,2,3-triazole (7) in 29% yield, as well as the byproduct 4-(4-chloro-4-deoxy-D-lyxo-tetritol-1-yl)-2-phenyl-2H-1,2,3-triazole (9). Similar treatment of 1 and 6 with trifluoromethanesulfonyl chloride in pyridine solution afforded 2 and 7, respectively. The structure and anomeric configuration of these compounds were determined by acetylation, NMR, NOE, and circular dichroism spectroscopy, as well as mass spectrometry.