article unclassified drug proton nuclear magnetic resonance 4 carbon nuclear magnetic resonance 3 chemical structure 3 heterocyclic compound 3 antiviral activity 2 cyclization 2 nucleoside derivative 2 synthesis 2 1,2 o isopropylidene alpha dextro xylopentadialdo 1,4 furanose 1 1,2 o isopropylidene alpha levo furanosyl derivative 1 1,2:3:4 di o isopropylidene alpha dextro galacto 1,6 hexadialdo 1,5 pyranose derivative 1 2 amino 5 [5' (1',2':3',4' di o isopropylidene beta levo arabinopyranosyl)] 1,3,4 thiadiazole 1 2 amino 5 [5' (alpha levo arabinopyranosyl)] 1,3,4 thiadiazole 1 2 amino 5 [5' (beta levo arabinopyranosyl)] 1,3,4 thiadiazole 1 2 methyl 5 [5' (1',2':3',4' di o isopropylidene beta levo arabinopyranosyl)] 1,3,4 oxadiazole 1 2 phenyl 5 [5' (1',2':3',4' di o isopropylidene beta levo arabinopyranosyl)] 1,3,4 oxadiazole 1 2 phenyl 5 [5' (alpha levo arabinofuranosyl)] 1,3,4 oxadiazole 1 2 phenyl 5 [5' (alpha levo arabinopyranosyl)] 1,3,4 oxadiazole 1 2 phenyl 5 [5' (beta levo arabinofuranosyl)] 1,3,4 oxadiazole 1 2 phenyl 5 [5' (beta levo arabinopyranosyl)] 1,3,4 oxadiazole 1 2,2' diacetamido 4,4' di n acetyl 5' (1 deoxy 2,3,4 tri o acetyl dextro erythritol 1 yl) 5,5' bis(1,3,4 thiadiazoline) 1 3 deoxy D erythro hexos 2 ulose 1,2 bis(thiosemicarbazone) 1 3 deoxy dextro erythro hexos 2 ulose 1,2 bis(thiosemicarbazone) 1 3-deoxy-D-erythro-hexos-2-ulose-1,2-bis(thiosemicarbazone) 1 5 [5' (1',2':3',4' di o isopropylidene beta levo arabinopyranosyl)]tetrazole 1 5 [5' (1',2':3',4' di o isopropylidene beta levo arabinopyranosyl]tetrazole 1 5 [5' (alpha levo arabinopyranosyl)]tetrazole 1 5 [5' (beta levo arabinopyranosyl)]tetrazole 1