2,3-O-???????-D-???-1,4-??

??????? L(+)-Gulonic acid gamma-lactone 2,3,5-Tri-O-benzyl-D-ribonolactone 2-C-Methyl-D-ribono-1,4-lactone 2,3,5-Tri-O-benzoyl-2-C-methyl-D-ribonic acid-1,4-lactone 2,3-O-Isopropylidene-D-ribonic gamma-lactone Aceglatone D-Glucurono-6,3-lactone acetonide D-MANNONO-1,4-LACTONE 2,3:5,6-Di-O-isopropylidene-L-gulonolactone ALPHA,BETA-GLUCOOCTANOIC GAMMA-LACTONE 6-CHLORO-6-DEOXY-D-MANNONOLACTONE 2C-Hydroxymethyl-2,3:5,6-di-O-isopropylidene-D-mannono-1,4-lactone 5,6-O-Isopropylidene-L-gulonic acid-1,4-lactone D-LYXONO-1,4-LACTONE 2C-Hydroxymethyl-2,3:5,6-di-O-isopropylidene-L-gulono-1,4-lactone 2,3:5,6-Di-O-isopropylidene-D-mannono-1,4-lactone 5-O-ACETYL-D-RIBO-1,4-LACTONE