SYNTHESES OF 2-DEOXY-2-FLUORO MONOSACCHARIDE AND OLIGOSACCHARIDE GLYCOSIDES FROM GLYCALS AND EVALUATION AS GLYCOSIDASE INHIBITORS

Several fluorinated oligosaccharides, including 2-deoxy-2-fluoro deriv atives of cellobiose, maltose, and maltotriose were synthesized by the action of fluorine or acetyl hypofluorite on the corresponding glycal peracetates. Temperature effects on the stereoselectivities of these reactions were examined. Addition of acetyl hypofluorite to several 2- substituted glycals in the gluco or galacto series gave 2,2-disubstitu ted arabino- or lyxo-hexose derivatives; 3,4,6-tri-O-acetyl-2-fluoro-D -glucal or the analogous galactal yielded 2-deoxy-2,2-difluoro arabino - or lyxo-hexose peracetates, whereas 2-acetoxy-3,4,6-tri-O-acetyl-D-g lucal or the analogous galactal gave 2(R)-2-acetoxy-2-fluoro-arabino- or lyxo-hexose peracetates, respectively. 2-Acetamido-3,4,6-tri-O-acet yl-D-glucal gave y-3,4,6-tri-O-acetyl-alpha-D-arabino-hexopyranosyl fl uoride. 2,4-Dinitrophenyl 2-deoxy-2-fluoro-beta-cellobioside was an in activator of the exoglucanase from Cellulomonas fimi while 2-deoxy-2-f luoro-alpha-maltosyl and alpha-maltotriosyl fluorides were slow substr ates of human pancreatic alpha-amylase and rabbit muscle glycogen debr anching enzyme, respectively.