1: methyl 3-O-tert-butyldimethylsilyl-4,6-O-p-methoxybenzylidene-2-deoxy-2-trifluoroacetamido-β-D-glucopyranoside With sodium hydroxide in methanol; water 7 h; Heating; 2: acetic anhydride in methanol T=0°C; 0.5 h; 3: With acetic acid in tetrahydrofuran; water T=45°C; 1.5 h;