A method for synthesizing 1-thio-β-D-glucose tetraacetate comprising the steps of (1) dissolving a thioacetyl-protected sugar, a thiol and a weak base in an organic solvent to configure a mixed solution. This was done as follows: 2,3,4,6-tetra-O-acetyl-1-S-acetyl-β-D-galactopyranose (600 mg, 1.48 mmol) was used as the thioacetyl-protected sugar, L-cysteine methyl ester hydrochloride (254 mg, 1.48 mmol) was used as the thiol, triethylamine (0.2 mL, 1.48 mmol) was used as the weak base, dimethylformamide ( 14.8 mL) was the solvent. The molar ratio of thioacetyl-protected sugar to thiol was 1:1, and the molar ratio of thioacetyl-protected sugar to weak base was also 1:1, and the concentration of thioacetyl-protected sugar was 0.1 M. (2) The mixed solution obtained in step (1) was stirred and reacted for 1.5 h at room temperature. After completion of the reaction, extraction and purification operations were carried out: 50 mL of water was added to the reaction mixture, extracted with toluene (3 x 100 mL), the organic phases were combined, the organic phase was washed with saturated saline, followed by drying with anhydrous sodium sulfate, and finally concentrated under reduced pressure to obtain 517 mg of 2,3,4,6-tetra-O-acetyl-β-D-galactopyranosylthiol in 96% yield.
