A method of utilizing a crystalline mother liquor of 2-hydroxy-1,3,5-tri-O-benzoyl--D-ribofuranose, by reacting with acetic anhydride to prepare 2-hydroxy-1,3,5-tri-O-benzoyl--D-ribofuranose and its isomer 1-hydroxy-2,3,5-tri-O-benzoyl-D-ribofuranose, contained in a crystalline mother liquor, as 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose ,5-tri-O-benzoyl--D-ribofuranose (1-acetyl-tri-benzyloxy-robose) with the following steps:
(1) concentrating dry the dichloromethane-hexane crystallization mother liquor of 2-hydroxy-1,3,5-tri-O-benzoyl--D-ribofuranose to obtain a concentrate;
(2) dissolve the concentrate with solvent, add acetic anhydride, add concentrated sulfuric acid after cooling, keep warm and stir the reaction, add water at the end of the reaction, stir at room temperature for 2~3 hours, filter to get the crude product;
(3) Dissolve the crude product with ethanol, add silica gel, activated carbon holding and stirring, hot filtration, filtrate crystallization, filtration, to get 1-O-acetyl-2,3,5-tri-O-benzoyl--D-ribofuranose (1-Acetyl-tri-benzyloxy-Robose).
