Abstract:

Proposed in this paper is an improved Tietze＇s method to synthesize phenolic O-glycoside. In this method, anhydrousSnCl₄instead of trimethylsilyl trifluromethanesulfonate was used as the reaction accelerator, and peracetyl glycoside instead of 1-O-trimethylsilyl acetyl glycoside was used as the starting material to react with three phenolic trimethylsilyl ethers （ Ⅰ a- Ⅰ c）. Thus, three kinds of products, namely 1-O-（4-nitrophenyl）-2,3,5-tri- O-acetyl-β-D-ribofuranoside, 1-O-（ 4-acetylphenyl ） -2,3,5-tri-O-acetyl-β-D-ribofuranoside, and 1-O-（ 4-benzoyloxyphenyl）-2,3,5-tri-O-acetyl-β-D-ribofuranoside, were synthesized, with a shortened synthesis route and at low cost. Moreover, the effects of different Lewis acids, the proportion of the starting materials, the anhydrous SnCl₄dosage, and the solvents on the reaction were investigated. The results show that   anhydrous SnCl₄proves to be an optimal reaction accelerator to the synthesis when the dosage is more than the stoichiometric amount;   the suitable molar ratios of the starting materials are respectively nⅠa：nⅡ：nSnCl₄=1.0：1.4：1.5,nⅠb：nⅡ：nSnCl₄=1.0：1.1：1.4,nIc：nⅡ：nSnCl₄=1.0：1.0：1.5; and   dried diehloromethane is a suitable solvent for the reaction, while aeeto- nitrile or un-dried diehlorolnethane as solvent may produce the by-product 4-nitrophenyl acetate.

Key words: phenol, glycosylation, improvement, synthesis