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With sodium methylate; acetic acid; In methanol; dichloromethane; for 4.0h;pH 6.0;
3-1) tetraacetyl forsythia the glycosides were dissolved in 30 ml of a mixed solution of dichloromethane and methanol in which the ratio of methylene chloride to methanol was 1: 2 followed by sodium methoxide (0.22 mg, 0.004 mmol), sodium methoxide2, 3, 4, 6-tetra-O-acetyl-D-glucopyranosyltrichloracetic acid imide was 1: 375, followed by stirring to effect a deacylation reaction. After 4 h, a pH adjuster acetic acid,Adjust the deacylation reactionThe pH of the mixture reaches 6;In the process of the deacylation reaction in the present invention, the basicity of sodium methoxide added does not destroy the glycosidic bond and can be used as a base for the deacylation reaction, to remove the acyl protecting group, to promote the glycosylation reaction get on. The deacylation reaction time is at least 4 h, preferably 4-12 h. 3-2) was concentrated under reduced pressure using a rotary evaporator under vacuum and evaporated to remove the solvent. The silica gel was purified by column chromatography (eluent: chloroform / methanol = 8: 2) to give white solid forsythin 426 5 mg, total yield 79.8%.