Patent ID: 7622563

Claim:
A method for preparing a glycoside represented by formula (3): wherein: R1 represents a C 1 -C 10 straight or branched alkyl; any one of R2, R3 and R4 represents a hydroxyl; each of the remaining two of R2, R3, and R4 represent a residue formed by reacting glucose pentaacetate with a hydroxyl group of an alkyl gallate; and the method comprises the step of: reacting an alkyl gallate having a C 1 -C 10 straight or branched alkyl with glucose pentaacetate in the presence of an organic solvent and an acid catalyst at 30° C. to 60° C. while removing from the reaction system organic solvent and acetic acid formed during the reaction, thereby maintaining the concentration of the acetic acid in the reaction system at 1.0 percent by weight or less during the reaction; wherein a distillate comprising said acetic acid and organic solvent both removed from the reaction system is distilled off at a rate of 20 to 500 g/hr relative to one mol of the alkyl gallate having C 1 -C 10 straight or branched alkyl; and wherein an amount of the substrate concentration is 5 percent to 50 percent by weight.