Esculin (1.0 g), benzyl chloride (1.0 g), potassium carbonate (0.7 g), catalytic amounts of 18-crown-6-ether and potassium iodide, and dimethylformamide (40 ml) were placed in an eggplant-shaped flask (100 ml). The mixture was reacted while stirred at 60° C. for 8 hours. The reaction mixture was concentrated under reduced pressure and the residue was poured into ice water. The precipitated crystals were filtered out and recrystallized from methanol to obtain 7-benzyloxy-6-D-glucopyranosyloxycoumarin (VIII-2) (melting point=184° to 186° C., mass spectrum (M+)=430, yield=86.4%).
