To a solution of ethyl[5-methoxy-2-(6-methoxy-1,2,3,4-tetrahydronaphthalen-2-yl)phenyl]amine (100 mg) in 1,4-dioxane (3 ml) were sequentially added N,N-diisopropylethylamine (0.34 ml) and benzoyl chloride (0.05 ml), and the solution was stirred for 1 hour at 100° C. The solution was let to cool down, then a saturated aqueous solution of sodium bicarbonate was added thereto, the solution was extracted with ethyl acetate, then sequentially washed with an aqueous solution of 10% citric acid and brine, dried over anhydrous magnesium sulfate, and then the solvent was evaporated in vacuo. The residue was purified by silica gel column chromatography (hexane-ethyl acetate-tetrahydrofuran system) to provide the title compound (133 mg).
