Trifluoroacetic acid → 3-[4-[4-(1,2,3,4-Tetrahydroisoquinolin-7-yloxymethyl)piperidin-1-yl]pyridin-3-yl]-2-propenoic acid ethyl ester

To a solution of 3-[4-[4-(2-tert-butoxycarbonyl-1,2,3,4-tetrahydroisoquinolin-7-yloxymethyl)piperidin-1-yl]pyridin-3-yl]-2-propenoic acid ethyl ester (100 mg) in chloroform (1.5 ml) was added trifluoroacetic acid (0.45 ml), and the mixture was stirred at room temperature for 1 hour. After completion of the reaction, the solvent was evaporated. To the obtained residue was added aqueous sodium hydrogencarbonate solution and the mixture was extracted with ethyl acetate and washed successively with water and saturated brine. The organic layer was dried over anhydrous sodium sulfate and the solvent was evaporated. The residue was dried under reduced pressure to give the title compound (70 mg).