NaBH4 (3.46 g, 91.51 mmol) was slowly added to a solution of acetic acid (90 mL) containing 6-bromoisoquinoline (4.76 g, 22.88 mmol) at room temperature with continuous stirring for 1.5 h. The reaction was carried out using a mixture of ethyl acetate and THF. Upon completion of the reaction, water was added to the mixture and the pH was adjusted to 8 with an aqueous solution of 8 N sodium hydroxide.Subsequently, the reaction mixture was extracted three times using a solvent mixture of ethyl acetate/THF (3:1, v/v). The organic layers were combined, washed with water and dried with magnesium sulfate. After removal of the solvent by evaporation under reduced pressure, the residue was purified by silica gel column chromatography (using NH silica gel, solvent gradient: 20%→90% ethyl acetate/hexanes) to afford the target compound, 6-bromo-1,2,3,4-tetrahydroisoquinoline (3.26 g, 15.37 mmol, 67.2% yield), as a colorless oil.1H NMR (300 MHz, CDCl3 ) data were as follows: δ 1.63 (1H, s), 2.77 (2H, t, J = 6.0 Hz), 3.11 (2H, t, J = 5.9 Hz), 3.95 (2H, s), 6.85-6.90 (1H, m), 7.21-7.26 (2H, m).
