3482-14-2

32999-37-4

Under the condition of ice-water bath, isoquinolin-8-ol (2.9 g, 20 mmol) was dissolved in acetic acid (15 mL) and sodium borohydride (3.78 g, 100 mmol) was added slowly. After the addition was completed, the reaction mixture was gradually warmed up to room temperature and the reaction was continued with stirring for 1 hour. Upon completion of the reaction, the reaction solution was slowly poured into ice (50 g) to quench the reaction, followed by extraction with ethyl acetate (100 mL × 2). The organic phases were combined, dried with anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent. Finally, the target product 8-hydroxy-1,2,3,4-tetrahydroisoquinoline (2.12 g, 71% yield) was purified by silica gel column chromatography (eluent ratio of petroleum ether: ethyl acetate = 5:1).