Acetic Acid → 4-Bromo-5,6,7,8-tetrahydroisoquinolin-8-OL

Temperature

0 °C

4-Bromo-6,7-dihydroisoquinolin-8(5H)-one (2.135 g, 9.44 mmol) was suspended in MeOH (18.9 mL), cooled to 0° C. and treated with NaBH4 (357 mg, 9.44 mmol) in 5 portions over 30 min; then, the reaction was stirred for ¾ h at 0° C. (TLC after 30 min showed no more starting material). AcOH was then added dropwise until pH˜5-6 and the reaction mixture was evaporated. The residue was diluted with water and poured on aq. sat. NaHCO3-sol. followed by extraction with EtOAc (3×). The organic layers were washed once with aq. sat. NaHCO3-sol. and aq. 10% NaCl-sol., dried over Na2SO4 and concentrated in vacuo. The residue was re-dissolved in CH2Cl2, evaporated with n-pentane (3×) to around 20 ml each time, while the product precipitates; then, the solvent was decanted and the residue washed with n-pentane and dried in high vacuum to afford the title compound (1.98 g, 92%) as dark brown viscous oil. MS: 227 (M+, 1Br).

1. customthe reaction mixture was evaporated
2. additionThe residue was diluted with water
3. additionpoured on aq. sat. NaHCO3-sol
4. extractionfollowed by extraction with EtOAc (3×)
5. washThe organic layers were washed once with aq. sat. NaHCO3-sol
6. dry with material, dried over Na2SO4
7. concentrationconcentrated in vacuo
8. dissolutionThe residue was re-dissolved in CH2Cl2
9. customevaporated with n-pentane (3×) to around 20 ml each time, while the product
10. customprecipitates
11. customthen, the solvent was decanted
12. washthe residue washed with n-pentane
13. customdried in high vacuum

ORD record

ord-db24f0db5e9d4da5bd208f79b28e0016

Source dataset

uspto-grants-2015_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09133158B2