Methanol → 1-Aminomethyl-5,6-dihydroxy-3-phenyl-3,4-dihydronaphthalene Hydrobromide

Temperature

-78 °C

1-Aminomethyl-5,6-dimethoxy-3-phenyl-3,4-dihydronaphthalene hydrochloride (6.0 g, 20.2 mmol), from Step 2, was suspended in 200 mL of methylene chloride and boron tribromide (90.5 mL of 1M solution of BBr3 in methylene chloride) was added dropwise while the reaction mixture was being cooled (to -78° C.) in a dry ice/acetone bath. The reaction mixture was warmed to 0° C. and stirred for 0.5 h, then again cooled to -78° C. in a dry ice/acetone bath. Methanol (50 mL) was added dropwise to the reaction mixture, which was allowed to warm to ambient temperature then concentrated in vacuo. Methanol was added to the residue and the solution was reconcentrated. This residue was dissolved in a small amount of methanol and the methanol solution was added to 700 mL of diethyl ether. The precipitate which formed was filtered, washed with diethyl ether and recrystallized from methanol/ether to give 2.5 g (45% yield) of the title compound, m.p. 223°-225° C. 1H NMR (d6 -DMSO) δ: 2.68 (dd, 1H), 3.09 (dd, 1H), 3.6-3.7 (m, 1H), 3.9 (s, 2H), 5.97 (d, 1H), 6.69 (m, 2H), 7.2-7.35 (m, 5H), 8.1 (br s, 3H), 8.4 (s, 1H), 9.5 (s, 1H).

1. temperatureThe reaction mixture was warmed to 0° C.
2. temperatureagain cooled to -78° C. in a dry ice/acetone bath
3. temperatureto warm to ambient temperature
4. concentrationthen concentrated in vacuo
5. additionMethanol was added to the residue
6. dissolutionThis residue was dissolved in a small amount of methanol
7. additionthe methanol solution was added to 700 mL of diethyl ether
8. customThe precipitate which formed
9. filtrationwas filtered
10. washwashed with diethyl ether
11. customrecrystallized from methanol/ether

ORD record

ord-ae28b7eab5bc4a70853ee2e28a234ca6

Source dataset

uspto-grants-1997_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05621133