Methanol → 1-Aminomethyl-3-cyclohexyl-5,6-dihydroxy-3,4-dihydronaphthalene hydrobromide

Temperature

-78 °C

1-Aminomethyl-3-cyclohexyl-5,6-dimethoxy-3,4-dihydronaphthalene hydrochloride (2.7 g, 8.9 mmol), from Step 2, was dissolved in 72 mL of methylene chloride and cooled to -78° C. Boron tribromide (36 mL of a 1M solution in methylene chloride) was added and the reaction mixture was warmed to 0° C. for 1 h. The reaction mixture was cooled again to -78° C. and 30 mL of methanol was added. After stirring at ambient temperature for 1 h, the reaction mixture was concentrated, diluted with methanol and reconcentrated. The residue was dissolved in methanol and the methanol solution was added dropwise to an excess amount of diethyl ether. The precipitate was filtered and recrystallized from ethanol/ether to give 2.2 g (79% yield) of the title compound, m.p. 212°-213° C.; 1H NMR (d6 -DMSO) δ: 1.0-1.4 (m, 7H), 1.55-1.9 (m, 6H), 2.05-2.15 (m, 1H), 2.47 (dd, 1H), 2.74 (dd, 1H), 5.83 (d, 1H), 6.60 (m, 2H).

1. temperaturethe reaction mixture was warmed to 0° C. for 1 h
2. temperatureThe reaction mixture was cooled again to -78° C.
3. concentrationthe reaction mixture was concentrated
4. additiondiluted with methanol
5. dissolutionThe residue was dissolved in methanol
6. additionthe methanol solution was added dropwise to an excess amount of diethyl ether
7. filtrationThe precipitate was filtered
8. customrecrystallized from ethanol/ether

ORD record

ord-136c8c7bf4384a468ad49bdfb8db7481

Source dataset

uspto-grants-1997_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05621133