Methanol → [1R, 3S]1-aminomethyl-3-cyclohexyl-5,6-dihydroxy-1,2,3,4-tetrahydronaphthalene hydrobromide

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Reaction Steps

[1R,3S]1-Aminomethyl-3-cyclohexyl-5,6-dimethoxy-1,2,3,4-tetrahydronaphthalene hydrochloride (0.7 g, 2.3 mmol), from Step 1, was suspended in 20 mL of methylene chloride at -78° C. Boron tribromide (9.7 mL of a 1M solution in methylene chloride, 9.7 mmol) was added and the reaction mixture was allowed to warm to ambient temperature. After stirring at ambient temperature for 1 h, the reaction mixture was cooled to -78° C. and 10 mL of methanol was added. The reaction mixture was again allowed to warm to ambient temperature and stirred at ambient temperature for 1 h. The solvent was removed in vacuo and methanol was added to the residue. The methanol solution was concentrated and the residue dissolved in a minimal amount of methanol and added dropwise to a large excess of diethyl ether. The precipitate was filtered and recrystallized from ethanol/diethyl ether to give 0.48 g (65% yield) of [1R, 3S]1-aminomethyl-3-cyclohexyl-5,6-dihydroxy-1,2,3,4-tetrahydronaphthalene hydrobromide, m.p. 203°-204° C.; 1H NMR (d6 -DMSO) δ: 0.9-1.5. (m, 8H), 1.6-1.9 (m, 5H), 2.0-2.1 (m, 2H), 2.7-3.0 (m, 3H), 3.3-3.4 (m, 1H), 6.5-6.7 (m, 2H).

Provenance & Evidence