Methanol → 8-Bromo-2,3,4,5-tetrahydro-1H-benzo[b]azepine

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Reaction Steps

Borane tetrahydrofuran complex (1 M solution in tetrahydrofuran, 21 mL, 21 mmol) was added to a solution of 8-bromo-1,3,4,5-tetrahydro-benzo[b]azepin-2-one (prepared from 7-bromo-3,4-dihydro-2H-naphthalen-1-one in analogy with the general procedure described in J Chem. Soc. (C) 1969, 183; 1.00 g, 4.17 mmol) in tetrahydrofuran, and the solution was heated at reflux for 2 h. After cooling, methanol (21 mL) was added, and volatile material was removed by distillation. The residue was taken up in 5% ethanolic sulfuric acid solution (12 mL) and heated at reflux for 2 h, then basified to pH 10 by addition of 2 M aq. sodium hydroxide solution and partitioned between water and ethyl acetate. The organic layer was dried (MgSO4) and evaporated. Chromatography (SiO2, heptane-ethyl acetate 2:1) yielded 8-bromo-2,3,4,5-tetrahydro-1H-benzo[b]azepine (865 mg, 92%). White solid, MS (ISP) m/e 226.1 (M+H).

Provenance & Evidence