Hydrochloric Acid → 6-Bromo-2,3,4,5-tetrahydro-1H-1-benzazepine

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Reaction Steps

To a solution of (E)-5-bromo-3,4-dihydronaphthalen-1(2H)-one oxime (1.41 g, 5.87 mmol) in DCM (20 mL) at −10° C. under nitrogen was slowly added a solution of 1.0 M DIBAL-H in hexane (35.2 mL, 35.2 mmol). Upon completion of addition, the reaction mixture was stirred at room temperature for 2 h. After this time, the reaction mixture was cooled to 0° C. and then sodium fluoride (7.40 g, 176 mmol) and water (3.0 mL) were slowly added. The resulting mixture was stirred at 0° C. for 30 min and then CELITE® was added. The mixture was filtered and rinsed with DCM (100 mL). The filtrate was dried over anhydrous Na2SO4, filtered, and concentrated to provide the crude product. The crude product was converted to the HCl salt with aqueous 1.0 N HCl (3.0 mL) and then purified by preparative HPLC (PHENOMENEX® Axia Luna 5μ C18 30×100 mm; 10 min gradient from 80% A:20% B to 0% A:100% B and 5 min 100% B (A=90% H2O/10% MeOH+0.1% TFA); (B=90% MeOH/10% H2O+0.1% TFA); detection at 220 nm). The purified product was free based with a solution of saturated sodium bicarbonate (15 mL) and was then extracted with ethyl acetate (20 mL). The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated to afford the title compound (612 mg, 45% yield). LCMS, [M+Na]+=236.0. 1H NMR (400 MHz, MeOD) δ 7.12 (dd, J=7.8, 1.4 Hz, 1H), 6.88 (t, J=7.8 Hz, 1H), 6.83 (dd, J=7.8, 1.4 Hz, 1H), 3.08-3.02 (m, 4H), 1.86-1.79 (m, 2H), 1.69-1.62 (m, 2H).

Provenance & Evidence