Trichloroacetic Acid → 2,3,4,5-tetrahydro-1H-2-benzazepin-3-one

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Reaction Steps

At 65° C., β-tetralone (5 g, 34.2 mmol) was dissolved in trichloroacetic acid (56 g, 0.34 mol). Sodium azide (3.3 g, 50 mmol, 1.5 eq.) was then added in portions. The mixture was stirred for 9 h and then water (400 mL) was added. The mixture was extracted with dichloromethane (3×200 mL), dried with sodium sulfate, filtered and concentrated in vacuo. The crude mixture was then recrystallized from dichloromethane/hexane to give 1,2,4,5-tetrahydro-benzo[c]azepin-3-one (4 g): 1H NMR (300 MHz, CDCl3) δ 7.2 (m, 4H), 4.37 (d, 1H), 3.1 (m, 2H), 2.8 (m, 2H) and 1,3,4,5-tetrahydro-benzo[d]azepin-2-one (1.5 g): 1H NMR (300 MHz, CDCl3) δ 7.2 (m, 4H), 3.84 (s, 2H), 3.6 (m, 2H), 3.12 (t, 2H).

Provenance & Evidence