Hydrochloric Acid → 2-(3-Dimethylaminomethyl-phenyl)-1,3,4,5-tetrahydro-azepino[5,4,3-cd]indol-6-one

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Reaction Steps

The aldehyde compound 15 (346 mg, 1.19 mmol) in MeOH (40 mL) was treated with dimethyl amine (2M solution in MeOH, 7.16 mmol). The solution was cooled with an ice/water bath and treated dropwise with a solution of sodium cyanoborohydride (82 mg, 1.31 mmol) and zinc chloride (89 mg, 0.66 mmol) in MeOH (10 mL). The resulting solution was adjusted to pH=6-7 with 2M methanolic HCl. After stirring for 30 min., the reaction was quenched with conc. HCl (0.2 mL) and the methanol was removed by evaporation. The residue was diluted with water (30 mL). The solution was adjusted to pH=10-11 with KOH (s) and extracted with CH2Cl2 (30 mL×3). The organic solution was washed with water and brine, dried (Na2SO4), filtered, and concentrated. The crude product was crystallized (CH2Cl2/MeOH/hexanes) to give 2-(3-(N,N-dimethylamino)methylphenyl)-3,4,5,6-tetrahydro-1H-azepino[5,4,3-cd]indol-6-one, 332 mg (87%), as shiny yellow crystals. mp 222-225° C.; 1H NMR (300 MHz, d6-DMSO) δ 2.20 (s, 6H), 3.06 (m, 2H), 3.40 (m, 2H), 3.50 (s, 2H), 7.21 (t, 1H, J=7.7 Hz), 7.41 (br d, 1H, J=7.4 Hz), 7.50 (m, 4H), 7.69 (d, 1H, J=7.1 Hz), 8.05 (br t, 1H), 11.56 (br s, 1H); HRMS (FAB, MH+) Calcd for C20H22N3O: 320.1763, Found: for C20H22N3O: 320.1763, Found: 320.1753; Anal. (C20H21N3O.0.25 H2O) C, H, N.

Provenance & Evidence