Hydrochloric Acid → 6-Chloro-2,3,4,9-tetrahydro-1H-carbazol-1-amine

HRID 28672Notes

Reaction equation

[Cl:1][C:2]1[CH:3]=[C:4]2[C:12](=[CH:13][CH:14]=1)[NH:11][C:10]1[C:9](=O)[CH2:8][CH2:7][CH2:6][C:5]2=1.C([O-])(=O)C.[NH4+].C([BH3-])#[N:22].[Na+].Cl>CO>[Cl:1][C:2]1[CH:3]=[C:4]2[C:12](=[CH:13][CH:14]=1)[NH:11][C:10]1[CH:9]([NH2:22])[CH2:8][CH2:7][CH2:6][C:5]2=1

Participants

Conditions

Temperature: 60 °C

Procedure

To a solution of 6-chloro-2,3,4,9-tetrahydro-1H-carbazol-1-one (500 mg, 2.3 mmol) and ammonium acetate (1.8 g, 23 mmol) in methanol (9 mL) was added sodium cyanoborohydride (720 mg, 11.5 mmol). After heating at 60° C. for 15 hours, the mixture was cooled and treated with concentrated hydrochloric acid until pH=1. The organics were removed under reduced pressure and the resulting precipitate was collected by filtration, dissolved in ethyl acetate and methanol, and washed with saturated aqueous sodium carbonate. The phases were separated and the organic phase was concentrated to yield 6-chloro-2,3,4,9-tetrahydro-1H-carbazol-1-amine (260 mg, 52% yield) as a light brown solid. 1H-NMR (DMSO-d6): δ 10.90 (s, 1H), 7.34 (m, 1H), 7.27 (d, 1H), 6.97 (dd, 1H), 3.90 (t, 1H), 2.54 (m, 2H), 2.04-1.89 (m, 2H), 1.66 (m, 1H), 1.50 (m, 1H); MS m/z 221 (M+1).

Workup

temperaturethe mixture was cooled
customThe organics were removed under reduced pressure
filtrationthe resulting precipitate was collected by filtration
dissolutiondissolved in ethyl acetate
washmethanol, and washed with saturated aqueous sodium carbonate
customThe phases were separated
concentrationthe organic phase was concentrated

Sources & evidence

ORD record: ord-c939908619474f5692457194eb3453b7
Source dataset: uspto-grants-2008_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07419997B2

Reaction notes

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