Hydrogen Bromide → ethyl 6-bromo-9H-pyrido[3,4-b]indole-3-carboxylate

HRID 1757987Notes

Reaction equation

[CH2:1]([O:3][C:4]([C:6]1[N:7]=[CH:8][C:9]2[NH:10][C:11]3[C:16]([C:17]=2[CH:18]=1)=[CH:15][C:14](N)=[CH:13][CH:12]=3)=[O:5])[CH3:2].N([O-])=O.[Na+].[BrH:24]>O.[Cu]Br>[CH2:1]([O:3][C:4]([C:6]1[N:7]=[CH:8][C:9]2[NH:10][C:11]3[C:16]([C:17]=2[CH:18]=1)=[CH:15][C:14]([Br:24])=[CH:13][CH:12]=3)=[O:5])[CH3:2]

Participants

Conditions

Temperature: 80 °C

Procedure

1 mmole of 6-amino-β-carbolin-3-carboxylic acid ethyl ester is diazotized at 0° C. in 2 ml of 24% aqueous hydrobromic acid with 1 mmole of sodium nitrite in 1 ml of water. This mixture is added dropwise to a solution of 40 mg of copper (I) bromide in 1 ml of 48% aqueous hydrobromic acid at room temperature. After addition is complete, the mixture is heated to 80° C. The temperature is increased to 100° C. until nitrogen evolution has ceased. 10 ml of water is then added and filtration with suction is carried out. The residue is stirred with ammonia and filtered with suction. It is then extracted by boiling with ethanol and concentrated by evaporation. By chromatography on silica gel with an eluant comprising 9 parts of chloroform and 1 part of ethanol, 6-bromo-β-carbolin-3-carboxylic acid ethyl ester of melting point 308°-313° C. is obtained in 35% yield.

Workup

additionAfter addition
temperatureThe temperature is increased to 100° C. until nitrogen evolution
filtrationfiltration with suction
filtrationfiltered with suction
extractionIt is then extracted
concentrationconcentrated by evaporation

Sources & evidence

ORD record: ord-f4101540772540e58d2b49fcec0a9212
Source dataset: uspto-grants-1983_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04371536

Reaction notes

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