Nitric Acid → 8-Nitro-1,2,3,6-tetrahydroazepino[4,5-b]indole-5-carboxylic acid ethyl ester
Reaction equation
[N+:1]([O-:4])(O)=[O:2].[CH2:5]1[C:18]2[C:17]3[CH:16]=[CH:15][CH:14]=[CH:13][C:12]=3[NH:11][C:10]=2[C:9]([C:19]([O:21][CH2:22][CH3:23])=[O:20])=[CH:8][NH:7][CH2:6]1.[OH-].[NH4+]>C(O)(=O)C>[CH2:22]([O:21][C:19]([C:9]1[C:10]2[NH:11][C:12]3[CH:13]=[C:14]([N+:1]([O-:4])=[O:2])[CH:15]=[CH:16][C:17]=3[C:18]=2[CH2:5][CH2:6][NH:7][CH:8]=1)=[O:20])[CH3:23]Participants
Procedure
A solution of nitric acid (90%, 50 μL, 1 mmol) in acetic acid (3 mL) was added dropwise to a stirred solution of ethyl 1,2,3,6-tetrahydroazepino[4,5-b]indole-5-carboxylate (256 mg, 1 mmol) in acetic acid (5 mL) at 10° C. The mixture was allowed to warm to ambient temperature and stirred for another 1.5 hours, then poured into a mixture of ammonium hydroxide and ice and extracted with DCM. The combined extracts was washed with brine, dried with sodium sulfate, and evaporated in vacuo. The crude product was purified by chromatography on silica gel eluting with hexane-EtOAc (75:25) to give 8-nitro-1,2,3,6-tetrahydroazepino[4,5-b]indole-5-carboxylic acid ethyl ester (25 mg); 1H-NMR (CDCl3): δ 11.52 (1H, s), 8.78 (1H, d), 8.43 (1H, m), 7.92 (1H, d), 7.82 (1H, dd), 7.46 (1H, d), 4.24 (2H, q), 3.52 (2H, m), 3.07 (2H, m), 1.27 (3H, t); MS (ES): 301 (MH+).
Workup
- extractionextracted with DCM
- washThe combined extracts was washed with brine
- dry with materialdried with sodium sulfate
- customevaporated in vacuo
- customThe crude product was purified by chromatography on silica gel eluting with hexane-EtOAc (75:25)
Sources & evidence
- ORD record
- ord-b2f008b2e465475e8b499cef548de8f9
- Source dataset
- uspto-grants-2013_09
- Patent number
- US08524704B2
Reaction notes
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