Ethyl Acetate → 1,2,3,3a,8,8a-Hexahydro-5-(methyloxycarbonylamino)-1,3a,8-trimethylpyrrolo[2,3-b]indole
Reaction equation
[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[N:9]([CH3:13])[CH:8]1[N:14]([CH3:17])[CH2:15][CH2:16][C:7]21[CH3:18])([O-])=O.[C:19]([O:22][CH2:23]C)(=[O:21])C>O=[Pt]=O>[CH3:23][O:22][C:19]([NH:1][C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[N:9]([CH3:13])[CH:8]1[N:14]([CH3:17])[CH2:15][CH2:16][C:7]21[CH3:18])=[O:21]Participants
Conditions
- Temperature
- 0 °C
Procedure
1,2,3,3a,8,8a-Hexahydro-5-nitro-1,3a,8-trimethylpyrrolo[2,3-b]indole (1.0 g) was dissolved in ethyl acetate (100 ml) and hydrogenated in a Parr apparatus at 45 psi using PtO2 (100 mg) as a catalyst. The reduction was complete within 2 hours. The reduction mixture was filtered directly into a nitrogen flushed flask. 4-Dimethylaminopyridine (50 mg) was added, the mixture was cooled to 0° C. and a solution of dimethylpyrocarbonate (0.54 g) in ethyl acetate (50 ml) was added over a period of 1 hour. The mixture was concentrated and purified by flash chromatography on silica gel (eluting with 15% MeOH/EtOAc). The pure fractions were concentrated to give 1,2,3,3a,8,8a-hexahydro-5-(methyloxycarbonylamino)-1,3a,8-trimethylpyrrolo[2,3-b]indole (0.4 g) and the oxalate salt was prepared by dissolving the free base in ether and a minimal amount of methanol and adding a solution of oxalic acid in ether.
Workup
- filtrationThe reduction mixture was filtered directly into a nitrogen flushed flask
- addition4-Dimethylaminopyridine (50 mg) was added
- additiona solution of dimethylpyrocarbonate (0.54 g) in ethyl acetate (50 ml) was added over a period of 1 hour
- concentrationThe mixture was concentrated
- custompurified by flash chromatography on silica gel (eluting with 15% MeOH/EtOAc)
- concentrationThe pure fractions were concentrated
Sources & evidence
- ORD record
- ord-3e048bee2c264126a06fe179699f43fa
- Source dataset
- uspto-grants-1991_01
- Patent number
- US04983616
Reaction notes
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