Ethyl Acetate → 5-Ethoxycarbonylamino-1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethylpyrrolo[2,3-b]indole

HRID 703537Notes

Reaction equation

HRID 703537 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][CH3:24])(=[O:21])C>O=[Pt]=O>[CH2:23]([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])[CH3:24]

Participants

4

Reactant 2

HCID 8857Ethyl AcetateHCID 199089181,2,3,3a,8,8a-Hexahydro-5-nitro-1,3a,8-trimethylpyrrolo[2,3-b]indole

Product 1

HCID 199089275-Ethoxycarbonylamino-1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethylpyrrolo[2,3-b]indole

Reagents, catalysts & solvents 1

HCID 345198Adams' catalystCatalyst

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) and triethylamine (0.14 g) were added, the mixture was cooled to 0° C. and a solution of ethylchloroformate (0.44 g) in ethyl acetate (70 ml) was added over a period of 1.5 hours. The mixture was washed with water (2×100 ml), dried (Na2SO4), concentrated and purified by flash chromatography on silica gel (eluting with 15% MeOH/EtOAc). The pure fractions were concentrated to give 5-ethoxycarbonylamino-1,2,3,3a,8,8a-hexahydro-1,3a,8-trimethylpyrrolo[2,3-b]indole (0.6 g). The oxalate salt was prepared by dissolving the free base in ether (200 ml) and a minimum amount of MeOH (20 ml) and adding a solution of oxalic acid in ether.

Workup

  1. filtrationThe reduction mixture was filtered directly into a nitrogen flushed flask
  2. addition4-Dimethylaminopyridine (50 mg) and triethylamine (0.14 g) were added
  3. additiona solution of ethylchloroformate (0.44 g) in ethyl acetate (70 ml) was added over a period of 1.5 hours
  4. washThe mixture was washed with water (2×100 ml)
  5. dry with materialdried (Na2SO4)
  6. concentrationconcentrated
  7. custompurified by flash chromatography on silica gel (eluting with 15% MeOH/EtOAc)
  8. concentrationThe pure fractions were concentrated

Sources & evidence

ORD record
ord-185cd1f932db4391bd7c46d9aab46b23
Source dataset
uspto-grants-1991_01
Patent number
US04983616

Reaction notes

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