Ethyl 5-nitro-1H-indole-2-carboxylate → Ethyl 5-amino-1H-indole-2-carboxylate

HRID 2054714Notes

Reaction equation

HRID 2054714 reaction equation
[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][C:8]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[CH:7]2)([O-])=O>[Pd].CO.C1COCC1>[NH2:1][C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][C:8]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[CH:7]2

Participants

4

Reactant 1

HCID 280312Ethyl 5-nitro-1H-indole-2-carboxylate

Product 1

HCID 10726872Ethyl 5-amino-1H-indole-2-carboxylateYield 94%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 21899815MeOH tetrahydrofuranSolvent

Procedure

A 500 mL Par hydrogenation bottle was charged with ethyl 5-nitroindole-2-carboxylate (8) (5.0 g, 21.36 mmol), 10% Pd/C (0.3 g), methanol/THF (150 mL, 1:4 v/v), and was purged with hydrogen. The reaction mixture was shaken with 40 psi H2 overnight. The catalyst was removed by filtration and the solvent was evaporated to give 4.10 g (94% yield) of the title compound 18 as a brown solid. 1H NMR (CDCl3), 8.77 (s, 1H), 7.26 (s, 1H), 7.23 (t, 1H, J=0.8 Hz), 7.21 (d, 1H, J=0.7 Hz), 7.03 (dd, 1H, J=0.7, 1.5 Hz), 6.93 (dd, 1H, J=0.7, 1.6 Hz), 6.80 (dd, 1H, J=2.2, 8.6 Hz), 4.38 (dd, 2H, J=7.2, 14.3 Hz), 1.40 (t, 3H, J=7.2 Hz); 13C NMR (CDCl3) 162.02, 140.30, 138.14, 131.87, 128.45, 127.77, 117.12, 112.50, 107.36, 105.86, 60.87, 14.41. This product is unstable and therefor it was used immediately in next step.

Workup

  1. customwas purged with hydrogen
  2. customThe catalyst was removed by filtration
  3. customthe solvent was evaporated

Sources & evidence

ORD record
ord-7cb4d5d3337a4ee7ad4dfdaae3451f36
Source dataset
uspto-grants-2008_02
Patent number
US07329760B2

Reaction notes

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