Stannous Chloride → Ethyl 6-amino-1H-indole-4-carboxylate

HRID 503403Notes

Reaction equation

HRID 503403 reaction equation
CN(C)/[CH:3]=[CH:4]/[C:5]1[C:15]([N+:16]([O-])=O)=[CH:14][C:13]([N+:19]([O-])=O)=[CH:12][C:6]=1[C:7]([O:9][CH2:10][CH3:11])=[O:8].Cl[Sn]Cl>C(O)C>[NH2:19][C:13]1[CH:12]=[C:6]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[C:5]2[CH:4]=[CH:3][NH:16][C:15]=2[CH:14]=1

Participants

4

Reactant 2

HCID 24479Stannous ChlorideHCID 57470203HCID 57470203, compound

Product 1

HCID 53435938Ethyl 6-amino-1H-indole-4-carboxylateYield 40%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of (E)-ethyl 2-(2-(dimethylamino)vinyl)-3,5-dinitrobenzoate (11 g, 0.037 mol) and SnCl2 (83 g, 0.37 mol) in ethanol was heated at reflux for 4 h. The mixture was concentrated to dryness and the residue was poured into water and basified using sat. aq. Na2CO3 to pH 8. The precipitated solid was filtered and the filtrate was extracted with ethyl acetate (3×100 mL). The combined extracts were washed with water (2×100 mL) and brine (150 mL), dried over Na2SO4, and concentrated to dryness. The residue was purified by column on silica gel to give ethyl 6-amino-1H-indole-4-carboxylate (3.0 g, 40%). 1HNMR (DMSO-d6) δ 10.76 (br s, 1H), 7.11-7.14 (m, 2H), 6.81-6.82 (m, 1H), 6.67-6.68 (m, 1H), 4.94 (br s, 2H), 4.32-4.25 (q, J=7.2 Hz, 2H), 1.35-1.31 (t, J=7.2, 3H); MS (ESI) m/e (M+H+) 205.0.

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 4 h
  3. concentrationThe mixture was concentrated to dryness
  4. additionthe residue was poured into water
  5. filtrationThe precipitated solid was filtered
  6. extractionthe filtrate was extracted with ethyl acetate (3×100 mL)
  7. washThe combined extracts were washed with water (2×100 mL) and brine (150 mL)
  8. dry with materialdried over Na2SO4
  9. concentrationconcentrated to dryness
  10. customThe residue was purified by column on silica gel

Sources & evidence

ORD record
ord-c4ef544a33074c39b97f8fed314e83cf
Source dataset
uspto-grants-2010_08
Patent number
US07776905B2

Reaction notes

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