Stannous chloride dihydrate → Methyl 7-aminobenzofuran-4-carboxylate

HRID 2217370Notes

Reaction equation

HRID 2217370 reaction equation
O.O.[Sn](Cl)Cl.[CH3:6][O:7][C:8]([C:10]1[CH:11]=[CH:12][C:13]([N+:19]([O-])=O)=[C:14]2[O:18][CH:17]=[CH:16][C:15]=12)=[O:9]>C(OCC)(=O)C.C(O)C>[CH3:6][O:7][C:8]([C:10]1[CH:11]=[CH:12][C:13]([NH2:19])=[C:14]2[O:18][CH:17]=[CH:16][C:15]=12)=[O:9]

Participants

5

Reactant 2

HCID 61436Stannous chloride dihydrateHCID 20738655Methyl 7-nitrobenzofuran-4-carboxylate

Product 1

HCID 14939320Methyl 7-aminobenzofuran-4-carboxylateYield 88.1%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 8857Ethyl AcetateSolvent

Procedure

Tin (II) chloride dihydrate (15.0 g, 66.5 mmol) was added to a suspension of 7-nitro-benzofuran-4-carboxylic acid methyl ester (4.82 g, 21.8 mmol) in ethyl acetate (80 mL) and ethanol (80 mL). The reaction mixture was stirred at room temperature for four days then partitioned between ethyl acetate and saturated aqueous solution of potassium carbonate. The organic extract was washed with brine, dried (anhydrous sodium sulfate) and concentrated under reduced pressure. The residue was purified by flash column chromatography over silica gel eluting with 30% ethyl acetate in hexane give 7-amino-benzofuran-4-carboxylic acid methyl ester (3.67 g, 88%). 1H NMR (CDCl3) δ: 3.92 (s, 3H), 6.60 (d, 1H, J=8.2 Hz), 7.34 (d, 1H, J=2.1 Hz), 7.67 (d, 1H, J=2.1 Hz), 7.84 (d, 1H, J=8.2 Hz).

Workup

  1. customthen partitioned between ethyl acetate and saturated aqueous solution of potassium carbonate
  2. extractionThe organic extract
  3. washwas washed with brine
  4. dry with materialdried (anhydrous sodium sulfate)
  5. concentrationconcentrated under reduced pressure
  6. customThe residue was purified by flash column chromatography over silica gel eluting with 30% ethyl acetate in hexane

Sources & evidence

ORD record
ord-de44db3b324e4d9ebb8001abb76926ab
Source dataset
uspto-grants-2008_08
Patent number
US07407980B2

Reaction notes

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