Methyl 2-hydroxy-7-nitro-2,3-dihydrobenzofuran-4-carboxylate → Methyl 7-nitrobenzofuran-4-carboxylate

HRID 354053Notes

Reaction equation

HRID 354053 reaction equation
[CH3:1][O:2][C:3]([C:5]1[CH:6]=[CH:7][C:8]([N+:15]([O-:17])=[O:16])=[C:9]2[O:13][CH:12](O)[CH2:11][C:10]=12)=[O:4]>P(=O)(O)(O)O>[CH3:1][O:2][C:3]([C:5]1[CH:6]=[CH:7][C:8]([N+:15]([O-:17])=[O:16])=[C:9]2[O:13][CH:12]=[CH:11][C:10]=12)=[O:4]

Participants

3

Reactant 1

HCID 20738652Methyl 2-hydroxy-7-nitro-2,3-dihydrobenzofuran-4-carboxylate

Product 1

HCID 20738655Methyl 7-nitrobenzofuran-4-carboxylateYield 40%

Reagents, catalysts & solvents 1

HCID 1004Phosphoric AcidSolvent

Procedure

2-Hydroxy-7-nitro-2,3-dihydro-benzofuran-4-carboxylic acid methyl ester prepared above was heated in phosphoric acid (60 mL) at 100° C. for one hour. The reaction mixture was poured into ice water and the aqueous solution was extracted with ethyl acetate. The organic phase 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 15% ethyl acetate in hexane to give 7-nitro-benzofuran-4-carboxylic acid methyl ester as solid (2.3 g, 40%). 1H (CDCl3) δ: 4.04 (s, 3H), 7.54 (d, 1H, J=2.0 Hz), 7.95 (d, 1H, J=1.9 Hz), 8.07 (d, 1H, J=8.5 Hz), 8.17 (d, 1H, J=8.5 Hz).

Workup

  1. extractionthe aqueous solution was extracted with ethyl acetate
  2. washThe organic phase was washed with brine
  3. dry with materialdried (anhydrous sodium sulfate)
  4. concentrationconcentrated under reduced pressure
  5. customThe residue was purified by flash column chromatography over silica gel eluting with 15% ethyl acetate in hexane

Sources & evidence

ORD record
ord-88add26b2b5b4de4a5f62bbe1580379c
Source dataset
uspto-grants-2004_06
Patent number
US06756395B2

Reaction notes

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