3-(2,2-Diethoxy-ethoxy)-5-methoxy-benzoic acid methyl ester → 4-Benzofurancarboxylic acid, 6-methoxy-, methyl ester

HRID 1643547Notes

Reaction equation

HRID 1643547 reaction equation
[CH3:1][O:2][C:3](=[O:21])[C:4]1[CH:9]=[C:8]([O:10][CH3:11])[CH:7]=[C:6]([O:12][CH2:13][CH:14](OCC)OCC)[CH:5]=1>C1C=CC=CC=1>[CH3:1][O:2][C:3]([C:4]1[CH:9]=[C:8]([O:10][CH3:11])[CH:7]=[C:6]2[O:12][CH:13]=[CH:14][C:5]=12)=[O:21]

Participants

3

Reactant 1

HCID 595603943-(2,2-Diethoxy-ethoxy)-5-methoxy-benzoic acid methyl ester

Product 1

HCID 595600184-Benzofurancarboxylic acid, 6-methoxy-, methyl esterYield 62.4%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

3-(2,2-Diethoxy-ethoxy)-5-methoxy-benzoic acid methyl ester (6b) (1.95 g, 6.53 mmol) was added to a solution of polyphosphoric acid (1.47 g) in benzene (10 mL). The reaction mixture was heated to reflux for 2 hr, filtered and concentrated. The residue was purified by flash column chromatography (5% EtOAc in hexanes) to give a pale yellow solid (840 mg, 62% yield). 1H NMR (400 MHz, CDCl3) δ 7.64 (d, J=2.27 Hz, 1 H) 7.61 (d, J=2.27 Hz, 1 H) 7.26 (d, J=2.02 Hz, 1 H) 7.25 (d, J=2.27 Hz, 1 H) 3.99 (s, 3 H) 3.90 (s, 3 H).

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureto reflux for 2 hr
  3. filtrationfiltered
  4. concentrationconcentrated
  5. customThe residue was purified by flash column chromatography (5% EtOAc in hexanes)

Sources & evidence

ORD record
ord-c881ad17010347a0ac92adceb8c0d88b
Source dataset
uspto-grants-2012_02
Patent number
US08119624B2

Reaction notes

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