Methanol → Methyl 7-methoxy-1-benzofuran-2-carboxylate

HRID 2085166Notes

Reaction equation

HRID 2085166 reaction equation
S(Cl)(Cl)=O.[CH3:5][O:6][C:7]1[C:12]2[O:13][C:14]([C:16]([OH:18])=[O:17])=[CH:15][C:11]=2[CH:10]=[CH:9][CH:8]=1.[CH3:19]O>>[CH3:5][O:6][C:7]1[C:12]2[O:13][C:14]([C:16]([O:18][CH3:19])=[O:17])=[CH:15][C:11]=2[CH:10]=[CH:9][CH:8]=1

Participants

4

Reactant 3

HCID 887MethanolHCID 24386Thionyl ChlorideHCID 6060377-Methoxy-1-benzofuran-2-carboxylic acid

Product 1

HCID 12269509Methyl 7-methoxy-1-benzofuran-2-carboxylate

Procedure

Thionyl chloride (10 ml) was added dropwise to methanol (100 ml) with stirring under ice-cooling. 7-Methoxybenzo(b)furan-2-carboxylic acid (10 g) was successively added, and the mixture was refluxed under heating for 1 hr. After cooling, the solvent was evaporated under reduced pressure and the precipitated yellow crystals were collected by filtration to give methyl 7-methoxybenzo(b)furan-2-carboxylate (11.2 g). This was used in the next reaction without purification. Acetone oxime (4.8 g) was dissolved in tetrahydrofuran (100 ml), and butyllithium (1.6M hexane solution) (80 ml) was added dropwise to this solution at −5° C. with stirring. Thereafter, the mixture was stirred under ice-cooling for 1 hr, and a solution (50 ml) of methyl 7-methoxybenzo(b)furan-2-carboxylate (11.2 g) in tetrahydrofuran was added. The mixture was stirred at room temperature for 20 hr. A solution of sulfuric acid (28 g) dissolved in tetrahydrofuran (120 ml)—water (30 ml) was prepared, into which the reaction mixture was poured. The mixture was refluxed under heating for 2 hr. After cooling, the reaction mixture was poured into ice water and extracted with chloroform. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (2.1 g).

Workup

  1. temperaturecooling
  2. temperaturethe mixture was refluxed
  3. temperatureunder heating for 1 hr
  4. temperatureAfter cooling
  5. customthe solvent was evaporated under reduced pressure
  6. filtrationthe precipitated yellow crystals were collected by filtration

Sources & evidence

ORD record
ord-07ad952e4e844113a94a9aa32e38887e
Source dataset
uspto-grants-2004_04
Patent number
US06720320B2

Reaction notes

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