Ethyl Acetate → Methyl 6-hydroxy-1-benzofuran-2-carboxylate

HRID 1055

Reaction equation

HRID 1055 reaction equation
B(Br)(Br)Br.C[O:6][C:7]1[CH:19]=[CH:18][C:10]2[CH:11]=[C:12]([C:14]([O:16][CH3:17])=[O:15])[O:13][C:9]=2[CH:8]=1.C(OCC)(=O)C>ClCCl>[OH:6][C:7]1[CH:19]=[CH:18][C:10]2[CH:11]=[C:12]([C:14]([O:16][CH3:17])=[O:15])[O:13][C:9]=2[CH:8]=1

Participants

5

Reactant 3

HCID 8857Ethyl AcetateHCID 25134Boron tribromideHCID 3016964Methyl 6-methoxybenzofuran-2-carboxylate

Product 1

HCID 12082972Methyl 6-hydroxy-1-benzofuran-2-carboxylateYield 73%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Boron tribromide (24.9 g) was added dropwise to a solution of methyl 6-methoxybenzofuran-2-carboxylate (18.6 g) in dichloromethane (200 ml) at 0° C., followed by stirring at room temperature for 1 day. The reaction mixture was poured over ice water; ethyl acetate (300 ml) was added. After the organic layer was washed with water and dried (MgSO4), the solvent was distilled off; 10% hydrochloric acid-methanol (60 ml) was added to the residue, followed by heating at 70° to 80° C. for 5 hours. The reaction mixture was concentrated under reduced pressure; the resulting crystals of methyl 6-hydroxybenzofuran-2-carboxylate (10.75 g) were collected by filtration using diethyl ether-isopropyl ether (2:1, v/v). The filtrate was concentrated; the residue was subjected to silica gel column chromatography. From the fraction eluted with diethyl ether-hexane (1:2, v/v), methyl 6-hydroxybenzofuran-2-carboxylate (1.75 g) was obtained (total yield 73%), which was then recrystallized from diethyl ether-isopropyl ether to yield colorless prisms having a melting point of 176° to 177° C.

Workup

  1. washAfter the organic layer was washed with water
  2. dry with materialdried (MgSO4)
  3. distillationthe solvent was distilled off
  4. addition10% hydrochloric acid-methanol (60 ml) was added to the residue
  5. temperatureby heating at 70° to 80° C. for 5 hours
  6. concentrationThe reaction mixture was concentrated under reduced pressure
  7. filtrationthe resulting crystals of methyl 6-hydroxybenzofuran-2-carboxylate (10.75 g) were collected by filtration
  8. concentrationThe filtrate was concentrated
  9. washFrom the fraction eluted with diethyl ether-hexane (1:2

Sources & evidence

ORD record
ord-c5d94e5973074b06af209206e6641b73
Source dataset
uspto-grants-1998_03
Patent number
US05723479

Linked notes

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