Methanol → Methyl 5-hydroxybenzofuran-2-carboxylate

Reaction equation

[OH:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([C:10]([OH:12])=[O:11])=[CH:7][C:6]=2[CH:13]=1.S(=O)(=O)(O)O.[CH3:19]O>>[CH3:19][O:11][C:10]([C:8]1[O:9][C:5]2[CH:4]=[CH:3][C:2]([OH:1])=[CH:13][C:6]=2[CH:7]=1)=[O:12]

Participants

Reactant 3

HCID 887Methanol

HCID 1118Sulfuric Acid

HCID 122089725-Hydroxybenzofuran-2-carboxylic acid

Product 1

HCID 12208973Methyl 5-hydroxybenzofuran-2-carboxylateYield 83%

Procedure

To a solution of 5-hydroxy-benzofuran-2-carboxylic acid (4.6 g, 26.0 mmol) in MeOH (100 mL) was added concentrated sulfuric acid (1.2 g, 13.0 mmol) and the resultant solution was heated (reflux, 18 h). The reaction was cooled (rt) and concentrated in vacuo. The resultant residue was purified by silica gel flash column chromatography using MeOH:DCM (10%) to provide the title compound (4.14 g, 83%). MS (ESI): mass calcd for C10H8O4, 192.0; m/z found, 193.1 [M+H]+. 1H NMR (500 MHz, CD3OD): 7.47 (s, 1H), 7.39 (d, J=9.0, 1H), 7.04 (d, J=2.5, 1H), 6.97 (dd, J=9.0, 2.5, 1H), 3.92 (s, 3H).