Hydrochloric Acid → 7-Nitro-benzofuran-2-carboxylic acid

HRID 658178Notes

Reaction equation

O[C:2]1[CH:9]=[CH:8][C:7]([N+:10]([O-:12])=[O:11])=[CH:6][C:3]=1[CH:4]=O.[C:13](=[O:16])([O-])[O-:14].[K+].[K+].ClC[C:21](OC)=[O:22].[OH-].[K+].Cl>O.C1COCC1>[N+:10]([C:7]1[C:6]2[O:22][C:21]([C:13]([OH:14])=[O:16])=[CH:4][C:3]=2[CH:2]=[CH:9][CH:8]=1)([O-:12])=[O:11]

Participants

Conditions

Temperature: 130 °C

Procedure

3.0 g (17.9 mmol) of 2-hydroxy-5-nitrobenzaldehyde, 0.66 g (1.80 mmol) of tetra-N-butylammonium iodide and 9.92 g (71.81 mmol) of potassium carbonate are mixed, 4.09 g (37.7 mmol) of methyl chloroacetate are added and the mixture is heated at 130° C. for 4 h. 35 ml of THF and, with ice cooling, 6.04 g (107.71 mmol) of potassium hydroxide are added. Following the addition of 50 ml of water, the mixture is stirred at RT for 20 h. Using concentrated hydrochloric acid, the pH is adjusted to 0. The mixture is extracted with ethyl acetate. The organic phase is washed with water and dried over sodium sulfate. After the addition of silica gel, the mixture is concentrated and chromatographed on silica gel (mobile phase gradient: toluene to toluene/methanol/glacial acetic acid 35:5:1). Concentration of the product fractions and drying under reduced pressure gives 2.00 g (54% of theory) of the title compound.

Workup

extractionThe mixture is extracted with ethyl acetate
washThe organic phase is washed with water
dry with materialdried over sodium sulfate
additionAfter the addition of silica gel
concentrationthe mixture is concentrated
customchromatographed on silica gel (mobile phase gradient: toluene to toluene/methanol/glacial acetic acid 35:5:1)
customConcentration of the product fractions and drying under reduced pressure

Sources & evidence

ORD record: ord-6aa5e3806d4548188982f8c3686c775b
Source dataset: uspto-grants-2011_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08076355B2

Reaction notes

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