Hydrochloric Acid → 6-Methoxy-5-(pentafluoroethyl)naphthalene-1-carboxylic acid

HRID 364444Notes

Reaction equation

[CH3:1][O:2][C:3]1[C:4]([C:17]([F:23])([F:22])[C:18]([F:21])([F:20])[F:19])=[C:5]2[C:10](=[CH:11][CH:12]=1)[C:9]([C:13]([O:15]C)=[O:14])=[CH:8][CH:7]=[CH:6]2.[OH-].[Na+].Cl>CO>[CH3:1][O:2][C:3]1[C:4]([C:17]([F:22])([F:23])[C:18]([F:19])([F:20])[F:21])=[C:5]2[C:10](=[CH:11][CH:12]=1)[C:9]([C:13]([OH:15])=[O:14])=[CH:8][CH:7]=[CH:6]2

Participants

Conditions

Temperature: 0 °C

Procedure

The 6-methoxy-5-(pentafluoroethyl)-1-naphthalenecarboxylic acid, methyl ester (2.82 g, 8.44 mmol), methanol (50 ml) and 2N aqueous sodium hydroxide (8.43 ml) were stirred at room temperature overnight. The mixture was cooled to 0° C., neutralized with 1N aqueous hydrochloric acid to pH 8 and the methanol evaporated off. Water was added to the residue and neutral impurities were removed by extraction with ethyl acetate. The aqueous layer was cooled to 0°, acidified to pH 1-3 with 1N aqueous hydrochloric acid, the product extracted with ethylacetate, the extract washed with brine and dried over anhydrous MgSO4. Evaporation gave 2.14 g of crude 6-methoxy-5-(pentafluoroethyl)-1-naphthalene carboxylic acid which was used, without further purification, in the next step. nmr (DMSO): δ4.05 (s, 3H, OCH3); δ8.0 (m, 4H, Har); δ9.1 (d, 1H, J=9, Har) ms: m/e 320 (M+), 303, 251, 203.

Workup

customthe methanol evaporated off
additionWater was added to the residue and neutral impurities
customwere removed by extraction with ethyl acetate
temperatureThe aqueous layer was cooled to 0°
extractionthe product extracted with ethylacetate
washthe extract washed with brine
dry with materialdried over anhydrous MgSO4
customEvaporation

Sources & evidence

ORD record: ord-b9589589f9454b4099f2a50b6d214532
Source dataset: uspto-grants-1986_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04604406

Reaction notes

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