Water → 2-Hydroxy-5-trifluoromethylbenzaldehyde

Hexamethylenetetramine (47.5 g) was added portionwise to a stirred solution of 4-trifluoromethylphenol (50 g) in trifluoroacetic acid (680 ml) and the mixture was heated at reflux temperature for 24 hours. After cooling, water (355 ml) was added followed by aqueous sulphuric acid (50% v/v, 190 ml) and the reaction was stirred at ambient temperature for 4 hours. The acidic aqueous phase was extracted with diethyl ether (3×500 ml). The combined organic extracts were washed with hydrochloric acid (5M, 3×500 ml) then water (500 ml) and dried over magnesium sulphate. The solvent was removed under reduced pressure and the residue purified by column chromatography on silica eluting with a 4:1 mixture of petroleum ether (b.p. 40-60° C.) and ethyl acetate. The appropriate fractions were combined and the solvent removed under reduced pressure to give 5-trifluoromethyl-2-hydroxybenzaldehyde (25 g) as a light pink solid.

1. temperaturethe mixture was heated
2. temperatureat reflux temperature for 24 hours
3. temperatureAfter cooling
4. extractionThe acidic aqueous phase was extracted with diethyl ether (3×500 ml)
5. washThe combined organic extracts were washed with hydrochloric acid (5M, 3×500 ml)
6. dry with materialwater (500 ml) and dried over magnesium sulphate
7. customThe solvent was removed under reduced pressure
8. customthe residue purified by column chromatography on silica eluting with a 4:1 mixture of petroleum ether (b.p. 40-60° C.) and ethyl acetate
9. customthe solvent removed under reduced pressure

ORD record

ord-0ce053cad8ab4ff09960d1c85304ecd6

Source dataset

uspto-grants-2000_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06136825