Hydrochloric Acid → (3R)-2-(4-chloro-2-methylphenyl)-4,4,4-trifluoro-3-methylbutanoic acid

Participants

Reaction Steps

3.10 g (crude, about 10.04 mmol) of ethyl (3R)-2-(4-chloro-2-methylphenyl)-4,4,4-trifluoro-3-methylbutanoate (diastereomer mixture) were dissolved in a mixture of 10 ml of methanol, 10 ml of THF and 5 ml of water, and 8.03 g of 50% strength aqueous sodium hydroxide solution were added at 0° C. The reaction mixture was stirred at RT overnight. The mixture was then acidified with 1 N hydrochloric acid (pH about 2) and extracted three times with ethyl acetate. The combined organic phases were washed with sat. sodium chloride solution, dried over magnesium sulphate and concentrated under reduced pressure. The residue was purified by chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 50:1 to 4:1). This gave 1.46 g (51.8% of theory) of the target product as a mixture of diastereomers (about 5:1).

Provenance & Evidence