Hydrochloric Acid → 6-(3-Chloro-5-fluoro-4-trifluoromethylphenyl)-3-propyltetrahydro-2-pyrone

Participants

Reaction Steps

A solution of 12.0 g (31.2 mmol) of ethyl=5-(3-chloro-5-fluoro-4-trifluoromethylphenyl)-5-hydroxy-2-propylpentanoate [prepared by reacting 3-propyl-5-formylpentanoic acid with 3-chloro-5-fluoro-4-trifluromethylphenylmagnesium bromide], 25 ml of a concentrated hydrochloric acid, and 100 ml of ethanol was heated at 50° C. while being stirred for 3 hours. To the reaction solution was added 50 ml of toluene, and the organic layer thus obtained was washed with a diluted aqueous sodium bicarbonate solution thrice and water thrice, and then dried over anhydrous magnesium sulfate. The solvent was distilled off under a reduced pressure and the residue was subjected to silica gel chromatography (eluent: heptane/toluene=1/1) to obtain 7.7 g of a crude 6-(3-chloro-5-fluoro-4-trifluoromethylphenyl)-3-propyltetrahydro-2-pyrone. (Yield: 73.3%)

Provenance & Evidence