Quinine → (S)-2-(4-difluoromethoxyphenyl)-3-methylbutyric acid

Participants

Reaction Steps

Dissolve 50 g of 2-(4-difluoromethoxyphenyl)-3-methylbutyric acid in 130 g of toluene and to this solution is added 0.24 mole of resolving agent quinine. Heat the solution with stirring under reflux for 6 hours, then cool, filter, and transfer the resulting solids to 49 g of 15% hydrochloric acid. Heat the mixture with stirring at 40° C. for 2 hours and then allow the mixture to cool to room temperature. The resulting mixture is extracted with benzene 2-3 times, and the solvent benzene is then removed by distillation to give 21 g (yield: 42%) of (S)-2-(4-difluoromethoxyphenyl)-3-methylbutyric acid. [α]DRT =(+)40.5 (c=1.356 g/100 ml, CHCl2)

Provenance & Evidence