Quinine → HCID 54462553, compound

Participants

Reaction Steps

154.65 g (0.65 mol) of racemic 6-cyclohexyl-2-isopropyl-4-hexenoic acid and 210.5 g (0.65 mol) of anhydrous quinine are dissolved in 1 liter of methanol. The mixture is concentrated by evaporation and the residue is recrystallised from ether/hexane. The crystallisate is filtered with suction and thoroughly washed with cold hexane. The salt is treated with 1N HCl and the acid is extracted with ether. Concentration by evaporation yields 6-cyclohexyl-2(R)-isopropyl-4-hexenoic acid of 90% ee. If the quinine salt is recrystallised a second time from ether/hexane before the treatment with HCl, the (R)-acid obtainable therefrom has a purity of more than 95% ee.

Provenance & Evidence