Resolution of DL-racemic mixtures
AssigneesDegussa AG, Yeda Research and Development Co. Ltd.
InventorsMatthias Kottenhahn, Guenter Knaup, Karlheinz Drauz, Meir Lahav, David Zbaida
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Abstract
The present invention relates to a process for the resolution of DL-racemic mixtures of compounds which crystalize in the form of a conglumerate. Both, the D and L-enantiomers are obtained according to the invention in a industrially feasable process by adding chiral enantioselective polymers to the supersaturated solution of the racemat to inhibit crystalization of one enantiomer. Next a DL-racemic mixture of said compound is suspended in about twice the amount of the crystallized enantiomer. Consequently, the opposite enantiomer could be recovered by said suspension by physical separation.
Claims12
A process for the resolution of a DL-racemic mixture of a compound crystallizing in the form of a conglomerate from a supersaturated solution thereof, to recover both the D and the L enantiomers, which process comprises the steps of:
- a) effecting a preferential crystallization of one of said enantiomers from said supersaturated solution in the presence of an effective amount of a chiral enantioselective polymer which inhibits the crystallization of the opposite enantiomer;
- b) physically separating the thus crystallized said one enantiomer to obtain a mother liquor comprising an excess of said opposite enantiomer;
- c) adding to said mother liquor solid DL-racemic mixture of said compound in about twice the amount of said one enantiomer separated in step (b) and stirring the resulting suspension at a suitable temperature until substantially the entire suspended solid phase consists of said opposite enantiomer;
- and
- d) physically separating said solid opposite enantiomer, to obtain a solution having substantially the same composition as the initial solution used in step (a).
Dependencies are inferred from the claim text.