Über die Enantiomerentrennung durch Verteilung zwischen flüssigen Phasen. 4. Mitteilung. Enantioselektivität der diastereoisomeren Weinsäure-dimenthylester gegenüber α-Aminoalkohol-Salzen

Separation of Enantiomers by Partition between Liquid Phases. Enantioselectivity of Diastereoisomeric Dimenthyl Tartarates towards α-Aminoalcohol Salts The enantioselectivity of the easily obtainable diastereoisomeric dimenthyl tartarates I and II towards the salts of a series of α-aminoalcohols 1 - 10 was investigated by partition between aqueous and lipophilic phase. The measured enantiomer distribution constants Q (=K_A/K_B) confirm the previously observed configurational relationships between the lipophilic tartarates and the preferentially extracted enantiomer of the hydrophilic ammonium slat. However, the (R,R)-ester I is appreciably more selective than its (S,S)-diastereoisomer II or other previously investigated esters. The tartarates I - III transport norephedrin salts through bulk lipophilic membranes with enantioselectivity comparable to that observed in partition experiments. The most enantioselective ester I can be used as an efficient mobile phase for preparative separation of norephedrine enantiomers by flash partition chromatography.