Separation of the Mixtures of Chiral Compounds by Crystallization

The effect of the eutectic composition on the outcome of kinetically and thermodynamically controlled resolutions that are based on the formation of diastereomers

“…Our initial assumption was confirmed by the experimental results, which showed good agreement between the average enantiomeric purity of the enantiomeric mixtures obtained from the corresponding diastereomers (ee DIA ) and the eutectic composition of the corresponding racemic compounds (ee EUrac ). 18,19 When resolutions were carried out with structurally unrelated resolving agents (45 examples), a similar correlation was observed between the average purity of the enantiomeric mixtures obtained after resolution (ee DIA : 78%) and the eutectic composition of the racemic compounds (ee EUrac : 73%). In those instances, when the eutectic composition of the resolving agent was higher than that of the racemic compound (29 examples), the parity was even higher between the average purity of enantiomeric mixtures (ee DIA : 80%) and the average eutectic composition of the resolving agents (ee EUres : 78%).…”

Regularities between Separations of Enantiomeric and Diastereoisomeric Mixtures. Prediction of the Efficiency of Diastereomeric/ Enantiomeric Separations on the Basis of Behaviour of Enantiomeric Mixtures

“…In this case, the racemic portion crystallized, while the enantiomeric excess of the free base (LEV soluble in water) may be precipitated from the mother liquor as the second fraction. [11] 2.2 The effect of the kinetic control during partial precipitation According to the binary melting point phase diagrams, the N-propionyl-phenylalanine (PPA) and the N-propionylphenylglycine (PPG) are racemates, but these compounds (PPA and PPG) behave like conglomerates [12] during partial precipitation (Fig. 2).…”

A Presumable Mechanism of the Separation of Diastereomeric and Enantiomeric Mixtures

“…The backbone of this macromolecule is an enantiomer, the phosphate of deoxyribose monomer. This chiral The solvent-dependency can also be observed at the resolution of racemic Amlodipine (AML) by (R,R)-tartaric acid (TA) (Scheme 10) but in this case the stoichiometry of diastereoisomers is determined by the eutectic composition of the resolving agent [11][12][13].…”