Strategies in optical resolution: a practical guide

Separation of the Mixtures of Chiral Compounds by Crystallization

“…In the following example three kind of resolution of racemic ephedrine (EPh) via diastereoisomeric crystallization will be presented, as before. 40 The favourable resolving agent is a chiral diester of phosphoric acid containing 2-chloro-phenyl substituent (CPH), while the structurally similar phosphoric acid containing unsubstituted phenyl group (PH) is an unsuitable resolving agent.…”

“…2 Consequenlty, if the enantiomeric purity obtained after recrystallization or by other partial crystallization (as the result of splitting between the two phases) is plotted against the initial enantiomeric composition, either racemate or conglomerate behaviour is expected, or a conglomerate like curve is obtained (hereinafter: kineticconglomerate) ( Figure 2). 3 Fig. 1.…”

Gas antisolvent fractionation based optical resolution of ibuprofen with enantiopure phenylglycinol

“…Resolution of ibuprofen with (S)-phenylglycinol was previously investigated by the in situ method, without any success [42]. However, structural similarities [43] and differential scanning calorimetry (DSC) analysis results [44] suggest that (S)-phenylglycinol could be a suitable resolving agent. The efficiency of an optical resolution in general is strongly influenced by the properties of the solvent and the conditions under which the solid phase is formed.…”

Chiral β-Amino Alcohols as Ligands for the Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of N-Phosphinyl Ketimines

“…In addition, chiral amines have been extensively used as resolving agents [1][2][3][4], starting materials for the preparation of therapeutic drugs [5] and chiral auxiliaries in asymmetric synthesis [6][7][8]. Due to this, synthetic chemists have made great efforts in order to implement efficient procedures for the preparation of chiral amines [9,10] among which the reduction of iminic substrates plays a capital role.…”