Occurrence of spontaneous resolution of ketoprofen with a racemic crystal structure by simple crystallization under nonequilibrium preferential enrichment conditions.

Nearly racemic ketoprofen, which satisfies the requirements for the occurrence of preferential enrichment, was spontaneously resolved into the two enantiomers by simple crystallization under nonequilibrium conditions using high concentrations

Case Study on the Interpretation of Crystal Structures Inducing Preferential Enrichment Based on the Graph Set Analysis of Hydrogen Bond Motifs

The hydrogen bond motifs in the racemic crystals of the first-generation of chiral organic compounds, which showed a good to excellent preferential enrichment (PE) phenomenon, were rationalized by graph set analysis in terms of the selective dissolution of the excess one enantiomer from the transformed disordered crystals. By comparing these motifs with those of several analogous compounds incapable of showing PE, the graph sets necessary to induce PE with respect to the first-generation compounds were unveiled. On the basis of this graph set study, compounds with a new type of crystal structure (β₁-form) and graph set which can induce PE have been revealed

A Novel Mechanism of Preferential Enrichment Phenomenon Observed for the Cocrystal of ( RS )‐2‐{4‐[(4‐Chlorophenoxy)methyl]phenoxy}propionic Acid and Isonicotinamide

International audienc

Order–Disorder Phase Transition between High- and Low- Z ′ Crystal Structures of the P 1 Space Group

International audienc

In Situ Observation of Polymorphic Transition during Crystallization of Organic Compounds Showing Preferential Enrichment By Means Of Temperature-Controlled Video-Microscopy and Time-Resolved X‑ray Powder Diffraction

A solvent-assisted solid-to-solid polymorphic transition, which was assumed to be one of the key processes for the occurrence of preferential enrichment (PE), has been proven to occur by means of temperature-controlled video-microscopy (TCVM) and time-resolved in situ X-ray powder diffraction (XRPD) measurement during crystallization of two typical first-generation chiral racemic compounds (<b>1</b> and <b>2</b>) showing an excellent PE phenomenon

Highly efficient chiral resolution of dl-arginine by cocrystal formation followed by recrystallization under preferential-enrichment conditions

An excellent chiral symmetry-breaking spontaneous enantiomeric resolution phenomenon, denoted preferential enrichment, was observed on recrystallization of the 1:1 cocrystal of dl-arginine and fumaric acid, which is classified as a racemic compound crystal with a high eutectic ee value (>95 %), under non-equilibrium crystallization conditions. On the basis of temperature-controlled video microscopy and in situ time-resolved solid-state 13C NMR spectroscopic studies on the crystallization process, a new mechanism of phase transition that can induce preferential enrichment is proposed