Crystal Structures, Dehydration Mechanism, and Chiral Discrimination in the Solid State of a Hydantoin Derivative

Stability of solid phases in the dexamathasone acetate/water system

“…Moreover, two anhydrous polymorphic forms (Form I and II) are known. The stability of DMA solid phases were investigated with the help of X-Ray powder diffraction under variable temperature and relative humidity [3], single crystal XRay diffraction, Dynamic Vapor Sorption [4][5][6] and TG-DSC.…”

Solubility of chiral species as function of the enantiomeric excess

“…Figure gives an example of a conglomerate which is hidden by the crystallization domain of the solvate <RS‐V n > of the racemic compound, whereas there is no stable nonsolvated racemic compound [25,26]. To enhance the solubility of the racemic composition, it is possible to change the solvent so that this solvate does not appear any more.…”

“…Figure 16 gives an example of a conglomerate which is hidden by the crystallization domain of the solvate <RS-Vn> of the racemic compound, whereas there is no stable nonsolvated racemic compound. [25,26] To enhance the solubility of the racemic composition, it is possible to change the solvent so that this solvate does not appear any more. Figure 17 shows that the solubility enhancement provided by high enantiomeric excess is cancelled because in that solvent at that temperature the enantiomers crystallize as solvates.…”

Supramolecular structure of 5-methyl-5-phenyl hydantoin and hydrogen-bonding patterns in 5,5′-substituted hydantoins

“…Some of the reported studies on hydantoins deal with the determination of their crystal structures [23][24][25][26] and the investigation of chirality effects in the solid state [27]. In fact, one chemical family of interest is that of 5-alkyl-5-arylhydantoins [28,29], since an unusual high propensity to crystallize as conglomerates has been reported among these derivatives.…”