Dehydrocholic acid may be obtained in two polymorphic forms: a and b. The complete characterization and the crystal structure of the b-phase (obtained by unconventional powder diffraction methods) are described and discussed. Conversion of the a-form into the thermodynamically more stable b-polymorph may be obtained through a room temperature solvent-mediated process. On the other hand, transformation of the b-form into the a-form is realized through two distinct pathways: via a temperature-mediated process or as a guest-mediated solid state conversion, without the intervention of an amorphous state. R-(+)-Methyl p-tolyl sulfoxide is the guest of choice for this unusual b-to-a transformation.
Polymorphism of Dehydrocholic acid: Crystal Structure of the b-phase and Guest-Mediated Solid Phase Conversion.
FANTIN, Giancarlo;FOGAGNOLO, Marco;BORTOLINI, Olga;
2003
Abstract
Dehydrocholic acid may be obtained in two polymorphic forms: a and b. The complete characterization and the crystal structure of the b-phase (obtained by unconventional powder diffraction methods) are described and discussed. Conversion of the a-form into the thermodynamically more stable b-polymorph may be obtained through a room temperature solvent-mediated process. On the other hand, transformation of the b-form into the a-form is realized through two distinct pathways: via a temperature-mediated process or as a guest-mediated solid state conversion, without the intervention of an amorphous state. R-(+)-Methyl p-tolyl sulfoxide is the guest of choice for this unusual b-to-a transformation.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
