Phase Transformations of a Conformational Solvatomorphic Steroid: [23(23E,25R]-23(28)-(3′-Acetoxybenzyliden)-5α-spirostan-3β-ol acetate

• Published in: Crystal growth & design Vol. 20; no. 10; pp. 6649 - 6659
• Main Authors: Ramos-Enrı́quez, Manuel A, Colin-Molina, Abraham, Flores-Álamo, Marcos, Rodríguez-Molina, Braulio, Iglesias-Arteaga, Martín A
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.10.2020
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.0c00808

[23­(23E,25R]-23­(28)-(3′-Acetoxybenzyliden)-5α-spirostan-3β-ol acetate herein described showed a high tendency to crystallize, growing two solvent-free forms and six solvates that were solved by X-ray diffraction experiments. Molecules in each crystal showed important differences in their crystal packing and molecular conformations, especially in the positions adopted by the benzylidene moiety. Calorimetric and powder X-ray diffraction experiments revealed that, after desolvation, all but one of the solvates undergo a phase transition toward a crystalline solvent-free form. The analysis of these arrays, phase transitions, and the accompanying conformational changes can help to understand the interplay among the solvent, the framework flexibility, and the intermolecular interactions in the solid-state structure of biologically active molecules.