Absolute Configuration and Polymorphism of 2-Phenylbutyramide and 伪-Methyl-伪-phenylsuccinimide

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• 作者：Victor N. Khrustalev ; Bhupinder Sandhu ; Samuel Bentum ; Alexandr Fonari ; Arcadius V. Krivoshein ; Tatiana V. Timofeeva
• 刊名：Crystal Growth & Design
• 出版年：2014
• 出版时间：July 2, 2014
• 年：2014
• 卷：14
• 期：7
• 页码：3360-3369
• 全文大小：634K
• ISSN：1528-7505

文摘

Crystal structures of racemic and homochiral forms of 2-phenylbutyramide (1) and 3-methyl-3-phenylpyrrolidine-2,5-dione (2) were investigated in detail by a single crystal X-ray diffraction study. Absolute configurations of the homochiral forms of 1 and 2, obtained by chromatographic separation of racemates, were determined. It was revealed that racemate and homochiral forms of 1 are very similar in terms of supramolecular organization (H-bonded ribbons) in crystal, infrared (IR) spectral characteristics, and melting points. The presence of two different molecular conformations in homochiral forms of 1 allowed mimicking of crystal packing of the H-bonded ribbons in racemate 1. Two polymorph modifications (monoclinic and orthorhombic) comprising very similar H-bonded zigzag-like chains were found for the homochiral forms of compound 2 that were significantly different in terms of crystal structure, IR spectra, and melting points from the racemic form of 2. Unlike compound 1, homochiral forms of compound 2 have a higher density than the corresponding racemate which contradicts the Wallach rule and indicates that, in this case, homochiral forms are more stable than racemate forms.