title: Absolute Configuration and Polymorphism of 2-Phenylbutyramide and α-Methyl-α-phenylsuccinimide.
abstract: 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 of1and2, obtained by chromatographic separation of racemates, were determined. It was revealed that racemate and homochiral forms of1are 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 of1allowed mimicking of crystal packing of the H-bonded ribbons in racemate1. Two polymorph modifications (monoclinic and orthorhombic) comprising very similar H-bondedzigzag-like chains were found for the homochiral forms of compound2that were significantly different in terms of crystal structure, IR spectra, and melting points from the racemic form of2. Unlike compound1, homochiral forms of compound2have 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.
authors.affiliation: Department of Biology & Chemistry, New Mexico Highlands University, 803 University Avenue, Las Vegas, New Mexico 87701, United States; A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, B-334, Moscow 119991, Russian Federation.
authors.forename: Victor N
authors.initials: VN
authors.lastname: Khrustalev
authors.affiliation: Department of Biology & Chemistry, New Mexico Highlands University , 803 University Avenue, Las Vegas, New Mexico 87701, United States.
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Sandhu
authors.affiliation: Department of Biology & Chemistry, New Mexico Highlands University , 803 University Avenue, Las Vegas, New Mexico 87701, United States.
authors.forename: Samuel
authors.initials: S
authors.lastname: Bentum
authors.affiliation: Department of Biology & Chemistry, New Mexico Highlands University , 803 University Avenue, Las Vegas, New Mexico 87701, United States.
authors.forename: Alexandr
authors.initials: A
authors.lastname: Fonari
authors.affiliation: Department of Biology & Chemistry, New Mexico Highlands University, 803 University Avenue, Las Vegas, New Mexico 87701, United States; Department of Basic & Social Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States.
authors.forename: Arcadius V
authors.initials: AV
authors.lastname: Krivoshein
authors.affiliation: Department of Biology & Chemistry, New Mexico Highlands University , 803 University Avenue, Las Vegas, New Mexico 87701, United States.
authors.forename: Tatiana V
authors.initials: TV
authors.lastname: Timofeeva