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Study of stereoselective interactions of carbamoylated quinine and quinidine with 3,5‐dinitrobenzoyl α‐amino acids using VCD spectroscopy in the region of CH stretching vibrations
Author(s) -
Julínek Ondřej,
Lindner Wolfgang,
Urbanová Marie
Publication year - 2011
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20929
Subject(s) - chemistry , steric effects , chirality (physics) , circular dichroism , stereochemistry , stereoselectivity , enantiomer , quinidine , spectroscopy , vibrational circular dichroism , nuclear magnetic resonance spectroscopy , crystallography , organic chemistry , catalysis , chiral symmetry , medicine , physics , quantum mechanics , nambu–jona lasinio model , pharmacology , quark
The stereoselective complexation of tert ‐butylcarbamoyl quinine and tert ‐butylcarbamoyl quinidine selectors (SOs) with 3,5‐dinitrobenzoyl (DNB) derivatives of D ‐ and L ‐alpha amino acids (DNB‐Ala, DNB‐Val, DNB‐Leu, and DNB‐Ile) as well as achiral DNB‐Gly has been studied by vibrational circular dichroism (VCD) spectroscopy in the spectral region of CH stretching vibrations. All the complexes of SOs and sterically compatible enantiomers of derivatized amino acid selectands (SAs) showed induced circular dichroism (ICD) bands in the region of aromatic CH stretching vibrations, indicating the occurrence of a π–π interaction between the aromatic moieties of SA and SO. To our knowledge, this is the first report in which a π–π interaction was observed by VCD spectroscopy in this spectral region. No ICD bands were disclosed in the spectra of the sterically incompatible SA and SO complexes. The spectral pattern in the region of aliphatic CH stretching vibrations showed interaction‐induced conformational adaptations in sterically favorable SA and SO complexes. No such spectral changes were observed for any of the sterically incompatible complexes. The DNB‐Gly complexes exhibited spectral patterns similar to those observed for sterically favorable pairs of SOs and chiral SAs. Chirality, 2011. © 2010 Wiley‐Liss, Inc.