title: Determination of preferred conformations of ibuprofen in chloroform by 2D NOE spectroscopy.
abstract: Solution of an anti-inflammatory drug ibuprofen ((RS)-2-(4-isobutylphenyl) propionic acid) in chloroform was studied by nuclear magnetic resonance spectroscopy. A set of 2D NOESY spectra was analyzed in order to obtain atom-atom distances. Since ibuprofen is known to exist as an ensemble of different conformations, these distances are averaged over the ensemble. To compare experimental and calculated distances, three models of averaging were concerned. Our data allowed to determine the dominant conformers of ibuprofen dissolved in chloroform. The population of conformers in the saturated solution leads to a certain crystal morphology formed within the nucleation process. Observed and calculated (13)C chemical shifts (at the DFT/B3LYP/6-311+G(2d,p) level) were in good agreement.
authors.affiliation: Institute of Physics, Kazan Federal University, Kremlevskaya St. 18, Kazan 420008, Russia; G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya St. 1, Ivanovo 153045, Russia. Electronic address: Ilya.Khodov@gmail.com.
authors.forename: I A
authors.initials: IA
authors.lastname: Khodov
authors.affiliation: Institute of Physics, Kazan Federal University, Kremlevskaya St. 18, Kazan 420008, Russia.
authors.forename: S V
authors.initials: SV
authors.lastname: Efimov
authors.affiliation: Institute of Physics, Kazan Federal University, Kremlevskaya St. 18, Kazan 420008, Russia.
authors.forename: V V
authors.initials: VV
authors.lastname: Klochkov
authors.affiliation: G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya St. 1, Ivanovo 153045, Russia.
authors.forename: G A
authors.initials: GA
authors.lastname: Alper
authors.affiliation: Molecular Physical Chemistry R&D Unit, University of Coimbra, Coimbra 3004-535, Portugal.
authors.forename: L A E
authors.initials: LA
authors.lastname: Batista de Carvalho
mesh_terms: D002725:Chloroform / Q000737:chemistry*; D007052:Ibuprofen / Q000737:chemistry*; D008968:Molecular Conformation; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D012996:Solutions; D002725:Chloroform; D007052:Ibuprofen
keywords: 2D NOESY; Conformation; Ibuprofen (PubChem CID: 3672); NMR