title: Zwitterionic phosphorylated quinines as chiral solvating agents for NMR spectroscopy.
abstract: Because of their unique 3D arrangement, naturally occurring Cinchona alkaloids and their synthetic derivatives have found wide-ranging applications in chiral recognition. Recently, we determined the enantioselective properties of C-9-phosphate mixed triesters of quinine as versatile chiral solvating agents in nuclear magnetic resonance (NMR) spectroscopy. In the current study, we introduce new zwitterionic members of this class of molecules containing a negatively charged phosphate moiety (i.e., ethyl, n-butyl and phenyl hydrogen quininyl phosphate). An efficient approach for synthesizing these compounds is elaborated, and full characterization, including conformational and autoaggregation phenomena studies, was performed. Therefore, their ability to induce NMR anisochrony of selected enantiomeric substrates (i.e., primarily N-DNB-protected amino acids and their methyl esters) was analyzed compared to uncharged diphenyl quininyl phosphate and its positively charged quaternary ammonium hydrochloride salt. In addition, (1) H and (13) C NMR experiments revealed their enantiodiscrimination potential toward novel analytes, such as secondary amines and nonprotected amino acids.
authors.affiliation: Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wrocław, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Rudzińska-Szostak
authors.affiliation: Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wrocław, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Górecki
authors.affiliation: Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wrocław, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Berlicki
authors.affiliation: Faculty of Chemistry, University of Wrocław, Wrocław, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Ślepokura
authors.affiliation: Department of Bioorganic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wrocław, Poland.
authors.forename: Artur
authors.initials: A
authors.lastname: Mucha
keywords: amino acids; enantiodiscrimination; nuclear magnetic resonance spectroscopy; phosphorylated quinine