Cinchona alkaloids as privileged chiral solvating agents for the enantiodiscrimination of N-protected aminoalkanephosphonates—a comparative NMR study

Rudzińska, Ewa; Berlicki, Łukasz; Kafarski, Paweł; Lämmerhofer, Michael; Mucha, Artur

doi:10.1016/j.tetasy.2009.11.003

Cited by 22 publications

(16 citation statements)

References 33 publications

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“…DNB derivatives were introduced because the presence of an electron-poor aromatic ring enhances the interaction with the electron-rich quinoline fragment of the receptor. In general, the application of zwitterionic phosphorylated quinines (2a-c; ligand : CSA concentration 10 mM : 10 mM) resulted in discrimination of the enantiomers of eleven (3)(4)(5)(6)(7)(8)(9)(10)(11)15, and 16) of the 14 studied compounds (Table 2; Table S1 in the Supporting Information). In general, the application of zwitterionic phosphorylated quinines (2a-c; ligand : CSA concentration 10 mM : 10 mM) resulted in discrimination of the enantiomers of eleven (3)(4)(5)(6)(7)(8)(9)(10)(11)15, and 16) of the 14 studied compounds (Table 2; Table S1 in the Supporting Information).…”

Section: H Nmr Enantiodiscrimination Potency Of Phosphorylated Quininesmentioning

confidence: 99%

“…Quinine has been extensively studied as a chiral solvating agent for 1 H, 19 F, 31 P, and 119 Sn nuclear magnetic resonance (NMR) spectroscopy, and it is able to induce anisochrony of the enantiotopic nuclei of various substrates. [8][9][10] The multifunctional nature of quinine enables modulation of its enantiodiscrimination potential by selective modifications. [8][9][10] The multifunctional nature of quinine enables modulation of its enantiodiscrimination potential by selective modifications.…”

mentioning

confidence: 99%

“…Therefore, this natural alkaloid was successfully used for the enantiodiscrimination of acids , alcohols and hydroxyesters, 1-4 hemiacetals and acetals, 5 binaphthyl compounds and alkylarylcarbinols, 6,7 and amino-and hydroxyphosphonates. [10][11][12][13][14][15][16][17] In particular, C9-carbamoylated quinines revealed complementary enantiodiscriminating properties with respect to native quinine toward a range of chiral substrates, such as amines, acids, amides, and N-protected amino acids. For the application of quinine analogs as chiral solvating agents (CSA) for NMR spectroscopy, much attention has been focused on carbamoyl derivatives modified at the C9, C22, and C23 positions.…”

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confidence: 99%

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Zwitterionic Phosphorylated Quinines as Chiral Solvating Agents for NMR Spectroscopy

et al. 2015

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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.

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Section: H Nmr Enantiodiscrimination Potency Of Phosphorylated Quininesmentioning

confidence: 99%

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Zwitterionic Phosphorylated Quinines as Chiral Solvating Agents for NMR Spectroscopy

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“…Thus, 1 H NMR has served to determine the optical purity of secondary alcohols obtained through the enantioselective addition of diethylzinc to furaldehydes,16 as well as for the analysis of β‐hydroxy esters17 and cyclic hemiacetals and methyl acetals 18. Secondary and tertiary α‐aryl‐α‐trifluoromethyl alcohols and hydroxyesters were studied by the use 19 F NMR,19 whereas 31 P NMR allowed enantiodiscrimination of 1‐hydroxy,20 1,2‐dihydroxyalkanephosphonates21 and N ‐benzyloxycarbonylamino‐phosphonates22 in our group. Triphenyltin‐modified alcohols and acids showed chemical shift anisochrony in 119 Sn NMR 23.…”

Section: Introductionmentioning

confidence: 99%

Phosphorylation as a method of tuning the enantiodiscrimination potency of quinine—An NMR study

et al. 2012

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Quinines phosphorylated at the C-9 hydroxyl group (diphenyl and diethyl phosphates) were synthesized and validated as novel effective chiral solvating agents in two alternative methods based on (1)H and (31)P NMR spectroscopy. Tested with a representative set of racemic analytes, the title compounds induced shift nonequivalence effects in (1)H NMR signals with values up to 0.1-0.2 ppm for 3,5-dinitrobenzoyl-substituted amino acids. In terms of enantiodifferentiation extent and application range, introduction of a phosphate group was proven to be superior compared to the action of nonmodified quinine. Interestingly, a temperature decrease to reach the slow exchange conditions also produced nonequivalences in the (31)P NMR spectra of the selectors. Comprehensive NMR analysis showed the existence of two conformations (closed 1 and 2) for both quinines in their free forms and the open 3 arrangement for the protonated ones. The crystal structure of diethylphosphorylquinine hydrochloride dichloromethane hemisolvate revealed a similar conformation to that observed in solution. Structures of complexes of phosphorylated quinines with selected ligands were determined with the use of NMR-based molecular modeling studies.

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“…As a consequence, they exist in solution in cis - and trans- forms, with the equilibrium strongly shifted towards the formation of trans -isomers [22]. …”

Section: Resultsmentioning

confidence: 99%

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates

Górniak¹,

Czernicka²,

Młynarz³

et al. 2014

Beilstein J. Org. Chem.

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Cinchona alkaloids as privileged chiral solvating agents for the enantiodiscrimination of N-protected aminoalkanephosphonates—a comparative NMR study

Cited by 22 publications

References 33 publications

Zwitterionic Phosphorylated Quinines as Chiral Solvating Agents for NMR Spectroscopy

Zwitterionic Phosphorylated Quinines as Chiral Solvating Agents for NMR Spectroscopy

Phosphorylation as a method of tuning the enantiodiscrimination potency of quinine—An NMR study

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates

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