Tag Archives: enantiodifferentiation

Review – Pure shift NMR experiments: recent developments, methods and applications

2015-05-02Methods & Applications, NMR Bibliography, Our Publications, Our Researchenantiodifferentiation, enhanced resolution, full sensitivity, heteronulear coupling constants, HOBS, HOBS-HSQC, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, Pure shift, Relaxation times, resolution enhancement, review, SAPS-HSQC, sensitivity enhancement, T1-relaxation, T2-relaxationLaura

“Broadband ¹H homodecoupled NMR experiments: recent developments, methods and applications” by Laura Castañar and Teodor Parella. Magnetic Resonance in Chemistry, 2015. DOI: 10.1002/mrc.4238

In recent years, a great interest in the development of new broadband ¹H homonuclear decoupled techniques providing simplified J_HH multiplet patterns has emerged again in the field of small molecule NMR. The resulting highly resolved ¹H NMR spectra display resonances as collapsed singlets, therefore minimizing signal overlap and expediting spectral analysis. This review aims at presenting the most recent advances in pure shift NMR spectroscopy, with a particular emphasis to the Zangger–Sterk experiment. Continue reading Review – Pure shift NMR experiments: recent developments, methods and applications →

NMR-Aided Differentiation of Enantiomers: Signal Enantioresolution

2015-03-24Methods & Applications, Our Publications, Our Researchchirality, enantiodifferentiationMiriam

“NMR-Aided Differentiation of Enantiomers: Signal Enantioresolution” by Míriam Pérez-Trujillo, Teodor Parella and Lars T. Kuhn. Analytica Chimica Acta, 2015. DOI: 10.1016/j.aca.2015.02.069

NMR-aided enantiodiscrimination using chiral auxiliaries (CAs) is a recognized method for differentiating enantiomers and for measuring enantiomeric ratios (er). Up to the present, the study, optimization, and comparison of such methods have been performed based on the enantiodifferentiation of NMR signals via analysing non-equivalent chemical-shift values (ΔΔδ) of the diastereoisomeric species formed. However, a poor and non-reliable comparison of results is often obtained via the analysis of ΔΔδ exclusively. In here, the concept of enantioresolution of an individual NMR signal and its importance for NMR-aided enantiodifferentiation studies is introduced and discussed. Continue reading NMR-Aided Differentiation of Enantiomers: Signal Enantioresolution →

SeRMN presentations at the 2014 Ibero-American NMR & GERMN Bienal & Iberian NMR meeting

2014-09-15Methods & Applications, NMR Events & Courses, Our Researchchirality, enantiodifferentiation, enhanced resolution, full sensitivity, HOBS, HOBS-TOCSY, homodecoupling, homonuclear decoupling, multipl, pure-shift NMRLaura

Some of our last research work will be presented next week at the VI Ibero-American NMR – VII GERMN Bienal – IV Iberian NMR joint meeting that will take place in Alcalá de Henares, Madrid (Spain) from 22^nd to 25^th September. Find below a summary of our contributions.

Laura Castañar presents an oral communication and a poster entitled “Enantiodifferentiation throgh frequency-selective pure shift ¹H NMR”. NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method to carry out enantiodifferentiation studies. Continue reading SeRMN presentations at the 2014 Ibero-American NMR & GERMN Bienal & Iberian NMR meeting →

Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra

2014-07-17Methods & Applications, Our Publications, Our Researchchirality, enantiodifferentiation, enhanced resolution, homodecoupling, homonuclear decoupling, HSQC, pure-shift NMR, spectral aliasingMiriam

“Simultaneous ¹H and ¹³C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra” by Miriam Pérez-Trujillo, Laura Castañar, Eva Monteagudo, Lars T. Kuhn, Pau Nolis, Albert Virgili, R. Thomas Williamson and Teodor Parella. Chemical Communications 50:10214-10217 (2014). DOI: 10.1039/C4CC04077E

NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method of enantiodifferentiation and measurement of enantiomeric ratios (er). The analysis is traditionally performed by observing chemical shift differences (ΔΔδ) in ¹H signals by conventional 1D ¹H NMR spectra. However, low ΔΔδ values and signal overlap caused by complex multiplets lead to the lack of spectral signal dispersion that preclude a straightforward analysis. Continue reading Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra →

Presentations at the EUROMAR 2014 Conference

2014-06-18News from the SeRMN, NMR Events & Courses, Our Researchenantiodifferentiation, EUROMAR, heteronulear coupling constants, HOBS, homonuclear decoupling, NMR Conference, pure-shift NMRLaura

EUROMAR 2014

In a few days several SeRMN members will present our research work at the annual meeting of the European magnetic resonance community EUROMAR 2014 Conference that will take place in Zurich (Switzerland) from 29^thJune to 3^th July. Find below a summary of our contributions. Continue reading Presentations at the EUROMAR 2014 Conference →

HOBS Applications

2014-03-26Methods & Applications, Our Research, Seminarsenantiodifferentiation, enhanced resolution, full sensitivity, HOBS, HOBS-HSQC, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, proton-carbon coupling constants, pure-shift NMRLaura

SeRMN seminar

Date: Friday 28th March, 2014
Hour: 12 am
Location: SeRMN, Facultats de Ciències i Biociències, C2/-135
Speaker: Laura Castañar, SeRMN PhD Student & Teaching Assistant, Dept. of Chemistry.

Several NMR applications using HOmodecouped Band-Selective NMR experiments [1] are proposed. The easy implementation of this HOBS scheme as a general building block into a great variety of multidimensional NMR experiments leads to pure-shift spectra with enhanced resolution and with the maximum attainable sensitivity. In this talk is presented the application of HOBS for measuring direct [1] and long-range [2] heteronuclear coupling constants. Also the use of HOBS experiments to enantiodiscrimination studies are presented [3].

Reference:

[1] “Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments” by L. Castañar, P. Nolis, A. Virgili and T. Parella. Chem. Eur. J. 2013, 19, 17283-17286. DOI: 10.1002/chem.201303235

[2] “Implementing homo- and heterodecoupling in region-selective HSQMBC experiments” by Laura Castañar, Josep Sauri, Pau Nolis,Albert Virgili and Teodor Parella. Journal of Magnetic Resonance,2014, 238, 63-69. DOI:10.1016/j.jmr.2013.10.022

[3] “Enantiodifferentiation through Frequency-Selective Pure-Shift 1H Nuclear Magnetic Resonance Spectroscopy” by Laura Castañar, Míriam Pérez-Trujillo, Pau Nolis, Eva Monteagudo , Albert Virgili and Teodor Parella. ChemPhysChem, 2014. DOI: 10.1002/cphc.201301130

Continue reading HOBS Applications →

Rapid and efficient enantiodifferentiation through frequency-selective pure-shift ¹H NMR spectroscopy

2014-03-06Methods & Applications, Our Publications, Our Researchband-selective, enantiodifferentiation, enhanced resolution, full sensitivity, HOBS, homodecoupling, homonuclear decoupling, pure-shift NMRLaura

“Enantiodifferentiation through Frequency-Selective Pure-Shift ¹H Nuclear Magnetic Resonance Spectroscopy” by Laura Castañar, Míriam Pérez-Trujillo, Pau Nolis, Eva Monteagudo , Albert Virgili and Teodor Parella. ChemPhysChem,15 (2014) 854-857.

DOI: 10.1002/cphc.201301130

A frequency-selective 1D ¹H NMR experiment for the fast and sensitive determination of chemical shift differences between overlapped resonances is proposed. The resulting fully homodecoupled ¹H resonances appear as resolved 1D singlets without their typical J_HH multiplet structure. The achieved high signal dispersion is here exploited in enantiodiscrimination studies using chiral solvating agents. Continue reading Rapid and efficient enantiodifferentiation through frequency-selective pure-shift ¹H NMR spectroscopy →

Enantiodifferentiation through 13C NMR Spectroscopy and CSAs

2013-11-19Methods & Applications, Our Publications, Our Research13C-NMR, chirality, enantiodifferentiation, metabolomicsMiriam

“¹³C NMR spectroscopy for the differentiation of enantiomers using chiral solvating agents” Míriam Pérez-Trujillo, Eva Monteagudo and Teodor Parella. Analytical Chemistry, 2013, 85 (22), pp 10887–10894. DOI: 10.1021/ac402580j

The utility of ¹³C NMR spectroscopy for the differentiation of enantiomers using chiral solvating agents (CSA) is stated. Three examples involving the enantiodifferentiation of a drug, a metabolite and a reactant in aqueous and organic solutions have been chosen to show it. Continue reading Enantiodifferentiation through 13C NMR Spectroscopy and CSAs →

CHIRAL METABONOMICS: Giving Metabonomics a Chiral Dimension

2012-02-20Methods & Applications, Our Publications, Our Researchchirality, enantiodifferentiation, medical research, metabolomics, pharmaceuticalMiriam

“Chiral Metabonomics: 1H NMR-Based Enantiospecific Differentiation of Metabolites in Human Urine via Direct Cosolvation with β-Cyclodextrin” Míriam Pérez-Trujillo, John C. Lindon, Teodor Parella, Hector C. Keun, Jeremy K. Nicholson and Toby J. Athersuch. Analytical Chemistry, February 2012 DOI:10.1021/ac203291d

Differences in molecular chirality remain an important issue in drug metabolism and pharmacokinetics for the pharmaceutical industry and regulatory authorities and chirality is an important feature of many endogenous metabolites. We present a 1H NMR-based method for the rapid, direct differentiation and identification of chiral drug enantiomers in human urine without pre-treatment of any kind. Continue reading CHIRAL METABONOMICS: Giving Metabonomics a Chiral Dimension →

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