Tag Archives: chirality

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 →

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 →

Poster presentation at 4th International DNP Symposium

2013-08-27NMR Events & Courses, Our Researchchirality, DNP, hyperpolarizationEva

logo_DNP_symposium

Find below an abstract of SeRMN contribution at 4th International DNP Symposium that will be held August 28-31, 2013, in Copenhagen (Denmak).

Enantiodiscrimination Studies by 13C DNP-NMR Spectroscopy

The determination of enantiomeric purity of drugs and/or endogenous molecules is crucial since its chirality could determine its pharmacological or biological behavior [1]. Many analytical techniques are available to determine the enantiomeric excess (ee) such as, circular dichroism, capillary electrophoresis, chromatographic techniques with chiral stationary phases, etc.; having each of them drawbacks and advantages [2]. Nuclear magnetic resonance (NMR) using a chiral solvating agent (CSA) as chiral auxiliary is an easy, fast and very powerful analytical tool that allows the measurement of ee by simple signal integration [3]. Continue reading Poster presentation at 4th International DNP Symposium →

Enantiodiscrimination Studies by ¹³C DNP-NMR Spectroscopy

2013-06-27Seminars13C-NMR, chirality, hyperpolarizationEva

SeRMN Seminar

Date: Thursday 27th June, 2013
Hour: 3 pm
Location: SeRMN, Facultats de Ciències i Biociències, C2/-135
Speaker: Eva Monteagudo, technician at SeRMN, UAB

Continue reading Enantiodiscrimination Studies by ¹³C DNP-NMR Spectroscopy →

Gelation process followed by NMR

2013-06-11Our Publicationschirality, foldamers, gelation, hydrogen-bonds, organogels, peptides, secondary structures, self-assemblyPau

Low-molecular-weight gelators consisting of hybrid cyclobutane-based peptides, by Sergi Celis, Pau Nolis, Ona Illa, Vicenç Branchadell, Rosa M. Ortuño, Organic & Biomolecular Chemistry 2013, 11, 2839 DOI: 10.1039/c3ob27347d

Some hybrid tetrapeptides consisting of (1R,2S)-2-aminocyclobutane-1-carboxylic acid and glycine, β-alanine, or γ-aminobutyric acid (GABA) joined in alternation, compounds 1–3, respectively, have been investigated to gain information on the non-covalent interactions responsible for their self-assembly to form ordered aggregates, as well as on parameters such as their morphology and size. All three peptides formed nice gels in many organic solvents and significant difference in their behaviour was not observed. Continue reading Gelation process followed by NMR →

Chiral secondary structure in β-peptides determined by NMR

2012-10-04Our Publicationschirality, conformational-study, foldamers, hydrogen-bonds, peptides, secondary structuresPau

“Secondary Structure of Short β-Peptides as the Chiral Expression of Monomeric Building Units: a Rational and Predictive Model”Esther Gorrea, Gabor Pohl, Pau Nolis, Sergio Celis, Kepa K Burusco, Vicenç Branchadell, András Perczel, and Rosa M. Ortuño. Journal Of Organic Chemistry. ACCEPTED 2012 DOI: 10.1021/jo302034b

Chirality of the monomeric residues controls and determines the prevalent folding of small oligopeptides (from di- to tetramers) composed of the 2-aminocyclobutane-1-carboxylic acid (ACBA) derivatives with the same or different absolute and relative configuration. The cis-form of the monomeric ACBA gives rise to two conformers, namely Z6 and Z8, while the trans-form manifests uniquely as an H8 structure. Continue reading Chiral secondary structure in β-peptides determined by NMR →

Doctoral thesis on new Chiral Solvating Agents based on molecular tweezers

2012-08-06News from the SeRMNchiralityEva

Last July I defended the doctoral thesis entitled “Nous agents de solvatació quiral tipus pinça amb anells antracènics: derivats de trifluorometilamines i trifluorometilcarbinols binòlics”.

The thesis focuses on the synthesis and behaviour of new Chiral Solvating Agents (CSA) based on molecular tweezers. The newly synthesized enantiopure compounds can be classified in two big groups:

the ones with a trifluoromethylanthrylamine backbone and an isopthalyc acid as a linking molecule, and
the trifluoromethylcarbinol derivatives linked by a BINOL molecule, which adds an additional stereogenic element due to its chiral axis.

Continue reading Doctoral thesis on new Chiral Solvating Agents based on molecular tweezers →

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 →

Structural study of γ,γ-peptides

2011-05-19Our Publicationschirality, conformational-study, hydrogen-bonds, nanometric size, peptides, secondary structures, self-assembly, vesiclesPau

“Synthesis and structural study of highly constrained hybrid cyclobutane-proline γ,γ-peptides” by R. Gutiérrez-Abad, D. Carbajo, P. Nolis, C. Acosta-Silva, J. A. Cobos, O. Illa, M. Royo and R. Ortuño. Aminoacids, Volume 41, pages 673-686, 2011. DOI: 10.1007/s00726-011-0912-4.

Two diastereomeric series of hybrid γ,γ-peptides derived from conveniently protected derivatives of (1R,2S)- and (1S,2R)-3-amino-2,2-dimethylcyclobutane-1-carboxylic acid and cis-4-amino-l-proline joined in alternation have efficiently been prepared through convergent synthesis. Continue reading Structural study of γ,γ-peptides →

Trans-cyclobutane β-dipeptides form organogels

2011-05-19Our Publicationschirality, conformational-study, hydrogen-bonds, molecular modeling, organogels, peptides, self-assemblyPau

“Self-Assembly of trans-Cyclobutane-Containing β-Dipeptides into Ordered Aggregates”,by E. Gorrea, P. Nolis, E. Torres, E. Da Silva, D. Amabilino, V. Branchadell and R. Ortuño; Chemistry – A European Journal, Volume 17, Issue 16, pages 4588–4597, April 11, 2011. DOI: 10.1002/chem.201002193

Two chiral synthetic β-dipeptides have been constructed, one with two trans-cyclobutane residues and the other with one trans and one cis fragment, 1 and 2, respectively, and investigated to get insight into the non-covalent interactions responsible for their self-assembly to form ordered aggregates, as well into parameters such as their morphology and size. Continue reading Trans-cyclobutane β-dipeptides form organogels →

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