Theoretical conformational studies of podands containing (2S,4R)-4-hydroxyproline moieties

Borodina, Olga; Makarov, G. I.; Барташевич, Е. В.; Овчинникова, И. Г.; Titova, Yulia; Федорова, О. В.; Rusinov, Gennady L.; Charushin, Valery N.

doi:10.1007/s10593-019-02531-4

Cited by 4 publications

(5 citation statements)

References 22 publications

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“…As was demonstrated earlier by quantum-chemical calculations, the H a atom in the conformers 1a and 1c (Scheme and Figure ) with the highest correlation between calculated and experimental 1 H NMR spectra is oriented toward the O atom in an 2-alkoxyphenyl moiety and toward the N p atom in each branch heterocycle due to the intramolecular HB (Figure a). The formation of three-center intramolecular HB − leads to H a double deshielding from the side of close electronegative heteroatoms, and it is the reason for its downfield shift of 10.30 ppm in DMSO- d 6 in the experimental 1 H NMR spectrum (Table ).…”

Section: Resultssupporting

confidence: 72%

“…The range of signals for oxyethylene chain does not change when passing from the neutral form to bication. This is in agreement with comparisons performed in our previous work . For the pyrrolidine protons H p and H p ′, there is also a trend to higher values of CS in the bication than in podand 1c .…”

Section: Resultsmentioning

confidence: 99%

“…This is in agreement with comparisons performed in our previous work. 23 For the pyrrolidine protons H p and H p ′, there is also a trend to higher values of CS in the bication than in podand 1c.…”

mentioning

confidence: 90%

“…Our study is dedicated to the development of computer modeling and conformational analysis of C 2 -pseudosymmetric bridging podands 1 and 2 , known as acyclic analogs of crown ethers (Scheme ). Trifluoromethyl acetates of 4-hydroxypyrrolidine-2-carboxanilide podands are active chiral catalysts for the asymmetric Biginelli reaction .…”

Section: Introductionmentioning

confidence: 99%

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Pseudocyclic Form of 4-Hydroxypyrrolidine-2-carboxanilide Podands with Trioxyethylene Chain: Modeling, Conformational Search, and NMR Analysis

et al. 2021

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The 4-hydroxypyrrolidine-2-carboxanilide podand salt demonstrates catalytic activity in asymmetric Biginelli reaction. The systematic search for prevalent conformational state of the cation was carried out by computer simulations in combination with one-and two-dimensional NMR experiments. For that purpose, we proposed a novel algorithm for the generation and selection of conformers based on molecular dynamics and clustering in the space of principal components. The search had found an important trend of the podand to form a pseudocyclic structure with a horseshoe-shaped conformation of the oligooxyethylene fragment. This conformation is stabilized by different types of intramolecular hydrogen bonds between the acidic and basic centers of the two 4-hydroxypyrrolidine-2-carboxanilide residuals (branches). The proposed approach had made it possible to identify the major structural factors, providing a correlation between the calculated and experimental chemical shifts of hydrogen atoms in the 1 H NMR spectra of the protonated podand.

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Section: Resultssupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Pseudocyclic Form of 4-Hydroxypyrrolidine-2-carboxanilide Podands with Trioxyethylene Chain: Modeling, Conformational Search, and NMR Analysis

et al. 2021

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“…Среди хиральных катализаторов большой по-тенциал демонстрируют полифункциональные соединения на основе аминокислот [3], а также подандов, содержащих карбониламидные группы и аминокислотные остатки в своем составе [4]. Так, например, исследование внутримолекулярных водородных связей и конформационного поведения 4-гидроксипролин содержащих подандов с короткой цепью было реализовано с помощью комбинированного анализа расчетных и экспериментальных химических сдвигов [5]. Тонкие влияния нековалентных взаимодействий и водородных связей на энантиоселективность реакций может быть основой стратегии дизайна и отбора новых органокатализаторов [6].…”

Section: Introductionunclassified

Atomic Dipole Polarization in Predictions of Chemical Shifts of Amide and Pyrrolidine Protons

Borodina,

Bartashevich

2021

Chem

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A quantitative relationship has been established between the localization indices of electrons in atomic basins and chemical shifts of protons in amide and pyrrolidine fragments when they are present together in organic molecules. The fragments under consideration are important as key functional groups in the molecules of chiral inducers involved in stereoselective syntheses, in order to obtain drugs based on pyrimidinone heterocyclic systems. Integral properties of electron density, such as the magnitude of intra-atomic dipole polarization and charges of hydrogen atoms, calculated by integration of the electron density over the volumes of atomic basins, correlate with chemical shifts significantly better than the point atomic charges. Our proposed parametric model for the rapid prediction of chemical shifts is based on an equation that includes the electron localization index in the hydrogen atom basin as a factor. The developed approach offers a theoretical model for a rapid quantitative assessment of chemical shifts and makes it possible to formulate the main structural factors that provide correlation between the calculated and experimental chemical shifts of hydrogen atoms involved in intramolecular hydrogen bonds. It has been revealed that intramolecular hydrogen bonds are the main structural features that ensure the correlation of atomic integral characteristics with chemical shifts in the considered molecules. The results obtained in the course of theoretical modeling have been verified by comparison with the experimental 1H NMR data for 4-hydroxyproline-2-carboxanilide podands with different oxyethylene chain lengths, which are chiral inductors of stereoselective syntheses of drugs based on pyrimidinone heterocyclic systems.

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Evaluation of the effect of iminium intermediates on the stereoselectivity of the Biginelli reaction involving hydroxyproline-containing podands

Borodina,

Bartashevich,

Ovchinnikova

et al. 2023

Russ Chem Bull

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Theoretical conformational studies of podands containing (2S,4R)-4-hydroxyproline moieties

Cited by 4 publications

References 22 publications

Pseudocyclic Form of 4-Hydroxypyrrolidine-2-carboxanilide Podands with Trioxyethylene Chain: Modeling, Conformational Search, and NMR Analysis

Pseudocyclic Form of 4-Hydroxypyrrolidine-2-carboxanilide Podands with Trioxyethylene Chain: Modeling, Conformational Search, and NMR Analysis

Atomic Dipole Polarization in Predictions of Chemical Shifts of Amide and Pyrrolidine Protons

Evaluation of the effect of iminium intermediates on the stereoselectivity of the Biginelli reaction involving hydroxyproline-containing podands

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