Computational <sup>1</sup>H and <sup>13</sup>C NMR of strychnobaillonine: On the way to larger molecules calculated at lower computational costs

Semenov, Valentin A.; Krivdin, Leonid B.

doi:10.1002/mrc.5088

Cited by 10 publications

(11 citation statements)

References 21 publications

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“…It is highly advisable to combine a database-oriented approach, as described here, with DFT calculations [ 59 , 60 ].…”

Section: Discussionmentioning

confidence: 99%

The Advantage of Automatic Peer-Reviewing of 13C-NMR Reference Data Using the CSEARCH-Protocol

Robien¹

2021

Molecules

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A systematic investigation of the experimental 13C-NMR spectra published in Molecules during the period of 1996 to 2015 with respect to their quality using CSEARCH-technology is described. It is shown that the systematic application of the CSEARCH-Robot-Referee during the peer-reviewing process prohibits at least the most trivial assignment errors and wrong structure proposals. In many cases, the correction of the assignments/chemical shift values is possible by manual inspection of the published tables; in certain cases, reprocessing of the original experimental data might help to clarify the situation, showing the urgent need for a public domain repository. A comparison of the significant key numbers derived for Molecules against those of other important journals in the field of natural product chemistry shows a quite similar level of quality for all publishers responsible for the six journals under investigation. From the results of this study, general rules for data handling, data storage, and manuscript preparation can be derived, helping to increase the quality of published NMR-data and making these data available as validated reference material.

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“…It is highly advisable to combine a database-oriented approach, as described here, with DFT calculations [ 59 , 60 ].…”

Section: Discussionmentioning

confidence: 99%

The Advantage of Automatic Peer-Reviewing of 13C-NMR Reference Data Using the CSEARCH-Protocol

Robien¹

2021

Molecules

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“…Further examples deal with the computation of 1 H and 13 C NMR chemical shifts of large natural productsstrychnobaillonine (77), [348] a dimeric indole alkaloid consisting of 46 non-hydrogen atoms plus 44 hydrogens and possessing 13 asymmetric centers and strychnohexamine (78), [349] an enormously large trimeric indole alkaloid possessing 66 second-row atoms and 60 hydrogens with 14 asymmetric centers. A number of essential reassignments and corrections to their 1 [314] with the permission of John Wiley and Sons…”

Section: Natural Productsmentioning

confidence: 99%

“…Indeed, a wide variety of natural products have been studied by means of computational 1 H NMR. Advances of computational NMR in structural and stereochemical applications of 1 H and 13 C NMR chemical shifts and spin–spin coupling constants of natural products are very well documented in hundreds of original publications by a number of principal authors including (listed alphabetically) Alvarenga, [ 307,308 ] Bifulco, [ 309–313 ] Buevich, et al, [ 311,314–319 ] Cen‐Pacheko, [ 320–324 ] Kutateladze, [ 325–332 ] Saielli and Bagno, [ 333–340 ] Sarotti, [ 30,33,341,342 ] Tantillo (see comprehensive reviews by this author [ 343,344 ] and references given therein), Semenov and Krivdin, [ 345–349 ] and many others. [ 350–353 ]…”

Section: Computational 1h and 13c Nmr In Stereochemical Studies Of In...mentioning

confidence: 99%

Computational¹H and¹³C NMR in structural and stereochemical studies

Krivdin

2022

Magnetic Reson in Chemistry

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Present review outlines the advances and perspectives of computational 1H and 13C NMR applied to the stereochemical studies of inorganic, organic, and bioorganic compounds, involving in particular natural products, carbohydrates, and carbonium ions. The first part of the review briefly outlines theoretical background of the modern computational methods applied to the calculation of chemical shifts and spin–spin coupling constants at the DFT and the non‐empirical levels. The second part of the review deals with the achievements of the computational 1H and 13C NMR in the stereochemical investigation of a variety of inorganic, organic, and bioorganic compounds, providing in an abridged form the material partly discussed by the author in a series of parent reviews. Major attention is focused herewith on the publications of the recent years, which were not reviewed elsewhere.

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“…This combination was recently recommended for larger organic molecules. [15][16][17][18][19][20] In all nuclear shielding calculations, the gauge including atomic orbitals (GIAO) [21][22][23][24][25] formalism was used.…”

Section: Calculationsmentioning

confidence: 99%

Azo‐hydrazone molecular switches: Synthesis and NMR conformational investigation

Kurutos

Kamounah

Dobrikov

et al. 2021

Magnetic Reson in Chemistry

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A series of five intramolecularly hydrogen-bonded arylhydrazone (aryl = phenol, p-nitrophenol, anisole, quinoline) derived molecular switches have been synthesized and characterized by NMR and HRMS techniques. It was found that the compounds exist as different isomers in solution. An investigation of both conformational and/or configurational changes of the azo-hydrazone compounds was carried out by 1D 1 H-and 13 C-spectra, 2D NOESY, COSY, HSQC, and HMBC techniques. It was found that these stimuli-responsive molecular switches exist mainly in the E form by intramolecularly hydrogen bonded between NH and the pyridine nitrogen at equilibrium. Deprotonation of the neutral E form yields the E 0 deprotonated isomer. Prediction of 13 C-NMR chemical shifts was achieved by DFT quantum mechanical calculations. Anions have traditionally been difficult to calculate correctly, so calculations of the anion using different functionals, basis sets, and solvent effects are also included. Deuterium isotope effects on the 13 C-NMR chemical shifts were employed in the assignments and furthermore utilized as indicators of intramolecular hydrogen bonding. Studies in various organic solvents including CDCl 3 , CD 3 CN, and DMSO-d 6 were also performed aiming to monitor dynamic changes over several days. The effect of the hydrogen bonded solvents leads to Z forms.

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Computational ¹H and ¹³C NMR of strychnobaillonine: On the way to larger molecules calculated at lower computational costs

Cited by 10 publications

References 21 publications

The Advantage of Automatic Peer-Reviewing of 13C-NMR Reference Data Using the CSEARCH-Protocol

The Advantage of Automatic Peer-Reviewing of 13C-NMR Reference Data Using the CSEARCH-Protocol

Computational¹H and¹³C NMR in structural and stereochemical studies

Azo‐hydrazone molecular switches: Synthesis and NMR conformational investigation

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Computational 1H and 13C NMR of strychnobaillonine: On the way to larger molecules calculated at lower computational costs

Cited by 10 publications

References 21 publications

The Advantage of Automatic Peer-Reviewing of 13C-NMR Reference Data Using the CSEARCH-Protocol

The Advantage of Automatic Peer-Reviewing of 13C-NMR Reference Data Using the CSEARCH-Protocol

Computational1H and13C NMR in structural and stereochemical studies

Azo‐hydrazone molecular switches: Synthesis and NMR conformational investigation

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Product

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Computational ¹H and ¹³C NMR of strychnobaillonine: On the way to larger molecules calculated at lower computational costs

Computational¹H and¹³C NMR in structural and stereochemical studies