Fries Rearrangement of Aryl Formates:  A Mechanistic Study by Means of1H,2H, and11B NMR Spectroscopy and DFT Calculations

2006 ◽  
Vol 71 (25) ◽  
pp. 9331-9340 ◽  
Author(s):  
Alessandro Bagno ◽  
Willi Kantlehner ◽  
Ralf Kress ◽  
Giacomo Saielli ◽  
Edmont Stoyanov
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Mechanistic Study ◽  
Fries Rearrangement

Fries Rearrangement of Aryl Formates Promoted by BCl3. Mechanistic Evidence from 11B NMR Spectra and DFT Calculations

2004 ◽  
Vol 59 (4) ◽  
pp. 386-397 ◽  
Author(s):  
Alessandro Bagno ◽  
Willi Kantlehner ◽  
Ralf Kreß ◽  
Giacomo Saielli
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Reaction Intermediates ◽  
Boron Compounds ◽  
Fries Rearrangement ◽  
Boron Trichloride ◽  
Nmr Chemical Shifts ◽  
11B Nmr

AbstractThe Fries rearrangement of model aryl formate esters, promoted by boron trichloride, has been investigated by means of NMR spectroscopy (both experimental and computational) and by DFT calculations. Firstly, the 11B NMR chemical shifts of a series of model boron compounds have been predicted by GIAO-B3LYP/6-31G(d,p) calculations, in order to make predictions of the chemical shifts of transient reaction intermediates observable by 11B NMR. Such 11B spectra for the reaction of two esters (phenyl and 3-methyoxyphenyl formates) have been obtained, and are found to follow different patterns which can be rationalized on the basis of computed chemical shifts. Secondly, DFT calculations (B3LYP/6-31G(d,p) level) have been employed to investigate several mechanistic pathways of the rearrangement of phenyl formate. It is found that the pathways leading to the lowest activation energies are those in which formyl chloride is generated from a complex between phenyl formate and BCl3, which then acts as the formylating agent.

DFT Study and Synthesis of Novel Bioactive Bispyrazole Using Mg/AlLDH as a Solid Base Catalyst

2020 ◽  
Vol 14 ◽  
Author(s):  
Soufiane Akhramez ◽  
Youness Achour ◽  
Mustapha Diba ◽  
Lahoucine Bahsis ◽  
Hajiba Ouchetto ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Finding ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Mechanistic Study ◽  
Knoevenagel Reaction ◽  
Solid Base ◽  
Reaction Conditions ◽  
Aryl Aldehyde

Background: In this study, an efficient synthesis of novel bispyrazole heterocyclic molecules by condensation of substituted aromatic aldehydes with 1,3-diketo-N-phenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst is reported. The attractive features of this protocol are as follows: mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Methods: The bispyrazole derivatives 3a-m were prepared by condensation reaction of substituted aromatic aldehydes with 1,3-diketo-Nphenylpyrazole by using Mg/Al-LDH as heterogeneous catalyst under THF solvent at the refluxing temperature. Objective: To synthesize a novel bispyrazole heterocyclic molecule may be have important biological activities and thus can be good candidates for pharmaceutical applications. Results: This protocol describes the Synthesis of Bioactive Compounds under mild reaction conditions, good yields and easiness of the catalyst separation from the reaction mixture. Further, a mechanistic study has been performed by using DFT calculations to explain the observed selectivity of the condensation reaction between aryl aldehyde and 1,3-diketo-N-phenylpyrazole via Knoevenagel reaction. The local electrophilicity/ nucleophilicity that allows explaining correctly the experimental finding. Conclusion: In summary, the pharmacologically interesting bis-pyrazole derivatives have been synthesized through Mg/Al-LDH as a solid base catalyst, in THF as solvent. Thus, the synthesized bioactive compounds containing the pyrazole ring may be have important biological activities and thus can be good candidates for pharmaceutical applications. Therefore, the catalyst Mg/Al-LDH showed high catalytic activity. Besides, a series of bispyrazole molecules were synthesized with a good yield and easy separation of the catalyst by simple filtration. Moreover, DFT calculations and reactivity indexes are used to explain the selectivity of the condensation reaction between aryl benzaldehyde and 1,3-diketo-Nphenylpyrazole via Knoevenagel reaction, and the results are in good agreement with the experimental finding.

scholarly journals Mechanistic Study on the Reaction of pinB-BMes2 with Alkynes Based on Experimental Investigation and DFT Calculations: Gradual Change of Mechanism Depending on the Substituent

2021 ◽  
Author(s):  
Linlin Wu ◽  
Chiemi Kojima ◽  
Ka Ho Lee ◽  
Shogo Morisako ◽  
Zhenyang Lin ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Transition Metal ◽  
Dft Calculations ◽  
Kinetic Analysis ◽  
Reaction Rate ◽  
Mechanistic Study ◽  
Isomer Ratio ◽  
Gradual Change ◽  
Isomeric Mixture ◽  
Metal Free

Transition-metal free direct and base-catalyzed 1,2-diborations of arylacetylenes using pinB-BMes2 provided syn/anti-isomeric mixture of diborylalkenes. The kinetic analysis showed that the reaction rate and isomer ratio were affected by reaction...

scholarly journals Synthesis, characterization and modeling of self-assembled porphyrin nanorods

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1346-1354 ◽  
Author(s):  
Danielle Laurencin ◽  
Pascal G. Yot ◽  
Christel Gervais ◽  
Yannick Guari ◽  
Sébastien Clément ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Powder Diffraction ◽  
Solid State Nmr ◽  
Molecular Level ◽  
Ion Association ◽  
Free Base ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

Porphyrin nanorods were prepared by ion-association between free-base meso 5,10,15,20-tetrakis-(4-[Formula: see text]-methylpyridinium)porphyrin cations and tetraphenylborate anions. The nanorods have variable lengths (up to a few micrometers long) and diameters ([Formula: see text]50–500 nm). Their structure at the molecular level was elucidated by combining multinuclear solid state NMR spectroscopy, synchrotron X-ray powder diffraction and DFT calculations.

scholarly journals Combining solid-state NMR spectroscopy with first-principles calculations – a guide to NMR crystallography

2016 ◽  
Vol 52 (45) ◽  
pp. 7186-7204 ◽  
Author(s):  
Sharon E. Ashbrook ◽  
David McKay
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
First Principles ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
First Principles Calculations ◽  
Recent Developments ◽  
Future Potential ◽  
Nmr Crystallography

DFT calculations are an important tool in assigning and interpreting NMR spectra of solids: we discuss recent developments and their future potential in the context of NMR crystallography.

Structure of 1-methyl-2-oxo-pyrido[2,1b][3,4]dihydropyrimidinium bromide studied by X-ray diffraction, FTIR and NMR spectroscopy and DFT calculations

2007 ◽  
Vol 843 (1-3) ◽  
pp. 107-115 ◽  
Author(s):  
M. Szafran ◽  
I. Kowalczyk ◽  
E. Bartoszak-Adamska ◽  
M. Jaskólski ◽  
B. Nowak-Wydra
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
X Ray Diffraction ◽  
X Ray

Structures of Nonheme Oxoiron(IV) Complexes from X-ray Crystallography, NMR Spectroscopy, and DFT Calculations

2005 ◽  
Vol 44 (24) ◽  
pp. 3690-3694 ◽  
Author(s):  
Eric J. Klinker ◽  
József Kaizer ◽  
William W. Brennessel ◽  
Nathaniel L. Woodrum ◽  
Christopher J. Cramer ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
X Ray ◽  
X Ray Crystallography

A computational mechanistic study of substrate-controlled competitive O–H and C–H insertion reactions catalyzed by dirhodium(ii) carbenoids: insight into the origin of chemoselectivity

2018 ◽  
Vol 5 (15) ◽  
pp. 2353-2363 ◽  
Author(s):  
Li-Han Zhu ◽  
Hai-Yan Yuan ◽  
Wen-Liang Li ◽  
Jing-Ping Zhang
Keyword(s):  
Dft Calculations ◽  
Mechanistic Study ◽  
Insertion Reactions ◽  
Rhodium Carbenoid ◽  
Insight Into

DFT calculations disclosed the chemoselectivity of rhodium carbenoid and water co-catalyzed O–H and C–H insertion reactions with three 1,3-diketone substrates.

Mechanistic study on the regioselective Ni-catalyzed dicarboxylation of 1,3-dienes with CO2

2020 ◽  
Vol 7 (24) ◽  
pp. 4080-4088
Author(s):  
Wan Nie ◽  
Yifan Shao ◽  
Mårten S. G. Ahlquist ◽  
Haizhu Yu ◽  
Yao Fu
Keyword(s):  
Dft Calculations ◽  
Mechanistic Study

DFT calculations revealed a new CO2 insertion mode different from conventional mechanisms in the Ni-catalyzed dicarboxylation of 1,3-dienes.

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