A Combined Experimental and Computational Study of NHC-Catalyzed Allylation of Allenoate with MBH Esters: New Regiospecific and Seteroselective Access to 1,5-Enyne

2021 ◽  
Author(s):  
Fang Sun ◽  
Fangfang Lu ◽  
Xue Song ◽  
Wenchao Wu ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Dft Calculations ◽  
Computational Study ◽  
Quaternary Carbon ◽  
Aryl Aldehyde

An NHC-catalyzed regiospecific allylation of α-substituted allenoates with MBH carbonates derived from aryl aldehyde furnished highly functionalized 1,5-enynes bearing a quaternary carbon successfully. Combining with DFT calculations, the reaction mechanism...

scholarly journals Theoretical study on pegylation reaction mechanisms of IFN-α-2a, IFN-α-2b and IFN-β-1a

2017 ◽  
Vol 82 (7-8) ◽  
pp. 841-850
Author(s):  
Mohammad Taqavian ◽  
Daryoush Abedi ◽  
Fatemeh Zigheimat ◽  
Leila Zeidabadinejad
Keyword(s):  
Polyethylene Glycol ◽  
Reaction Mechanism ◽  
Dft Calculations ◽  
Transition State ◽  
Reaction Mechanisms ◽  
Theoretical Study ◽  
Computational Study ◽  
Single Transition ◽  
Experimental Works ◽  
Ab Initio And Dft

Ab initio and DFT calculations have been carried out to study the reaction mechanism between interferons (IFNs) ?-2a, ?-2b and ?-1a and polyethylene glycol (PEG) group. The calculations show that the mechanisms are concerted, in agreement with the results of experimental works. However, although it appears that there is one single transition state, the characteristics of its structure reveal a very synchronous reaction mechanism. The reactions are clearly exothermic and as well have feasible activation energies. Our computational study shows that the lowest transition state energies are related to Lys 134, His 34 and Met 1 of IFN-?-2a, IFN-?-2b and IFN-?-1a, respectively.

Succinylated isoniazid potential prodrug: Design of Experiments (DoE) for synthesis optimization and computational study of the reaction mechanism by DFT calculations

2021 ◽  
pp. 132323
Author(s):  
Diego Campos Prieto ◽  
Renan Vinícius de Araújo ◽  
Sara de Souza Lima ◽  
Felipe Zauith Assad ◽  
Scott M. Grayson ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Design Of Experiments ◽  
Dft Calculations ◽  
Computational Study

Computational study on gold-catalyzed (4 + 3) intramolecular cycloaddition of trienyne: mechanism, reactivity and selectivity

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73454-73468 ◽  
Author(s):  
Meng-Ru Li ◽  
Gui-Chang Wang
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Dft Calculations ◽  
Density Functional ◽  
Computational Study ◽  
Functional Theory ◽  
Intramolecular Cycloaddition

The reaction mechanism, reactivity and selectivity of the Au(i)-catalyzed intramolecular (4 + 3) cycloaddition of trienyne have been studied by density functional theory (DFT) calculations.

scholarly journals Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study

2020 ◽  
Vol 16 ◽  
pp. 1636-1648
Author(s):  
Csilla Hargitai ◽  
Györgyi Koványi-Lax ◽  
Tamás Nagy ◽  
Péter Ábrányi-Balogh ◽  
András Dancsó ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Dft Calculations ◽  
Single Crystal ◽  
Structure Elucidation ◽  
Computational Study ◽  
Nmr Studies ◽  
X Ray ◽  
Product Distributions ◽  
Acidic Conditions

Treatment of alkoxy-substituted o-(pivaloylaminomethyl)benzaldehydes under acidic conditions resulted in the formation of the regioisomeric aldehydes and/or dimer-like products. Detailed NMR studies and single-crystal X-ray measurements supported the structure elucidation of the compounds. DFT calculations were also carried out to clarify the reaction mechanism, and to explain the observed product distributions and structural variances in the dimer-like products. Studies on the transformation of unsubstituted o-(pivaloylaminomethyl)benzaldehyde under similar conditions were presented as well.

Reactions of an Aluminium(I) Reagent with 1,2-, 1,3- and 1,5-Dienes: Dearomatisation, Reversibility, and a Pericyclic Mechanism

2019 ◽  
Author(s):  
Clare Bakewell ◽  
Martí Garçon ◽  
Richard Y Kong ◽  
Louisa O'Hare ◽  
Andrew J. P. White ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Dft Calculations ◽  
Transition State ◽  
Reaction Pathways ◽  
Aromatic Rings ◽  
Aromatic Character ◽  
Pericyclic Reaction

The reactions of an aluminium(I) reagent with a series of 1,2-, 1,3- and 1,5-dienes are reported. In the case of 1,3-dienes the reaction occurs by a pericyclic reaction mechanism, specifically a cheletropic cycloaddition, to form aluminocyclopentene containing products. This mechanism has been interrogated by stereochemical experiments and DFT calculations. The stereochemical experiments show that the (4+1) cycloaddition follows a suprafacial topology, while calculations support a concerted albeit asynchronous pathway in which the transition state demonstrates aromatic character. Remarkably, the substrate scope of the (4+1) cycloaddition includes dienes that are either in part, or entirely, contained within aromatic rings. In these cases, reactions occur with dearomatisation of the substrate and can be reversible. In the case of 1,2- or 1,5-dienes complementary reactivity is observed; the orthogonal nature of the C=C π-bonds (1,2-diene) and the homoconjugated system (1,5-diene) both disfavour a (4+1) cycloaddition. Rather, reaction pathways are determined by an initial (2+1) cycloaddition to form an aluminocyclopropane intermediate which can in turn undergo insertion of a further C=C π-bond leading to complex organometallic products that incorporate fused hydrocarbon rings.

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 Catalytic mechanism of the colistin resistance protein MCR-1

2021 ◽  
Author(s):  
Reynier Suardíaz ◽  
Emily Lythell ◽  
Philip Hinchliffe ◽  
Marc van der Kamp ◽  
James Spencer ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Antimicrobial Resistance ◽  
Dft Calculations ◽  
Catalytic Reaction ◽  
Catalytic Mechanism ◽  
Cluster Models ◽  
Colistin Resistance ◽  
Resistance Protein ◽  
Catalytic Reaction Mechanism

Elucidation of the catalytic reaction mechanism of MCR-1 enzyme, responsible for the antimicrobial resistance to colistin, using DFT calculations on cluster models.

scholarly journals A computational study for the reaction mechanism of metal-free cyanomethylation of aryl alkynoates with acetonitrile

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18246-18251
Author(s):  
Selçuk Eşsiz
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Computational Study ◽  
Coupled Cluster ◽  
Functional Theory ◽  
Metal Free ◽  
Coupled Cluster Methods ◽  
High Level ◽  
Cluster Methods

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].

scholarly journals The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun
Keyword(s):  
Activation Energy ◽  
Dft Calculations ◽  
Energy Barrier ◽  
Computational Study ◽  
Strong Acid ◽  
Activation Energy Barrier ◽  
Pd Catalysts ◽  
Acid Ligand ◽  
Strong Acids

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.

A computational study on the mechanism of ynamide-mediated amide bond formation from carboxylic acids and amines

2017 ◽  
Vol 15 (30) ◽  
pp. 6367-6374 ◽  
Author(s):  
Song-Lin Zhang ◽  
Hai-Xing Wan ◽  
Zhu-Qin Deng
Keyword(s):  
Reaction Mechanism ◽  
Carboxylic Acids ◽  
Computational Study ◽  
Bond Formation ◽  
Amide Bond ◽  
Reactivity Pattern ◽  
Amide Bond Formation ◽  
Coupling Reagent ◽  
Catalytic Effects ◽  
Acid Substrate

A detailed computational study is presented on the reaction mechanism of ynamide-mediated condensation of carboxylic acids with amines to produce amides, which elucidates the reactivity pattern of the coupling reagent ynamide and discloses crucial bifunctional catalytic effects of the carboxylic acid substrate during aminolysis.

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