Probing the structural and electronic effects to stabilize nonplanar forms of thioamide derivatives: A computational study

2011 ◽  
Vol 32 (10) ◽  
pp. 2170-2176 ◽  
Author(s):  
Manoj K. Kesharwani ◽  
Bishwajit Ganguly
Keyword(s):  
Computational Study ◽  
Electronic Effects

A family of mixed-ligand oxidovanadium(v) complexes with aroylhydrazone ligands: a combined experimental and computational study on the electronic effects of para substituents of hydrazone ligands on the electronic properties, DNA binding and nuclease activities

RSC Advances ◽  
2015 ◽  
Vol 5 (112) ◽  
pp. 92456-92472 ◽  
Author(s):  
Debashis Patra ◽  
Nirmalendu Biswas ◽  
Bhavini Kumari ◽  
Prolay Das ◽  
Nayim Sepay ◽  
...  
Keyword(s):  
Dna Binding ◽  
Electronic Properties ◽  
Computational Study ◽  
Nuclease Activity ◽  
Mixed Ligand ◽  
Electronic Effects ◽  
Binding Ability ◽  
Marked Influence ◽  
Hydrazone Ligands

Substituents at 5-position in the acetophenone ring of the hydrazone ligands in a family of mixed-ligand oxidovanadium(v) complexes show marked influence on the electronic properties, DNA binding ability and nuclease activity.

scholarly journals Computational Study of Ortho-Substituent Effects on Antioxidant Activities of Phenolic Dendritic Antioxidants

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 189 ◽  
Author(s):  
Choon Young Lee ◽  
Ajit Sharma ◽  
Julius Semenya ◽  
Charles Anamoah ◽  
Kelli N. Chapman ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Electron Transfer ◽  
Antioxidant Activities ◽  
Computational Study ◽  
Radical Scavenging ◽  
Substituent Effects ◽  
Phenolic Antioxidants ◽  
Electronic Effects ◽  
Total Enthalpy ◽  
Structure Activity

Antioxidants are an important component of our ability to combat free radicals, an excess of which leads to oxidative stress that is related to aging and numerous human diseases. Oxidative damage also shortens the shelf-life of foods and other commodities. Understanding the structure–activity relationship of antioxidants and their mechanisms of action is important for designing more potent antioxidants for potential use as therapeutic agents as well as preservatives. We report the first computational study on the electronic effects of ortho-substituents in dendritic tri-phenolic antioxidants, comprising a common phenol moiety and two other phenol units with electron-donating or electron-withdrawing substituents. Among the three proposed antioxidant mechanisms, sequential proton loss electron transfer (SPLET) was found to be the preferred mechanism in methanol for the dendritic antioxidants based on calculations using Gaussian 16. We then computed the total enthalpy values by cumulatively running SPLET for all three rings to estimate electronic effects of substituents on overall antioxidant activity of each dendritic antioxidant and establish their structure–activity relationships. Our results show that the electron-donating o-OCH3 group has a beneficial effect while the electron-withdrawing o-NO2 group has a negative effect on the antioxidant activity of the dendritic antioxidant. The o-Br and o-Cl groups did not show any appreciable effects. These results indicate that electron-donating groups such as o-methoxy are useful for designing potent dendritic antioxidants while the nitro and halogens do not add value to the radical scavenging antioxidant activity. We also found that the half-maximal inhibitory concentration (IC50) values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) better correlate with the second step (electron transfer enthalpy, ETE) than the first step (proton affinity, PA) of the SPLET mechanism, implying that ETE is the better measure for estimating overall radical scavenging antioxidant activities.

scholarly journals Experimental and Computational Study on the Debenzylation of (2,4-dimethoxybenzyl)-protected 1,3-diazaoxindoles

2017 ◽  
Vol 61 (4) ◽  
pp. 264
Author(s):  
Eszter Kókai ◽  
Benjámin Kováts ◽  
Balázs Komjáti ◽  
Balázs Volk ◽  
József Nagy
Keyword(s):  
Reaction Mechanism ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Computational Study ◽  
Protecting Group ◽  
Electronic Effects ◽  
Triflic Acid ◽  
Drug Candidates ◽  
Insight Into

The introduction and removal of the 2,4-dimethoxybenzyl (DMB) moiety was studied in order to use it as a protecting group in the synthesis of diverse drug candidates containing the 1,3-diazaoxindole scaffold. The debenzylation of C(5)-unsubstituted and C(5)-isopropylidene-substituted 1,3-diazaoxindoles was investigated under various conditions. The DMB group could only be removed from the latter derivative using triflic acid. This observation can most likely be explained with electronic effects. In order to get a deeper insight into the reaction mechanism, quantum chemical calculations have been performed.

Hydrogen sensitivity – A systematic computational study of electronic effects

2007 ◽  
Vol 692 (21) ◽  
pp. 4473-4480 ◽  
Author(s):  
Peter H.M. Budzelaar ◽  
Betty B. Coussens ◽  
Nic Friederichs
Keyword(s):  
Computational Study ◽  
Electronic Effects

The bicyclo[2.1.1]hexan-2-one system: a new probe for the experimental and computational study of electronic effects in π-facial selectivity in nucleophilic additions

2001 ◽  
Vol 42 (48) ◽  
pp. 8527-8530 ◽  
Author(s):  
Goverdhan Mehta ◽  
S.Robindro Singh ◽  
Vanessa Gagliardini ◽  
U.Deva Priyakumar ◽  
G.Narahari Sastry
Keyword(s):  
Computational Study ◽  
Nucleophilic Additions ◽  
Electronic Effects ◽  
System A ◽  
Facial Selectivity

scholarly journals Computational study on 3D structure of L-aspartic acid and L-glutamic acid: molecular descriptors and properties

2016 ◽  
Vol 27 (1) ◽  
pp. 48-52 ◽  
Author(s):  
Amalia Stefaniu ◽  
Valeria Gabriela Savoiu ◽  
Irina Lupescu ◽  
Olga Iulian
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Complex Analysis ◽  
Molecular Descriptors ◽  
Computational Study ◽  
3D Structure ◽  
Chemical Properties ◽  
Electronic Effects ◽  
Mechanical Methods

Abstract The aim of this work is to provide a comprehensive and complex analysis of molecular descriptors and properties of two similar amino acids, L-Aspartic acid and L-Glutamic acid, using a software tool for calculations and properties predictions. As amino acids are model compounds for predicting the physical-chemical properties and behavior of biological, larger molecules as peptides or proteins, researches were focused on providing accurate mechanical calculations using: molecular/mechanical methods. Our study aims to initiate a linear scaling approach, by dividing a large system into small subsystems and performing the calculations for each, individually, then, embedding and correcting the information globally. The calculations were performed on the 3D structure of the studied amino acids that were first generated, as CPK model, and optimized by energy minimization. A comparative assay on their topological, molecular descriptors and properties was conducted, in vacuum and in water, using the Hartree-Fock model and second-order Møller-Plesset perturbation theory MP2 for predicting structure, energy and property calculations with Spartan’14 software. Values of molecular properties such as area, volume, polar surface area, polarizability, ovality, logP, dipole moment, HOMO-LUMO gap, distances and angles between atoms, were obtained. The results have been interpreted in terms of electronic effects of side chain groups, molecular deformability, steric factors and reactivity. This approach can be extended to other amino acids in order to predict protein-ligand interactions, important aspects in drug design studies and protein engineering.

A computational study of the interplay of steric and electronic effects in the stabilization of 1,3-(diamino)oxyallyls

2018 ◽  
Vol 1172 ◽  
pp. 3-7 ◽  
Author(s):  
Marc Devillard ◽  
Vianney Regnier ◽  
Monika Tripathi ◽  
David Martin
Keyword(s):  
Computational Study ◽  
Electronic Effects
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