scholarly journals Quantum chemistry study on the promoted reactivity of substituted cyclooctynes in bioorthogonal cycloaddition reactions

2021 ◽  
Vol 27 (1) ◽  
pp. 142-154
Author(s):  
Tayebeh Hosseinnejad ◽  
Marzieh Omrani-Pachin
Keyword(s):  
Activation Energy ◽  
Quantum Theory ◽  
Quantum Chemistry ◽  
Electron Density ◽  
Critical Points ◽  
Cycloaddition Reaction ◽  
Electronic Energy ◽  
The Other ◽  
Dipolar Cycloaddition ◽  
Topological Properties

Abstract In the present research, we focus on the energetics and electronic aspects of enhanced reactivity in the regioselective bioorthogonal 1,3-dipolar cycloaddition reaction of various substituted cyclooctynes with methyl azide, applying quantum chemistry approaches. In this respect, we assessed the structural and energetic properties of regioisomeric products and their corresponded transition states and calculated the reaction electronic energy changes and energy barriers through the cycloaddition pathways. The obtained results revealed that the trifluoromethyl substitution and fluorination of cyclooctynes lead to improved reactivity, in conjunction with increased exothermicity and decreased activation energy values. On the other hand, quantum theory of atoms in molecules computations were performed on some key bond and ring critical points that demonstrated the stabilizing topological properties of electron density and its derivatives upon trifluoromethyl substitution and fluorination of propargylic carbon of cyclooctynes which can be regarded as the essential origin of enhanced reactivity.

On the transferability of electron density in binary vanadium borides VB, V3B4 and VB2

2015 ◽  
Vol 71 (6) ◽  
pp. 777-787 ◽  
Author(s):  
Bürgehan Terlan ◽  
Lev Akselrud ◽  
Alexey I. Baranov ◽  
Horst Borrmann ◽  
Yuri Grin
Keyword(s):  
Quantum Theory ◽  
Crystal Structures ◽  
Electron Density ◽  
Critical Points ◽  
Atoms In Molecules ◽  
Model Systems ◽  
Suitable Model ◽  
Interatomic Distances ◽  
Systematic Analysis ◽  
A Charge

Binary vanadium borides are suitable model systems for a systematic analysis of the transferability concept in intermetallic compounds due to chemical intergrowth in their crystal structures. In order to underline this structural relationship, topological properties of the electron density in VB, V3B4 and VB2 reconstructed from high-resolution single-crystal X-ray diffraction data as well as derived from quantum chemical calculations, are analysed in terms of Bader's Quantum Theory of Atoms in Molecules [Bader (1990). Atoms in Molecules: A Quantum Theory, 1st ed. Oxford: Clarendon Press]. The compounds VB, V3B4 and VB2 are characterized by a charge transfer from the metal to boron together with two predominant atomic interactions, the shared covalent B—B interactions and the polar covalent B—M interactions. The resembling features of the crystal structures are well reflected by the respective B—B interatomic distances as well as by ρ(r) values at the B—B bond critical points. The latter decrease with an increase in the corresponding interatomic distances. The B—B bonds show transferable electron density properties at bond critical points depending on the respective bond distances.

Evolution thermique de N-oxydes D'ω-dialkylamino alcanols-1

1984 ◽  
Vol 49 (10) ◽  
pp. 2410-2414 ◽  
Author(s):  
Didier Barbry ◽  
Bruno Hasiak
Keyword(s):  
Hydrogen Atom ◽  
Transition State ◽  
Tertiary Amine ◽  
Amino Alcohol ◽  
Cycloaddition Reaction ◽  
Reduction Process ◽  
The Other ◽  
Dipolar Cycloaddition ◽  
Oxidation Reduction ◽  
Planar Transition

The thermolysis of ω-dimethylamino-1-alkanol N-oxides affords ω-hydroxy-1-alkenes with dimethylhydroxylamine in good yields. The other basic products ( amino alcohol and isoxazolidine) involve oxidation-reduction process between the tertiary amine N-oxide and dimethylhydroxylamine, followed by 1,3-dipolar cycloaddition reaction. Pyrolysis of 5-piperidino-1-pentanol N-oxide proceeds on a path similar to the N-dimethyl compounds. The elimination of an hydrogen atom of the heterocycle does not occur: the preferred planar transition state cannot be attained because of the steric requirements of the ring.

Synthetic approaches towards bisspiro[naphthalene-2(1H),3′-(3H)pyrazol]-1-one-containing compounds

2006 ◽  
Vol 60 (3) ◽  
Author(s):  
A. Girgis ◽  
F. Osman ◽  
F. El-Samahy ◽  
I. Ahmed-Farag
Keyword(s):  
Cycloaddition Reaction ◽  
The Other ◽  
Dipolar Cycloaddition ◽  
Hydrazonoyl Chlorides ◽  
Other Hand ◽  
Synthetic Approaches

Abstract1,3-Dipolar cycloaddition reaction of bis{[4-(3,4-dihydro-(2H)-naphthalen-1-oxo-2-yl)methyl-idenephenyl]oxy}alkanes with nitrilimines (generated in situ by triethylamine dehydrohalogenation of the corresponding hydrazonoyl chlorides) in refluxing dry benzene afforded a mixture of monocycloadduct and dicycloadduct products in high regioselectivity. On the other hand, reaction of bis{[2-(3,4-dihydro-(2H)-naphthalen-1-oxo-2-yl)methylidenephenyl]oxy}alkanes with nitrilimines gave the corresponding dicycloadducts as the only isolable regioisomers.

Topological properties of the electronic structures of the reactants, transition states, and products of the reactions of the hydroxyl radical with the series C2HnF6−n, n = 1–6

1996 ◽  
Vol 74 (6) ◽  
pp. 786-800 ◽  
Author(s):  
Jaime M. Martell ◽  
James B. Tee ◽  
Russell J. Boyd
Keyword(s):  
Hydroxyl Radical ◽  
Electron Density ◽  
Critical Points ◽  
Population Analysis ◽  
Transition States ◽  
Reaction Centre ◽  
Topological Properties ◽  
Mulliken Population ◽  
Dissociation Energies ◽  
Reaction Proceeds

Properties of the bond critical points, including the electron density and its Laplacian, and distances to bonded nuclei, for all species (reactants, transition states, and products) in the reactions of the hydroxyl radical with the series C2HnF6−nn = 1–6 were calculated using Bader's atoms-in-molecules methodology. The electron density and its Laplacian at the bond critical points correlate with bond strength, as measured by bond dissociation energies. The positions of the bond critical points vary with the electronegativity of surrounding atoms. Charge development in the course of the reactions was monitored using Mulliken population analysis at the HF/6-31G(d), HF/6-311G(d,p)//HF/6-31G(d), MP2/6-311G(d,p)//HF/6-31G(d), and HF/6-311G(d,p)//MP2/6-31G(d,p) levels of theory, and natural population analysis and Bader population analysis at the highest common level of theory, MP2/6-311G(d,p)//HF/6-31G(d). In general, there is a buildup of charge in the transition states, concentrated near the reaction centre, which dissipates somewhat as the reaction proceeds to products. The description of charge transfer varies somewhat with the three methods. Key words: topological properties, atomic charges, charge development, reactions of the hydroxyl radical with fluorinated ethanes.

New Pyrrolo[1,2-b]pyridazine Derivatives by 1,3-Dipolar Cycloaddition of Mesoionic Oxazolopyridazinone

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Miron Teodor Caproiu ◽  
Florea Dumitrascu ◽  
Mino R. Caira
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Pyridazine Derivatives ◽  
New Compounds

New pyrrolo[1,2-b]pyridazine derivatives 8a-f were synthesized by 1,3-dipolar cycloaddition reaction between mesoionic 1,3-oxazolo[3,2-b]pyridazinium-2-oxides and diethyl or diisopropyl acetylenedicarboxylate as alkyne dipolarophiles. The structures of the new compounds were assigned by elemental analysis and NMR spectroscopy.

Copper-catalyzed Convenient Synthesis and SAR Studies of Substituted-1,2,3-triazole as Antimicrobial Agents

2018 ◽  
Vol 16 (1) ◽  
pp. 3-10
Author(s):  
Aniket P. Sarkate ◽  
Kshipra S. Karnik ◽  
Pravin S. Wakte ◽  
Ajinkya P. Sarkate ◽  
Ashwini V. Izankar ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antifungal Activity ◽  
Antimicrobial Agents ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
One Pot ◽  
Triazole Derivatives ◽  
Sar Studies ◽  
Convenient Synthesis ◽  
Antibacterial And Antifungal

Background:A novel copper-catalyzed synthesis of substituted-1,2,3-triazole derivatives has been developed and performed by Huisgen 1,3-dipolar cycloaddition reaction of azides with alkynes. The reaction is one-pot multicomponent.Objective:We state the advancement and execution of a methodology allowing for the synthesis of some new substituted 1,2,3-triazole analogues with antimicrobial activity.Methods:A series of triazole derivatives was synthesized by Huisgen 1,3-dipolar cycloaddition reaction of azides with alkynes. The structures of the synthesized compounds were elucidated and confirmed by 1H NMR, IR, MS and elemental analysis. All the synthesized compounds were tested for their antimicrobial activity against a series of strains of Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and against the strains of Candida albicans, Aspergillus flavus and Aspergillus nigar for antifungal activity, respectively.Results and Conclusion:From the antimicrobial data, it was observed that all the newly synthesized compounds showed good to moderate level of antibacterial and antifungal activity.

Polar Diels-Alder Reactions Under Microwave Irradiation Employing Different Heterocyclic Compounds as Electrophiles

2019 ◽  
Vol 16 (6) ◽  
pp. 527-543 ◽  
Author(s):  
Pedro M.E. Mancini ◽  
Carla M. Ormachea ◽  
María N. Kneeteman
Keyword(s):  
Organic Synthesis ◽  
Heterocyclic Compounds ◽  
Ionic Conduction ◽  
Theoretical Calculations ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
The Other ◽  
Conventional Heating ◽  
Protic Ionic Liquids ◽  
Solvent Free Conditions

During the last twenty years, our research group has been working with aromatic nitrosubstituted compounds acting as electrophiles in Polar Diels-Alder (P-DA) reactions with different dienes of diverse nucleophilicity. In this type of reaction, after the cycloaddition reaction, the nitrated compounds obtained as the [4+2] cycloadducts suffer cis-extrusion with the loss of nitrous acid and a subsequent aromatization. In this form, the reaction results are irreversible. On the other hand, the microwave-assisted controlled heating become a powerful tool in organic synthesis as it makes the reaction mixture undergo heating by a combination of thermal effects, dipolar polarization and ionic conduction. As the Diels-Alder (D-A) reaction is one of the most important process in organic synthesis, the microwave (MW) irradiation was applied instead of conventional heating, and this resulted in better yields and shorter reaction times. Several substituted heterocyclic compounds were used as electrophiles and different dienes as nucleophiles. Two experimental situations are involved: one in the presence of Protic Ionic Liquids (PILs) as solvent and the other under solvent-free conditions. The analysis is based on experimental data and theoretical calculations.

Rapid Access to Novel 1,2,3-Triazolo-Heterocyclic Scaffolds via Tandem Knoevenagel Condensation/Azide–Alkyne 1,3-Dipolar Cycloaddition Reaction in One Pot

2014 ◽  
Vol 16 (9) ◽  
pp. 466-477 ◽  
Author(s):  
Ram Awatar Maurya ◽  
Praveen Reddy Adiyala ◽  
D. Chandrasekhar ◽  
Chada Narsimha Reddy ◽  
Jeevak Sopanrao Kapure ◽  
...  
Keyword(s):  
Knoevenagel Condensation ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
One Pot ◽  
Rapid Access

Synthesis of novel isoxazole-benzoquinone hybrids via 1,3-dipolar cycloaddition reaction as key step

2012 ◽  
Vol 53 (32) ◽  
pp. 4108-4113 ◽  
Author(s):  
P. Ravi Kumar ◽  
Manoranjan Behera ◽  
K. Raghavulu ◽  
A. Jaya Shree ◽  
Satyanarayana Yennam
Keyword(s):  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition
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