Nucleophilic aromatic substitution reactions of 4-chloroquinazoline toward aniline and hydrazine were used as a model system to experimentally show that a substrate bearing heteroatoms on the aromatic ring as substituent is able to establish intramolecular hydrogen bond which may be activated by the reaction media and/or the nature of the nucleophile.
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http://dx.doi.org/10.3389/fchem.2018.00509 | DOI Listing |
Molecules
June 2024
Institute of Organic Chemistry and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland.
Regioselectivity and the molecular mechanism of the [3+2] cycloaddition reaction between nitro-substituted formonitrile N-oxide and electron-rich alkenes were explored on the basis of the wb97xd/6-311+G(d) (PCM) quantum chemical calculations. It was established that the thermodynamic factors allow for the formation of stable cycloadducts along all considered models. The analysis of the kinetic parameters of the main processes show that all [3+2] cycloadditions should be realized with full regioselectivity.
View Article and Find Full Text PDFOrg Lett
June 2023
Institute of Technology of Organic Chemistry, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena str. 3, Riga LV-1048, Latvia.
Terminal alkynes with a silyl group at the propargylic position upon activation with electrophiles such as -bromosuccinimide undergo ()-selective 1,2-silyl group migration. Subsequently, an allyl cation is formed that is intercepted by an external nucleophile. This approach provides allyl ethers and esters with stereochemically defined vinyl halide and silane handles for further functionalization.
View Article and Find Full Text PDFToxicology
April 2019
The Chemical Synthesis & Biology Core Facility, Albert Einstein College of Medicine, Bronx, NY, United States.
Electron-deficient chemicals (electrophiles) react with compounds that have one or more unshared valence electron pairs (nucleophiles). The resulting covalent reactions between electrophiles and nucleophiles (e.g.
View Article and Find Full Text PDFFront Chem
October 2018
Centro de Química Médica, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile.
Nucleophilic aromatic substitution reactions of 4-chloroquinazoline toward aniline and hydrazine were used as a model system to experimentally show that a substrate bearing heteroatoms on the aromatic ring as substituent is able to establish intramolecular hydrogen bond which may be activated by the reaction media and/or the nature of the nucleophile.
View Article and Find Full Text PDFJ Am Chem Soc
January 2016
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom.
The activation of the SN2 reaction by π systems is well documented in textbooks. It has been shown previously that this is not primarily due to classical (hyper)conjugative effects. Instead, π-conjugated substituents enhance favorable substrate-nucleophile electrostatic interactions, with electron-withdrawing groups (EWG) on the sp(2) system leading to even stronger activation.
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