نتایج جستجو برای: aromatic substitution
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Figure 1: Directed aromatic functionalization methods. The title of this Thematic Series brings to the minds of most organic chemists the beautifully logical aromatic electrophilic substitution (SEAr) [1-5] and, to a lesser extent, nucleophilic aromatic substitution (SNAr) [2,6,7] reactions as taught to many generations of students in their first organic chemistry courses [8] (Figure 1). Being ...
Lignans bind to sex hormone-binding globulin (SHBG). The lignan with the highest binding affinity is (+/-)-3,4-divanillyltetrahydrofuran. In a double Stobbe condensation--without use of protecting groups--a wide variety of lignans with different substitution pattern in the aromatic and aliphatic part of the molecule was synthesized. These lignans were tested in a SHBG-binding assay which allowe...
The validity of calculated NMR shifts to predict the outcome of electrophilic aromatic substitution reactions on different heterocyclic compounds has been examined. Based on an analysis of >130 literature examples, it was found that the lowest predicted (13)C and/or (1)H chemical shift of a heterocycle correlates qualitatively with the regiochemical outcome of halogenation reactions in >80% of ...
A metal-free oxidative decarbonylative coupling of aromatic aldehydes with electron-rich or electron-deficient arenes to produce biaryl compounds was developed. This novel coupling was proposed to proceed via a non-chain radical homolytic aromatic substitution (HAS) type mechanism, based on the substrate scope, ortho-regioselectivity, radical trapping experiments and DFT calculation studies. Wi...
Some oxime ether derivatives of α-ionone (4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one) have been synthesized. Reaction of 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-ketoxime with various chloro and fluoro aromatic and hetero aromatic compounds gave the corresponding oxime ether derivatives via aromatic nucleophilic substitution (SNAr). The structures of these co...
A novel and unprecedented formation of η(4)-(vinylketene)iron complexes from η(4)-(diene)iron complexes is described herein. Treatment of η(4)-(diene)iron complexes with a Lewis acid such as GaCl3 or AlCl3 in the presence of aromatic compounds under a CO atmosphere affords η(4)-(vinylketene)iron complexes via electrophilic aromatic substitution.
Variable scan rate (0.1-500 V s(-1)) cyclic voltammetry experiments were performed on a series of model tocopherol (vitamin E) compounds with differing degrees of methyl substitution around the aromatic (phenolic) ring. alpha-Tocopherol, with a fully methylated aromatic ring, produced stable phenoxonium cations upon oxidation in CH3CN, and was modeled via an ECE mechanism (where "E" represents ...
In this paper, the application of the double radical nucleophilic aromatic substitution (SRN1) in various dihalogenated, mostly diiodinated, π-conjugated systems as a tool for qualitatively estimating their π-conjugation is described. This approach uses electron delocalisation as a measure of π-conjugation. Electron injection into the π-system is achieved via reaction of an intermediate aryl ra...
In this paper, the application of the double radical nucleophilic aromatic substitution (SRN1) in various dihalogenated, mostly diiodinated, p-conjugated systems as a tool for qualitatively estimating their pconjugation is described. This approach uses electron delocalisation as a measure of p-conjugation. Electron injection into the p-system is achieved via reaction of an intermediate aryl rad...
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