نتایج جستجو برای: aromatic substitution
تعداد نتایج: 97354 فیلتر نتایج به سال:
In nucleophilic aromatic photosubstitution, just as in aromatic substitution in the ground state, substituents can have directing and activating effects. Four rules, which describe orientation of nucleophilic substitution in the excited state, can now be formulated. They are: (a) meta-activation by the nitro group (b) ortho/para-activation by the methoxy group (and probably also by other electr...
The facile and high yield synthesis of a new series of dibenzophenones in the presence of polyphosphoric acid (PPA) together with their cyclization to corresponding moni and dixanthones are described. The aromatic nucleophilic substitution of these new compounds are also studied.
Protonation of the highly reactive 1:l intermediate produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate by 2- hydroxyacetophenone leads to vinyltriphenylphosphonium salt, which undergoes aromatic electrophilic substitution reaction with the conjugate base to produce compounds 4,5, and 6 in 1 : 1.2:0.5 ratios
A bigger mechanistic picture of electrophilic aromatic substitution (EAS) is summarized and important “missing” postulates in EAS are unified.
Particular and rare examples of aromatic nucleophilic substitution are described as tele-substitution. Usually strong nucleophiles are involved and the entering group is introduced at a position distant from the expected leaving group. Examples of tele-substitution in various heteroaromatic systems are presented.
Some aryl and heteroaryl azido compounds were synthesized from the reaction of corresponding fluoro and chloro compounds with sodium azide in DMF as solvent and under various reaction conditions especially ultrasonic irradiation. Reaction of aromatic and heteroaromatic azido compound with thioacetic acid in the presence of sodium hydrogen carbonate and in methanol as solvent led to the differen...
A general, efficient, and sustainable method for nucleophilic aromatic substitution reactions in water using a cellulose-based additive was developed.
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 compounds were elucida...
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