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With the use of Hartree-Fock and DFT methods we demonstrated that for the benzene derivatives with the substituents Me, Et, Pr, i-Pr, t-Bu, CF, F, and Cl π-complexes are more favorable by energy, whereas with the substituents CHO, MeCO, PhCO, CN, NO, and NO n-complexes are more feasible. The affi nity of aromatic compounds to the nitrosonium-cation (A+) at the formation of the π-complexes grows with the growing donor character of the substituents in the ring and with their number. The best agreement between the calculated and experimental A+ values for benzene was obtained with the use of RI-MP2/L1 method. [ABSTRACT FROM AUTHOR]

Reactions of N-fluorobis(phenylsulfonyl)amine with naphthalene, 1-methylnaphthalene, phenanthrene, anthracene, and pyrene without solvent were investigated. Sometimes the fluorination of aromatic compounds with N-fluorobis(phenylsulfonyl)amine without solvent proceeded more selectively than at the use of fluorinating reagents in solution. [ABSTRACT FROM AUTHOR]

Reactions of N-fluorobenzenesulfonimide with methylbenzenes, phenols, and phenol ethers were studied under solvent-free conditions. The rate constant ratio for the reactions with mesitylene and durene indicates polar mechanism of the process. Solvent-free fluorination of aromatic compounds with N-fluorobenzenesulfonimide in some cases is more selective than reactions with other N-F reagents in a solvent. [ABSTRACT FROM AUTHOR]

According to the 1H and 13C NMR data, triptycene reacts with nitrosonium tetrachloroaluminate to form positively charged π-complexes with one and two nitrosonium ions, which are rapidly (on the NMR time scale) converted into each other. DFT quantum-chemical calculations with Λ02 basis set indicated higher stability of singly charged complexes relative to doubly charged. Addition of three nitrosonium ions to triptycene molecule is unfavorable from the energy viewpoint. [ABSTRACT FROM AUTHOR]

Kinetic isotope effects H/D in electrophilic fluorination of aromatic compounds with NF-reagents were investigated. The small values of k H/ k D (0.86–1.00) are in agreement with the polar reaction mechanism where the Wheland complex decomposition is not the limiting stage. The fluorination of 1,3,5-trideuterobenzene was established by 1H and 19F NMR spectroscopy to occur with a 1,2-migration of a hydrogen (deuterium) atom. The analysis of Brown-Stock relationship demonstrated that the activity of NF-reagents exceeded that of many known electrophilic systems including halogenation, but it was essentially less than the activity of elemental fluorine. [ABSTRACT FROM AUTHOR]

The review summarizes and analyzes published data on electrophilic aromatic substitution reactions performed in ionic liquids. [ABSTRACT FROM AUTHOR]

Published data on direct electrophilic amination of aromatic compounds are summarized and analyzed on the basis of nitrenium ion properties. [ABSTRACT FROM AUTHOR]

The article reports that N-Amino-substituted azinium salts are widely used as reagents for amination of arenes and synthesis of imines and various heterocyclic and other compounds. In the synthesis of N-amino derivatives of azines having several heteroatoms, the problem arises as to whether the amination will occur at one or another nitrogen atom. 1,10-Phenanthroline derivatives are among promising models for studying regioselectivity in the amination of azines. The present study elucidates electronic factors determining regioselectivity in the amination of 1,10-phenanthroline derivatives with O-mesitylsulfonylhydroxylamine.

The article focuses on the solvent effects in the electrophilic amination of mesitylene with the system NaN3-AlCl3-HCl. Substitution of hydrogen in an aromatic ring by amino group is usually a two-step process which implies introduction of a temporary functional group or atom. In the recent years, an interest has grown in direct electrophilic amination of arenes. A convenient reagent for direct electrophilic amination is sodium azide that is used under conditions of acid catalysis. Researchers studied electrophilic amination of benzene and its derivatives with the system NaN3-AlCl3-HCl.

The article presents a study which aims to examine the effect of direct amination of arenes with sodium azide in trifluoromethanesulfonic acid. It mentions that the chemicals were mixed together and were subjected to ultrasonic irradiation. It relates that the result of the research revealed that electrophilic amination can be performed successfully by using stoichoimetric reactants.

The article presents a study to examine the possibility of using ionic liquids as solvents in electrophilic amination of arenes. The use of ionic liquids as a medium for organic reactions has attracted increasing interest. Ionic liquids are considered to be green solvents which possess a combination of unique properties, such as low volatility and toxicity and high thermal and chemical stability and polarity. The latter property makes them especially attractive for carrying out heterolytic reactions, in particular electrophilic aromatic substitution. Up to now, ionic liquids have been used in alkylation and acylation.