Aromatic N-substitution Research Articles

Reaction of phenylhydrazines with arenes in the presence of aluminium trichloride

Phenylnitrenium ions are generated from phenylhydrazines by treatment with AlCl3. Reaction of a phenylnitrenium ion with arenes results in both aromatic N-substitution and C-substitution. In contrast, an N-methylphenylnitrenium ion undergoes exclusively aromatic C-substitution. Reaction of a phenylnitrenium ion with arenes present only in slight excess produces anilinated products in moderate to good yields.

Reaction of aromatic azides with strong acids: formation of fused nitrogen heterocycles and arylamines

We describe in this paper the action of trifluoroacetic acid, trifluoromethanesulfonic acid and aluminum chloride upon ortho-substituted aryl azides to form indoles, azepines and arylamines in good yields. The protonated azides lose nitrogen to form arylnitrenium ion intermediates which undergo intramolecular aromatic N-substitution. The acid decomposition of aryl azides is compared with reported thermolyses.

Novel generation of parent, alkyl, dialkyl and alicyclic nitrenium ions in photolyses of pyridinium, quinolinium, bipyridinium and phenanthrolinium salts and aromatic N-substitution by nitrenium ions

Download options Please wait... Article information DOI https://doi.org/10.1039/P29910000847 Article type Paper Download Citation J. Chem. Soc., Perkin Trans. 2, 1991, 847-855 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Novel generation of parent, alkyl, dialkyl and alicyclic nitrenium ions in photolyses of pyridinium, quinolinium, bipyridinium and phenanthrolinium salts and aromatic N-substitution by nitrenium ions H. Takeuchi, S. Hayakawa, T. Tanahashi, A. Kobayashi, T. Adachi and D. Higuchi, J. Chem. Soc., Perkin Trans. 2, 1991, 847 DOI: 10.1039/P29910000847 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Hiroshi Takeuchi Satoshi Hayakawa Toshikatsu Tanahashi Atsushi Kobayashi Taki Adachi Dai Higuchi

Inter- and intra-molecular aromatic N-substitution by arylnitrenium–aluminium chloride complexes generated from aryl azides in the presence of aluminium chloride

Reactions of phenyl azide with aromatic compounds (i.e. benzene, toluene, ethylbenzene, cumene, anisole, and bromobenzene) in the presence of AlCl3 gave diarylamines, whereas those of phenyl azides with an electron-donating group such as Me and OMe yield little of the corresponding diarylamines (tar formation takes place). The reaction of 4-nitrophenyl azide with benzene in the presence of AlCl3 gave 4-nitrophenyl(phenyl)amine and a C-substitution product, 2-amino-5-nitrobiphenyl. Decomposition of 2-azidophenyl(phenyl)methane and 2-azidobiphenyls in CH2Cl2 in the presence of AlCl3 underwent an N-cyclization to afford 9,10-dihydroacridine and carbazoles, respectively, in good yields. The kinetic data on the decomposition of aryl azides and a Hammett plot (with ρ–6.0) for the formation of diarylamines suggest that the products are formed by an aromatic N-substitution of arylnitrenium–AlCl3 complexes via azide–AlCl3 complexes. We further argue the character of arylnitrenium–AlCl3 complexes.

Aliphatic CH, N-insertion versus aromatic N-substitution in the reaction of arylnitrenium-boron trifluoride complexes with methylated benzenes

The boron trifluoride promoted decomposition of a number of substituted phenyl azides in toluene, para -xylene, meta -xylene or mesitylene at 60°C, leads preferentially to N -benzylamines or diarylamines depending on both ring substituent effect and nucleophilic character of the solvent.

N- and C-Attacks of phenylnitrenium ions generated from phenyl azides in the presence of trifluoroacetic acid and/or trifluoromethanesulphonic acid

Phenylnitrenium ions were generated from phenyl azides in the presence of trifluoroacetic acid (TFA) and/or trifluoromethanesulphonic acid (TFSA). Unsubstituted phenylnitrenium ions and those with an electron-withdrawing group such as NO2 or CN undergo aromatic N-substitution, whereas those with an electron-donating group such as Me, OMe, CH2Ph, or Ph undergo C-substitution, hydrogen abstraction, and tar formation. The special character of TFA and TFSA as compared with other acids is discussed.

Electrophilic aromatic N-substitution by ethoxycarbonylnitrenium ion generated from ethyl azidoformate in the presence of trifluoroacetic acid

Thermal reactions of ethyl azidoformate with aromatic compounds in the presence of trifluoroacetic acid (TFA) gave ethyl N-arylcarbamates. Toluene, nitrobenzene, or naphthalene was selectively attacked on the ortho- and para-positions, on the ortho- and meta-positions, or on the 1- and 2-positions, respectively. The yields were ca. twice as high as those for thermolysis (a nitrene–azepine route) in the absence of TFA with the subsequent addition of TFA at room temperature. The positional selectivities for toluene and naphthalene were lower for the former thermolysis than for the latter. The reactivity of cyclohexane or toluene relative to benzene was greater in the latter thermolysis than the former. A Hammett plot with ρ–1.7 was obtained for the formation of ethyl N-arylcarbamates in the former thermolysis in TFA–nitrobenzene (8 : 2 v/v); the value was more negative than that (–1.32) for the disappearance of substituted benzenes in the reaction with ethoxycarbonylnitrene. The results suggest that the thermolysis in the presence of TFA involves an electrophilic aromatic N-substitution by ethoxycarbonylnitrenium ion.

Aromatic substitution by phenylnitrenium and naphthylnitrenium ions formed from phenyl azide and 1-azidonaphthalene in the presence of trifluoromethanesulphonic acid

Aromatic N-substitution by phenylnitrenium ions generated from phenyl azide in the presence of a catalytic amount of trifluoromethanesulphonic acid gave diarylamines (in especially good yield in the reactions with biphenyl or naphthalene), whereas naphthylnitrenium ions from 1-azidonaphthalene react with benzene to afford a C-substitution product, 1-amino-4-phenylnaphthalene.

Aromatic N-substitution by phenylnitrenium ion. Reaction of phenyl azide with aromatics in the presence of trifluoroacetic acid

Reaction of phenyl azide with aromatics in the presence of trifluroacetic acid gave diarylamines by an electrophilic N-substitution of the phenylnnitrenium ion onto aromatics.

Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones VIII. Synthesis of N,N‐disubstituted 4‐amino‐3‐chloro‐6‐phenyl‐2H‐pyran‐2‐ones

AbstractThe dipolar 1,4‐cycloaddition of dichloroketene to N,N‐disubstituted 3‐amino‐1‐phenyl‐2‐propene‐1‐onesled directly to N,N‐disubstituted 4‐amino‐3‐chloro‐6‐phenyl‐2H‐pyran‐2‐ones only in the case of an usual aliphatic N,N‐disubstitution. In the case of partial or full aromatic N‐substitution, N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4‐dihydro‐6‐phenyl‐2H‐pyran‐2‐ones were instead obtained, which were dehydrochlorinated with DBN to the corresponding 4‐amino‐3‐chloro‐6‐phenyl‐2H‐pyran‐2‐ones.

ChemInform Abstract: REACTION OF DICHLOROKETENE AND SULFENE WITH N,N‐DISUBSTITUTED 6‐AMINOMETHYLENE‐5,6,8,9‐TETRAHYDRO‐7H‐BENZOCYCLOHEPTEN‐7‐ONES. SYNTHESIS OF 5H‐BENZO(5,6)CYCLOHEPTA(2,1‐B)PYRAN AND 5H‐BENZO(5,6)CYCLOHEPTA(1,2‐E)‐1,2‐OXATHIIN DERIVATIVES

AbstractDas Keton (I) wird mit Ameisensäureester zum Formyl‐keton (II) und dann mit Aminen zu den Enamin‐ketonen (III) umgesetzt.

Reaction of dichloroketene and sulfenc with N,N‐disubstituted 2‐aminomethylene‐1 ‐indanones. Synthesis of indeno[ 1,2‐b ] pyran and lndeno[2,l‐e] ‐1,2‐oxathiin derivatives

AbstractThe 1,4‐cycloaddition of dichloroketene to N,N‐disubstituted 2‐aminomethylcnc‐l‐indanones afforded N,N‐disubstituted 4‐ainino‐3,3‐dichloro‐3,4‐dihydro‐2‐oxoindeno[1,2‐b ]pyrans only in the case of full or partial aromatic N‐substitution. The diphenylamino adduct gave 3‐chloro‐4‐diphenylamino‐2‐oxoindeno[ 1,2‐b]pyran by dehydrochlorination with DBN. The 1,4‐cycloaddition with sulfene occurred only in the case of 2‐diethylaininomethylene‐1‐indanone to give 4‐diethylamino‐3,4‐dihydroindeno[2, 1‐e]‐1,2‐oxathiin 2,2‐dioxide, a derivative of a new hetero‐cyclic system.