The question of the reversibility in the aminomercuration of olefins. Synthesis of N-aryl-9-azabicyclo[4.2.1]and [3.3.1] nonanes by aminomercuration of cis-cis- 1.5-cyclooctadiene

The aminomercuration of olefins is found to be a reversible or irreversible process depending on the nature of the mercury(II) salt employed. This is in clear contrast with the mechanism of oxymercuration reactions. A selective synthesis of the title compounds is described by kinetically or thermodinamically controlled aminomercuration of cis-cis-1,5-cycloctadiene.     

Semiconductor-catalyzed photooxygenation of aromatic olefins

Irradiation of semiconductors (TiO₂ and CdS) suspended in organic solvents containing 1,1-diphenylethylene and its derivatives under oxygen afforded the corresponding epoxides and benzophenone. A possible mechanism is discussed.     

The reaction of pentachloropyridine with aromatic amines

The reaction of pentachloropyridine with aromatic amines in dimethylformamide in the presence of sodium carbonate leads to 4-arylaminotetrachloropyridines. The product of the reaction of pentachloropyridine with aniline in pyridine is 4-amino-2,3,5,6-tetrachloropyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 7, pp. 963–965, July, 1970.     

The amidoalkylation of aromatic compounds and olefins with 5-alkoxyhydantoins

5-Butoxyhydantoin (2a), 3-benzyl-5-methoxyhydantoin (2b) and 3-p-chlorophenyl-5-methoxy hydantoin (2c) were found to react, in the presence of an acid catalyst, with aromatic compounds and olefins to give 5-arylhydantoin (3) and 5-alkylhydantoins with an unsaturated side chain. Isomers which differ in the location of the double bond (4,5,6) as well as cis-trans isomers were isolated and characterized.     

Structure and reactivity of aromatic amines

Summary A systematic study has been made of the effect of structural factors showing up in the reactivity of mononuclear and polynuclear aromatic acids.     

The determination of substituted aromatic amines in water and sediment samples

Summary Certain substituted aromatic amines (anilines and benzidines) are known to possess high toxicological potential. They are classical environmental pollutants by virtue of their high degree of water solubility and the large amounts produced annually in the chemical industry for the synthesis of dyes, pesticides and pharmaceuticals.The present paper describes a method for the determination of at least thirty-one of these compounds at lower g/l or g/kg (ppb) ranges in water or sediment samples.Capillary column gas chromatography is employed with NFI- or MS-detection.Dedicated clean-up procedures are described for the substituted anilines and benzidines in aqueous and sedimentary matrices. In addition, quality assurance aspects of the individual single component identification by NFI- or MS-detection are discussed.

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Bestimmung substituierter, aromatischer Amine in Wasser- und Sedimentproben

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Dedicated to Prof. Dr. W. Fresenius on the occasion of his 75th birthday     

Analysis of heterocyclic aromatic amines

Heterocyclic aromatic amines are formed in protein and amino acid-rich foods at temperatures above 150 °C. Of more than twenty heterocyclic aromatic amines identified ten have been shown to have carcinogenic potential. As nutritional hazards, their reliable determination in prepared food, their uptake and elimination in living organisms, including humans, and assessment of associated risks are important food-safety issues. The concentration in foods is normally in the low ng g⁻¹ range, which poses a challenge to the analytical chemist. Because of the complex nature of food matrixes, clean-up and enrichment of the extracts are also complex, usually involving both cation-exchange (propylsulfonic acid silica gel, PRS) and reversed-phase purification. The application of novel solid-phase extraction cartridges with a wettable apolar phase combined with cation-exchange characteristics simplified this process—both the polar and apolar heterocyclic aromatic amines were recovered in one fraction. Copper phthalocyanine trisulfonate bonded to cotton (“blue cotton”) or rayon, and molecular imprinted polymers have also been successfully used for one-step sample clean-up. For analysis of the heterocyclic aromatic amines, liquid chromatography with base-deactivated reversed-phase columns has been used, and, recently, semi-micro and capillary columns have been introduced. The photometric, fluorimetric, or electrochemical detectors used previously have been replaced by mass spectrometers. Increased specificity and sub-ppb sensitivities have been achieved by the use of the selected-reaction-monitoring mode of detection of advanced MS instrumentation, for example the triple quadrupole and Q-TOF instrument combination. Gas chromatography, also with mass-selective detection, has been used for specific applications; the extra derivatization step needed for volatilization has been balanced by the higher chromatographic resolution.     

Analysis of aromatic amines in cigarette smoke

A method for the analysis of o-toluidine, o-anisidine, 2-naphthylamine, and 4-aminobiphenyl in cigarette mainstream smoke has been developed, which combines the sensitivity of their pentafluoropropionyl (PFP) derivatives in negative ion chemical ionization (NICI) mode with the selectivity of the gas chromatography/tandem mass spectrometry (GC/MS/MS) technique. The use of four deuterated analogues as internal standards along with the application of the standard addition method results in accurate and precise results; the interday precision for the aromatic amines was 3-10% and the accuracy ranged from 97-100%. This method was applied to two American-blend University of Kentucky reference cigarettes, eight American-blend market cigarettes, a bright (flue-cured) tobacco cigarette, and an electrically heated cigarette smoking system (EHCSS). For the American-blend cigarettes there was a linear correlation between aromatic amine yields and mainstream smoke 'tar' ('tar' = total particulate matter - (nicotine + water)), whereas the bright tobacco cigarette and the EHCSS demonstrated significantly lower aromatic amine yields on an equal 'tar' basis. The results support the hypothesis that the nitrogen content of the tobacco, and above all the cigarette combustion temperature, are determining factors for the yields of aromatic amines in smoke.     

Effect of solvents on the electrochemistry of olefins and aromatic molecules

Cyclic voltammetry and electrolysis studies were carried out in dimethyl sulfoxide, diglyme and liquid ammonia. The depolarizers were diethyl fumarate, ethyl cinnamate, stilbene and anthracene. The reduction reactions were carried out in the presence of organic halides, phenol, acids and water. The rates of the reactions were measured. The main solvent effect was noticed with water which reacts 100 times faster in diglyme than in liquid ammonia or DMSO. The results of electrolytic experiments with two reactants simultaneously were compared with those predicted from the kinetic data.     

Regioselective one-pot bromination of aromatic amines

[reaction: see text] Treatment of aniline with n-butyllithium and then trimethyltin chloride gave the tin amide (PhNH-SnMe(3)) in situ. Without isolation of the tin amide, reaction with bromine and workup with aqueous fluoride ion gave p-bromoaniline in 76% yield, with no dibromoaniline or o-bromoaniline. Application of this sequence to 11 different aromatic amines gave selective bromination in 36-91% yields, without formation of dibromides. This constitutes a good general method for the regioselective bromination of aromatic amines.     

Fungal bioremediation of pollutant aromatic amines

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The gas phase structure of some protonated and ethylated aromatic amines

The fundamental processes of protonation and ethylation, occurring in a methane chemical ionization source, have been investigated for a variety of aromatic amines. The positions of protonation and ethylation on the substrate amines were determined by generating isomeric ions either by protonation of neutral ethyl substituted amines or by ethylation of the amines themselves. The product ions were investigated for structural differences via collision induced dissociation and subsequent analysis via mass analysed ion kinetic energy spectrometry. Similarities and differences between mass analysed ion kinetic energy/collision induced dissociation spectra of these isomeric ions were used to determine protonation and ethylation sites for imidazole, benzimidazole, indazole, pyrrole, pyridine and aniline.