- Nitrosation of arenes with nitrosonium ethyl sulfate
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Nitrosonium ethyl sulfate reacts with O-alkylphenols and N,N-dialkylanilines to give the corresponding 4-nitrosoarenes. The reaction is not accompanied by side processes characteristic of common nitrosating agents. Diazotization of primary aromatic amines with nitrosonium ethyl sulfate yields stable diazonium salts, which are promising reagents for organic synthesis.
- Zyk,Nesterov,Khlobystov,Zefirov
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- Insight into the preferential N-bindingversusO-binding of nitrosoarenes to ferrous and ferric heme centers
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Nitrosoarenes (ArNOs) are toxic metabolic intermediates that bind to heme proteins to inhibit their functions. Although much of their biological functions involve coordination to the Fe centers of hemes, the factors that determine N-binding or O-binding of these ArNOs have not been determined. We utilize X-ray crystallography and density functional theory (DFT) analyses of new representative ferrous and ferric ArNO compounds to provide the first theoretical insight into preferential N-bindingversusO-binding of ArNOs to hemes. Our X-ray structural results favored N-binding of ArNO to ferrous heme centers, and O-binding to ferric hemes. Results of the DFT calculations rationalize this preferential binding on the basis of the energies of associated spin-states, and reveal that the dominant stabilization forces in the observed ferrous N-coordination and ferric O-coordination are dπ-pπ* and dσ-pπ*, respectively. Our results provide, for the first time, an explanation whyin situoxidation of the ferrous-ArNO compound to its ferric state results in the observed subsequent dissociation of the ligand.
- Abucayon, Erwin G.,Chu, Jia-Min,Ayala, Megan,Khade, Rahul L.,Zhang, Yong,Richter-Addo, George B.
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- NO2/H3BO3 as an effective nitrosonium source for electrophilic aromatic nitrosation under MW-promoted solvent-free conditions
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[Bmim]NO2/H3BO3 was used as a nitrosonium source for the efficient synthesis of nitrosoarenes. The reaction was accomplished under MW irradiation at 60 W in a solventless system. Side processes such as oxidation or dealkylation were not observed during the nitrosation of alkyl phenyl ethers in the presence of this new reagent. The satisfactory results were obtained with very short reaction time, simplicity in the experimental procedure and good to excellent yields.
- Valizadeh, Hassan,Gholipour, Hamid
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experimental part
p. 963 - 966
(2012/04/23)
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- New nitrite ionic liquid (IL-ONO) and nanoparticles of organosilane-based nitrite ionic liquid immobilized on silica as nitrosonium sources for electrophilic aromatic nitrosation
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An improved method for the synthesis of nitrosoarenes has been developed using a new nitrite ionic liquid (IL-ONO) and immobilized nitrite ionic liquid. These ionic liquids play as nitrosonium sources for electrophilic aromatic nitrosation of active aromatics at 0-5 °C. Their action was accomplished in water and the satisfactory results were obtained under the mild conditions in short reaction time.
- Valizadeh, Hassan,Amiri, Mohammad,Shomali, Ashkan
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experimental part
p. 1103 - 1108
(2012/03/10)
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- 4-acylaminopiperidin-N-oxyle
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4-Acylaminopiperidine N-oxides Ia where A1 is hydrogen or an organic radical and B1 is a radical IIa STR1 where R1 -R4 are each C1 -C4 -alkyl and R1 and R2, on the one hand, and R3 and R4, on the other hand, may furthermore be bonded to form a 5-membered or 6-membered ring, R5 is H or C1 14 C4 -alkyl and R6 is H or C1 -C18 -alkyl, are used for stabilizing organic materials against the harmful effect of free radicals, particularly in the distillation of monomers which undergo free radical polymerization, especially styrene.
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- Process for preparing N,N-disubstituted p-phenylenediamine derivatives
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A process for preparing an N,N-disubstituted p-phenylenediamine of the formula STR1 wherein R1 is alkyl of 1-6 C atoms, R2 is alkyl of 1-6 C atoms or alkyl of 1-6 C atoms which is substituted by OH, lower alkoxy, a sulfo group or an alkylsulfonamido group and R3 is hydrogen or lower alkyl or an acid addition salt thereof, comprises adding an alkyl nitrite, as a nitrosation agent, to an aqueous, acid suspension of the corresponding aniline derivative of the formula STR2 thereby forming the corresponding N,N-disubstituted p-nitroso-aniline, and subsequently hydrogenating the latter without isolation thereof from the reaction mixture.
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