29770-78-3Relevant academic research and scientific papers
A molybdenum-catalyzed oxidative system forming oxazines (hetero-Diels-Alder adducts) from primary aromatic amines, hydrogen peroxide, and conjugated dienes
Moller, Eval Rud,Jorgensen, Karl Anker
, p. 5770 - 5778 (1996)
The development of a new molybdenum-catalyzed procedure for the formation of oxazines-hetero-Diels-Alder adducts - from primary aromatic amines, hydrogen peroxide, and conjugated dienes is presented. The method is based on a molybdenum-peroxo complex, which in the presence of hydrogen peroxide as the terminal oxidant selectively catalyzes the oxidation of primary aromatic amines to the corresponding dienophilic nitroso compounds. The molybdenum-peroxo catalyst is under the present reaction conditions not reactive toward conjugated dienes and substituents attached to the aromatic nuclei of the primary aromatic amines. Several oxazines are synthezised following this new procedure using primary aromatic amines having either electron-withdrawing or electron-donating substituents and 1,3-cyclohexadiene as the standard diene. The scope of the new procedure is also demonstrated by the preparation of several oxazines using different alkyland phenyl-substituted conjugated dienes and 4-chloroaniline as precursor for the dienophile. Moderate diastereomeric excesses are found when the reaction is carried out with 1-(2-aminophenyl)-ethanol and 1,3-cyclohexadiene or (E)-1-phenyl-1,3-butadiene. The stereochemical and electronic factors governing the reaction course are briefly discussed.
Titania-Supported Gold Nanoparticles Catalyze the Selective Oxidation of Amines into Nitroso Compounds in the Presence of Hydrogen Peroxide
Fountoulaki, Stella,Gkizis, Petros L.,Symeonidis, Theodoros S.,Kaminioti, Eleni,Karina, Athanasia,Tamiolakis, Ioannis,Armatas, Gerasimos S.,Lykakis, Ioannis N.
, p. 1500 - 1508 (2016/05/19)
In this article, the catalytic activity of titania-supported gold nanoparticles (Au/TiO2) was studied for the selective oxidation of amines into nitroso compounds using hydrogen peroxide (H2O2). Gold nanoparticles deposited on Degussa P25 polymorphs of titania (TiO2) have been found to promote the selective formation of a variety of nitroso arenes in high yields and selectivities, even in a large-scale synthesis. In contrast, alkyl amines are oxidized to the corresponding oximes under the examined conditions. Kinetic studies indicated that aryl amines substituted with electron-donating groups are oxidized faster than the corresponding amines bearing an electron-withdrawing functionality. A Hammett-type kinetic analysis of a range of para-X-substituted aryl amines implicates an electron transfer (ET) mechanism (ρ=-1.15) for oxidation reactions with concomitant formation of the corresponding N-aryl hydroxylamine as possible intermediate. We also show that the oxidation protocol of aryl amines in the presence of 1,3-cyclohexadiene leads in excellent yields to the corresponding hetero Diels-Alder adducts between the diene and the in situ formed nitrosoarenes.
In situ generation of nitroso compounds from catalytic hydrogen peroxide oxidation of primary aromatic amines and their one-pot use in hetero-Diels-Alder reactions
Zhao, Dongbo,Johansson, Mikael,Baeckvall, Jan-E.
, p. 4431 - 4436 (2008/04/13)
A method for in situ generation of nitroso compounds from organoselenium-catalyzed oxidation of anilines by hydrogen peroxide was developed. The generated nitroso compounds were subsequently used in hetero-Diels-Alder reactions. A variety of oxazines were synthesized in reasonable to good yields by this one-pot procedure using primary aromatic amines with different substituents and various conjugated dienes. This strategy might facilitate the current methodologies for nitroso chemistry since no isolation or purification of the nitroso compounds is required. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
