Heteroatom oxidations nitrogen

Since dioxiranes are electrophilic oxidants, heteroatom functionalities with lone pair electrons are among the most reactive substrates towards oxidation. Among such nucleophilic heteroatom-type substrates, those that contain a nitrogen, sulfur or phosphorus atom, or a C=X functionality (where X is N or S), have been most extensively employed, mainly in view of the usefulness of the resulting oxidation products. Some less studied heteroatoms include oxygen, selenium, halogen and the metal centers in organometallic compounds. These transformations are summarized in Scheme 10. We shall present the substrate classes separately, since the heteroatom oxidation is quite substrate-dependent. 

Anodic substitution can also occur easily in the a-position to heteroatoms like nitrogen or oxygen. Thus, the indirect electrochemical oxidation of ethylene glycol dimethyl ether in methanol using tris(2,4-dibromophenyl)amine as redox catalyst leads to the formation of 2-methoxyacetaldehyde dimethylacetal [25] ... 

Cytochrome P450 enzymes not only oxidize nitrogen- or sulfur-containing substrates at the heteroatom to afford the corresponding N-oxides and (chiral)... 

It is known that aromatic compounds containing heteroatoms of nitrogen may have light stabilizing effect at polymers irradiation. Some derivates of carbazole, according to literature and patent data, may be CC and antioxidants during oxidative destruction of polymers. 

In sum, the course of heteroatom oxidation appears to be sensitive to the oxidation potential of the heteroatom, the acidity of hydrogens on the adjacent carbon, and steric factors. The bulk of the evidence suggests that oxidation of the nitrogen in amines generally involves electron abstraction followed primarily by A-dealkylation if a labile proton is present, or nitrogen oxidation if it is not. As the nitrogen oxidation potential increases, there is a shift toward direct insertion into the C-H bond, as is thought to occur in the A-dealkylation of amides. 

Animal metaboHsm is based on the reactions of oxygen and organic compounds containing carbon, hydrogen, oxygen, and nitrogen and other heteroatoms. Enzymes catalyze these biochemical oxidations, which are accompHshed at about 30—40°C and frequendy proceed stepwise to produce... 

Major unknowns in the mechanism by which a hydrocarbon fuel bums concern the pyrosynthesis reactions that lead to the formation of polycyclic aromatic hydrocarbons (PAHs) and soot and the oxidation chemistry of atoms other than carbon and hydrogen (heteroatoms) in the fuel, particularly nitrogen, sulfur, and halogens. 

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