S-Oxide reactions

Cytochrome P-450 Catalyzed Reactions - Studies with 02 have established that the cytochrome P-450 mediated hydroxylation of camphor by the bacterial enzyme and the enzyme purified from rat liver results in the incorporation of atmospheric oxygen in the 5-exo-hydroxylation product. Cumene [ 02]hydroperoxide will transfer its peripheral oxygen atom to a variety of compounds which serve as substrates for mammalian cytochrome P-450. As expected, 02 served as the oxygen source for the bacterial cytochrome P-450 catalyzed epoxidation of 5,6-dehydrocamphor.N-Hydroxy-methylcarbazole, formed by the cytochrome P-450 catalyzed oxidation of N-raethylcarbazole, incorporates 0 exclusively from dioxygen. Under anaerobic conditions cytochrome P-450 may catalyze the intramolecular transfer of oxygen present in tertiary amine N-oxides. Mechanistic studies on S-dealkylation and S-oxidation reactions also have used tracer methods. ... 

Thiophosgene S-oxide, reactions with - 26, 697 Thiophosphinic... s. Bis(thio-phosphinyl)..., Dithio-phosphinic... Thiophosphonic... s. 

Other aging mechanisms trigger a change in the crystalline stmcture of the positive electrode s active material at the interface with the electrolyte. The active material, particularly in the case of a layered oxide, can serve as a source of oxygen for the electrolyte s oxidation reactions. A layer then forms at the extreme surface of the active material, made up of a rock salt phase deficient in lithium and oxygen (Figure 2.10). 

The introduction of additional alkyl groups mostly involves the formation of a bond between a carbanion and a carbon attached to a suitable leaving group. S,.,2-reactions prevail, although radical mechanisms are also possible, especially if organometallic compounds are involved. Since many carbanions and radicals are easily oxidized by oxygen, working under inert gas is advised, until it has been shown for each specific reaction that air has no harmful effect on yields. 

Thiazole carboxylic acid hydrazides were prepared in a similar way (444, 445). Thus by refluxing thioacetamide or thiobenzamide with y-bromoaceto acetic ester arylhydrazones (83) for several hours in alcohol the 4-carboxythiazole derivatives (84) listed in Table II-ll were obtained (Scheme 36) (656). This reaction is presumed to proceed via dehydration of the intermediate, thiazoline-S-oxide. 

Before the equivalence point the titration mixture consists of appreciable quantities of both the oxidized and reduced forms of the analyte, but very little unreacted titrant. The potential, therefore, is best calculated using the Nernst equation for the analyte s half-reaction... 

Although EXo /ATcd is standard-state potential for the analyte s half-reaction, a matrix-dependent formal potential is used in its place. After the equivalence point, the potential is easiest to calculate using the Nernst equation for the titrant s half-reaction, since significant quantities of its oxidized and reduced forms are present. 

Coupling the mediator s oxidation or reduction to an acid-base, precipitation, or complexation reaction involving the analyte allows for the coulometric titration of analytes that are not easily oxidized or reduced. For example, when using H2O as a mediator, oxidation at the anode produces H3O+... 

Sign Conventions Since the reaction of interest occurs at the working electrode, the classification of current is based on this reaction. A current due to the analyte s reduction is called a cathodic current and, by convention, is considered positive. Anodic currents are due to oxidation reactions and carry a negative value. 

The chemical properties of cycHc ketones also vary with ring size. Lower members (addition reactions, than corresponding acycHc ketones. The Cg—C 2 ketones are unreactive, reflecting the strain and high enol content of medium-sized ring systems. Lactones are prepared from cycHc ketones by the Bayer-ViUiger oxidation reaction with peracids. S-Caprolactone is manufactured from cyclohexane by this process ... 

Oxidation. Aromatic amines can undergo a variety of oxidation reactions, depending on the oxidizing agent and the reaction conditions. For example, oxidation of aniline can lead to formation of phenyUiydroxylamine, nitrosobenzene, nitrobenzene, azobenzene, azoxybenzene or -benzoquinone. Oxidation was of great importance in the early stages of the development of aniline and the manufacture of synthetic dyes, such as aniline black and Perkin s mauve. 

Basic Red 22 (134), which contains 1 part ia 7 of the yellowish red 1,4-dimethyl isomer, Basic Red 29 (135), and Basic Yellow 25 (136) are all examples of delocalized cationic azo dyes. Dyes of this type can also be synthesized by Hbnig s oxidative coupling reaction of heteroaromatic hydrazones with tertiary aromatic amines. 

Imidazole, 1 -hydroxy-2,4,5-triphenyl-3-oxides reactions, S, 455 Imidazole, iodo-nitrodehalogenation, 5, 396-397 Imidazole, 1-iodo-reactions, S, 454 stability, S, 110 Imidazole, 2-iodo-synthesis, S, 401 Imidazole, N-iodo-, S, 393 reactions, 5, 454 Imidazole, 4-iodo-5-methyl-iodination, 5, 400 Imidazole, 2-isopropyl-4-nitro-N-nitration, 5, 351 Imidazole, 2-lithio-reactions, S, 106, 448 Imidazole, 2-mercapto-l-methyl-as antithyroid drug, 1, 171 mass spectra, 5, 358 Imidazole, 1-methoxymethyl-acylation, S, 402 Imidazole, 5-methoxy-l-methyl-reactions... 

S-group removal from, S, 445 oxidation, S, 445 reactions, S, 443-445 reactivity, 5, 375-376 synthesis, S, 493 Imidazoline-2-thiones Mannich reaction, 5, 405 reactions, 5, 102, 443-444 with alkynes, 5, 444 synthesis, S, 493... 

Isoxazole, 3-acetyl-4-chloro-5-methyl-oxidation, 6, 27, 53 Isoxazole, 3-acetyl-4,5-dimethyl-oxidation, 6, 27, 53 Isoxazole, 5-acetyl-3-methoxy-reactions, 6, 53 Isoxazole, 3-acyl-furazans from, 6, 417 nucleophilic attack, S, 93 reactions with bases, 6, 30... 

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