Hydrogen oxidation with

Pure iron is prepared by reduction of iron(II) oxide with hydrogen, or by electrolysis of an iron(II)-containing aqueous solution. It is a fairly soft metal, existing in different form according to temperature ... 

The formation of trisubstituted A-4 thiazoline-2-ones from the corresponding thiones analogs can be performed by oxidation with hydrogen peroxide under basic conditions. This reaction is strongly dependent on the pH of the medium. Higher yields are obtained in strongly alkaline solution (883). 

Little work has been carried out on thiazole N-oxides. These products are unstable and breakdown by autoxidation to give thiazolium-A -oxide sulfates and other decomposition products (264). They are prepared by direct oxidation with hydrogen peroxide, or by tungstic acid (264, 265) or peracetic acid (265-267). 

Oxidation of 4 ten butylthiane (see Problem 16 23 for the structure of thiane) with sodium metaperiodate gives a mixture of two compounds of molecular formula CpHigOS Both products give the same sulfone on further oxidation with hydrogen peroxide What is the relationship between the two compounds ... 

Reduction of metal oxides with hydrogen is of interest in the metals refining industry (94,95) (see Metallurgy). Hydrogen is also used to reduce sulfites to sulfides in one step in the removal of SO2 pollutants (see Airpollution) (96). Hydrogen reacts directiy with SO2 under catalytic conditions to produce elemental sulfur and H2S (97—98). Under certain conditions, hydrogen reacts with nitric oxide, an atmospheric poUutant and contributor to photochemical smog, to produce N2 ... 

Oxidation. Ketones are oxidized with powerful oxidizing agents such as chromic or nitric acid. During oxidation, carbon—carbon bond cleavage occurs to produce carboxyHc acids. Ketone oxidation with hydrogen peroxide, or prolonged exposure to air and heat, can produce peroxides. Concentrated solutions of ketone peroxides (>30%) may explode, but dilute solutions are useful in curing unsaturated polyester resin mixtures (see... 

G. Stmkul, ki G. Stmkul, ed.. Catalytic Oxidations with Hydrogen Peroxide as Oxidant, Kluwer Academic Pubhshers, Dordrecht, 1993, Chapt. 6. 

Nitroxyl radicals of diarylamines can also be obtained on oxidation with hydrogen peroxide in the presence of vanadium ions. Resonance helps stabili2e these radicals. Eor example, the nitroxide from 4,4 -dimethoxydiphenylainine [63619-50-1] is stable for years, whereas the radical from the unsubstituted diphenylamine caimot be isolated. Substitution in the ortho and para positions also increases the stabiUties of these nitroxides by inhibiting coupling reactions at these sites. However, they are not as stable as the stericaHy hindered tetramethylpiperidyl radical. 

Ethylene Cyanohydrin. This cyanohydrin, also known as hydracrylonitnle or glycocyanohydrin [109-78-4] is a straw-colored Hquid miscible with water, acetone, methyl ethyl ketone, and ethanol, and is insoluble in benzene, carbon disulfide, and carbon tetrachloride. Ethylene cyanohydrin differs from the other cyanohydrins discussed here in that it is a P-cyanohydrin. It is formed by the reaction of ethylene oxide with hydrogen cyanide. 

Hydrogen peroxide can also be activated by ultraviolet radiation or o2one and ultraviolet radiation (178,188,189). One of the most active fields in waste treatment is ultraviolet-cataly2ed oxidation with hydrogen peroxide (190—194). The uv light activates the hydrogen peroxide converting it to hydroxyl radicals (195). 

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

Pyrogallol monomethyl ether has been prepared by the methylation of pyrogallol with dimethyl sulfate or methyl iodide by the decarboxylation of 2,3-dihj droxy-4-methoxy-benzoic acid and by the methylation of pyrogallol carbonate with diazomethane and subsequent hydrolysis. The method described is taken from the improved procedure of Baker and Savage for the preparation of pyrogallol monomethyl ether from o-vanillin by oxidation with hydrogen peroxide. 

Constitution. When coniine is distilled with zinc dust or heated with silver acetate/ a new base, coiiyrine, CgH N, differing from coniine by six atoms of hydrogen, is formed. This on oxidation yields pyridine-2-carboxylic acid and, since it is not identical with 2-isopropylpyridine, must be 2-propylpyridine (I). When coniine is heated with hydriodic acid at 300° it yields w-octane (II). These and other observations due mainly to A. W. Hofmann, made it clear by 1885 that coniine was probably a-propylpiperidine (III), and this has been amply confirmed by other reactions of the alkaloid and by syntheses. Thus, Wolffenstein showed that on oxidation with hydrogen peroxide, coniine is converted into amino-w-propylvaleraldehyde (IV) ... 

The former passes into the second on further oxidation with hydrogen peroxide, indicating that it is an a-keto-carboxylic acid. Acid (b) loses carbon dioxide on fusion and gives a neutral substance, CjaHj OgN, m.p. 238°, which was shown to be 6 7-methylenedioxy-A-methylphenanthri-done (I), by comparison with a synthetic specimen. The position of the carboxyl group in (b) could not be determined by synthetic methods but is probably at since dihydrolycorineanhydromethine, Cl 7 7 2 ) m.p. 87-5° [picrate, m.p. 174° (dec.) methiodide, m.p. 236° (dec.)] on distillation with zinc dust yields a mixture of phenanthridine, 1-methyl-phenanthridine and 6 7-methylenedioxyphenanthridine, m.p. 142° [picrate, m.p. 257° (dec.)], the identity of the two latter being established by comparison with the synthetic products. These results indicate for lycorineanhydromethine formula (II). 

Difluoroalkenyl boranes, which are prepared in situ, are converted to difluoromethyl ketones by oxidation with hydrogen peroxide m alkaline media [720] (equation 107)... 

The stereochemical course of reduction of imonium salts by Grignard reagents was found to depend on the structure of the reagent 714). Hydro-boration of enamines and oxidation with hydrogen peroxide led to amino-alcohols (7/5). While aluminum hydrogen dichloride reacted with enamines to yield mostly saturated amines and some olefins on hydrolysis, aluminum hydride gave predominantly the unsaturated products 716). 

In an attempt to protect thiophenols during electrophilic substitution reactions on the aromatic ring, the three substituted thioethers were prepared. After acetylation of the aromatic ring (with moderate yields), the protective group was converted to the disulfide in moderate yields, 50-60%, by oxidation with hydrogen peroxide/boiling mineral acid, nitric acid, or acidic potassium permanganate. ... 

In addition to having typical A -oxide reactions, quinazoline 3-oxide also shows the same reactivity as quinazoline toward nucleophilic reagents, but the reaction goes a step further by eliminating water as shown in reaction 2d. Oxidation with hydrogen peroxide... 

Oxidations of pyridopyrimidines are rare, but the covalent hydrates of the parent compounds undergo oxidation with hydrogen peroxide to yield the corresponding pyridopyrimidin-4(3 T)-ones. Dehydrogenation of dihydropyrido[2,3-(i]pyrimidines by means of palladized charcoal, rhodium on alumina, or 2,3-diehloro-5,6-dicyano-p-benzo-quinone (DDQ) to yield the aromatic derivatives have been reported. Thus, 7-amino-5,6-dihydro-1,3-diethylpyrido[2,3-d]-pyri-midine-2,4(lif,3f/)-dione (177) is aromatized (178) when treated with palladized charcoal in refluxing toluene for 24 hours. 

Oxidation of 4-methylquinoxalin-3-one 2-carboxy-fV -methylamlide (45) with hydrogen peroxide and acetic acid furnishes the 1-oxide but, on removal of either or both of the fV-raethyl groups (giving 46, 47, or 48), oxidation with hydrogen peroxide or with peracetic or perbenzoic acid results in the removal of the carboxyamide groups and the formation of a quinoxaline-2,3-dione. ... 

A heterocyclic ring may be used in place of one of the benzene rings without loss of biologic activity. The first step in the synthesis of such an agent starts by Friedel-Crafts-like acylation rather than displacement. Thus, reaction of sulfenyl chloride, 222, with 2-aminothiazole (223) in the presence of acetic anhydride affords the sulfide, 224. The amine is then protected as the amide (225). Oxidation with hydrogen peroxide leads to the corresponding sulfone (226) hydrolysis followed by reduction of the nitro group then affords thiazosulfone (227). ... 

Benzocyclobutene-l,2-dione (11) can be condensed with benzene-1.2-diamine to provide an annulated quinoxaline (cf. Houben-Weyl, Vol. E9b/Part 2, p203), which on oxidation with hydrogen peroxide in acetic acid leads to the 1,4-diazocine derivative 12.34... 

ALLYLIC OXIDATION WITH HYDROGEN PEROXIDE-SELENIUM DIOXIDE frans-PINOCARVEOL... 

Chemical Reactions. It is readily oxidized with hydrogen peroxide to the nitro compd (Ref 4). 

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