Peroxides hydro

Rotation barriers for Cd—CH3 bonds for all peroxides (hydro and methyl-peroxides) have the same 3-fold symmetry and have all relatively low barriers, 1.3 to 2.1 kcal mof ... 

Catalase (-L-arginine) hydrolase Hydrogen-peroxide hydro- 1.11.1.6 103... 

Again, as with pyridopyrimidines, the main reaction is oxidation of di- or poly-hydro derivatives to fully aromatic structures, often merely by air or oxygen. In some cases the reagent of choice is mercury(II) oxide, whilst other reagents used include sulfur, bromine, chloranil, chromium trioxide-acetic acid, hydrogen peroxide, and potassium ferricyanide, which also caused oxidative removal of a benzyl group in the transformation (306) (307)... 

A useful oxidizing reagent is silver(III) tristrifluoroacetate which can be generated from silver peroxide (AgO) and a tnfluoroacetic acid-tnfluoroacetic anhydride mixture [5f] This reagent readily oxidizes alicyclic and bicyclic hydro... 

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). 

Hydro-peroxyd, n. hydrogen peroxide, -per-sulfid, n. hydrogen persulfide, hydro-phil, n. hydrophile, hydrophil(ie). -phob, a. hydrophobe, hydrophobie. 

The mononuclear peroxide complexes can further be divided into three subgroups peroxy-complexes, perhydrocomplexes, and hydro per-... 

In 1993, Linford firstly reported a quite useful method to prepare monolayers of alkyl chains by thermal hydros-ilylation of hydrogen-terminated silicon surfaces [25]. Alkyl chains are covalently bound to Si surface by Si-C bonds. This thermal hydrosilylation could be attributed to a free-radical process with 1-alkene. First, a diacyl peroxide initiator was used to produce free radicals. However, at higher temperature, only hydrogen-terminated silicon and a neat solution of 1-alkene or 1-alkyne can form Si-C linkages [26]. Furthermore, lately it is found that such Si-C covalent links can be observed even in dilute solutions of 1-alkenes [27]. In that case, the density of monolayer packing strongly depends on the reaction temperature. 

Cohen, G. and Hochstein, P. (1963). Glutathione peroxidase the primary agent for the elimination of hydro n peroxide in erythrocytes. Biochemistry 2, 1420-1428. 

Further investigations for the radical isomerisation of hydro-spirophosphoranes have shown that, on heating with di-t-butyl peroxide in benzene, phosphoranes (66) and (67) are transformed into (68) and (69) respectively93. The proposed mechanism, as written for (67), proceeds through the phosphoranyl radical (70) which rearranges to (71) which in turn reacts with (67) to form (69) and (70) in the propagation step. 

We developed a convenient synthesis of 3-cyclopentenyl hydroperoxide via hydro-boration and autoxidation of cyclopentadiene, and bromination proceeded smoothly to afford 32 40). Ring closure with silver trifluoroacetate (Eq. 26) afforded a 5-bromo-2,3-dioxabicyclo[2.2.1]heptane 34 (6%) and a 5-trifluoroacetoxy-2,3-dioxabicyclo-[2.2.1]heptane 35 (14%), and it was shown independently that 34 is rapidly converted into 35 by reaction with Ag02CCF3. To avoid the trifluoroacetate bromide substitution that accompanies and competes with the dioxabicyclization, 32 was treated with silver oxide and this slowly yielded an isomeric 5-bromo-peroxide 33 (42 %) (Eq. 26). 

The stoichiometry and kinetics of gas phase epoxidation of cyclohexene by silica-supported Ti(0 Pr)4 upon treatment with /< r/-butyl hydro peroxide were the... 

The substituted hydroxylamine C NOPP from reaction 7) can take part in various dark reactions, even at ambient temperature. From a study of the low molecular weight model I in the liquid phase, two decomposition pathways are possible (reaction 8) (12). The products from the disproportionation reaction 8a were only observed in the absence of a radical trap such as O2. In a given solvent ks kaa-Uo (solvent air saturated and degassed respectively). Both k8a and ke were found to increase by an order of magnitude on going from a non-polar solvent (iso-octane) to a polar solvent (methanol or tert.-butyl hydro peroxide, BuOOH). 

C. 3,5-Dibromosulfanilamide. The bromination of sulfanilamide is carried out in much the same way as the chlorination. The stirrer must be more efficient (Note 9) a glass stirrer with two sets of blades is satisfactory if run at high speed. Fifty grams (0.29 mole) of sulfanilamide is dissolved in a mixture of 850 ml. of water (Note 9) and 100 ml. (0.68 mole) of 40% hydro-bromic acid (Note 10). The solution is heated as above, but to 70-75°, and 65 g. (59 ml., 0.58 mole) of 30% hydrogen peroxide is added (Notes 2 and 11). A precipitate settles in 2 to 3 minutes, and the solution becomes yellow. The heat of reaction causes the internal temperature to rise without further application of heat to a maximum of 85-90° after 10 minutes by the end of the reaction time the temperature will have fallen to about... 

Hock Also known as the Hock Lang process, and the cumene peroxidation process. A process for converting isopropyl benzene (cumene) to a mixture of phenol and acetone m-di-isopropyl benzene likewise yields resorcinol, and p-di-isopropyl benzene yields hydro-quinone. The basis of the process is the liquid-phase air oxidation of cumene to cumene hydroperoxide ... 

Soak in fresh "piranha" soluhon (concentrated sulfuric acid hydro-gen peroxide, 2 1 v/v). 

Alkyl hydroperoxides react with Af,Af-bis(trunethylsilyl)acetamide to give alkyl hydro-peroxysilanes. For example, 3-hydroperoxycyclopentene, -cyclohexene and -cyclooctene react with Af,Af-bis(trimethylsilyl)acetamide in a 2 1 mole ratio to yield the corresponding trimethylsilyl cycloalkenyl peroxide 17 (equation 27). ... 

The preparation of acyclic allylic hydroperoxides has been described before (3, 7, 9), but it is not clear how the reactivities differ from the better known saturated hydroperoxides and cyclic allylic hydroperoxides. Dykstra and Mosher prepared allyl hydroperoxide by the reaction of allyl methanesulfonate with hydrogen peroxide and alcpholic potassium hydroxide and purified the hydroperoxide by gas chromatography. It detonated on heating and decomposed on exposure to light but was relatively stable in the cold and dark. The isomeric allylic hydroperoxides formed from the autoxidation of the branched olefin, 4-methyl-2-pentene, have also been isolated and were not abnormally reactive (3). In the present study, cis- and trans-2-butene were photooxidized in the presence of methylene blue as a sensitizer (14), and the product, l-butene-3-hydro-peroxide, was isolated by preparative chromatography. 1-Butene proved unreactive and 2-butene-l-hydroperoxide could be formed only by isomerization of the secondary hydroperoxide. 

CH, 1 [ jj CHj (Uberschuss) Dibenzoyl-peroxid/ Cumen, 0° 5,12-Dimethyl-5,6,ll,12-tetra-hydro-(dibenzo[6 e]-l,5-diazociri 70c 3... 

The volatiles produced by the LOX pathway and autoxidation are typically volatile aldehydes and alcohols responsible for fresh and green sensorial notes. In the LOX pathway these volatile compounds are produced in response to stress, during ripening or after damage of the plant tissue. The pathway is illustrated in Scheme 7.2. Precursors of the LOX (EC 1.13.11.12) catalysed reactions are Cis-polyunsaturated fatty acids with a (Z,Z)-l,4-pentadiene moiety such as linoleic and a-linolenic acids that are typically oxidised into 9-, 10- or 13-hydro-peroxides depending on the specificity of the LOX catalyst. These compounds are then cleaved by hydroperoxide lyase (HPL) into mainly C, C9 and Cio aldehydes, which can then be reduced into the corresponding alcohols by alcohol dehydrogenase (ADH EC 1.1.1.1) (Scheme 7.2) [21, 22]. The production of volatile compounds by the LOX pathway depends, however, on the plants as they have different sets of enzymes, pH in the cells, fatty acid composition of cell walls, etc. 

Mach investigated hydrogen peroxide oxidation of 2.4.6-tri-tert-butyl-X -phos-phorin 24 in analogy to pyridine oxidation to pyridine-N-oxide. Whereas 2.4.6-tri-tert-butyl-pyridine could be recovered unchanged, 2.4.6-tri-tert-butyl-X -phos-phorin under the same conditions is irranediately oxidized to the 2-hydro-phos-phinic acid m.p. 203 °C (transformation at 170 °C) 86 (CH3 = H) which, accord-... 

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