Epoxides, hydrogenation

Pd Ketones, epoxides (hydrogen transfer from formic acid)... 

Hydrogenolysis of epoxides. Hydrogenation of the A -14a,l5a epoxide 1 over Raney nickel results in the desired alcohol 2 and the hydroxyl-free olefin 3 in about... 

Metal-Catalyzed Epoxidation. Hydrogen peroxide is able to convert alkenes to epoxides in the presence of metal catalysts. Several metal oxides (Mo03, W03, Se02, V205) are known to catalyze such epoxidations.2,245,278,279 All these catalysts form stable inorganic peracids, and these peracids are supposedly involved in epoxidation in a process similar to organic peracids. 

A considerable amount of work haa been devoted to the catalytic reduction of fatty acid and fatty alcohol epoxides. Hydrogenation of is- and tran -Q, 1 tl-epoxyooUtbcanoic add, for example, has been reported108t-1887 1188 to give isomeric 10-hydroxyoctadecanoio acids exclusively (Eq. 344). Preferential attack of hydrogen on C< was... 

Azidonitration Deoxygenation Dihydroxylation Epoxidation Hydrogenation Oxidation Photobromination Reduction... 

Key Words Lewis acid adducts, Radical oxidations, Epoxidation, Hydrogen peroxide, Bond dissociation energy, Catalyst durability, Methyltrioxorhenium, Cross-bridged cyclam, Mn(IV), Late transition metal. Propylene oxide. Titanium silicalite (TS-1) catalyst, Ethylanthrahydroquinone/H2 process, Polyoxometallates, Mn(IV) catalyst. Hydrogen abstraction. Rebound mechanism, Isotopic label, t-BuOOH, Peroxide adduct. 2008 Elsevier B.v. 

Key Words Carbonic anhydrase, Enantioselective epoxidation. Hydrogen peroxide. 

Variants of TUD-1 have been shown to be effective for a wide range of reactions, some of which include alkylation, cracking, epoxidation, hydrogenation, hydrogenolysis, etc. One exciting area is the use of zeolites embedded in TUD-1 to give a synergistic performance for various probe reactions. 

Anarcadic acid derivatives (in particular cardanol) and umshiols were transformed in several typical metal-catalyzed transformations (epoxidation, hydrogenation, and metathesis) [19] however, to date, hydroformylation has not been investigated, although a potential as plasticizers for PVC has been proven [20]. 

Oxirans.—All the stereoisomeric methyl 2,3-anhydro-6-deoxy-DL-hexopyranosides or their 4-O-acetyl derivatives or both have been prepared by epoxidation (hydrogen peroxide-benzonitrile) of methyl 2,3,6-trideoxy-oL-hex-2-enopyrano-sides or their 4-acetates. ... 

Keywords Epoxide Hydrogenation Multi-step functionalization Oxidatimi Polybutadiene Polymer-analogous reactions Post-modification Subsequent... 

The reactivity of the epoxides towards certain nucleophiles, and optionally in combination with electrophilic catalysis [173], is also used to characterize epoxidized PBDs. The epoxide content in PBDs is usually determined by titration methods using acids that add to epoxides. Hydrogen bromide [174], perchloric acid [175], and hydrochloric acid [166,176] are typical examples they can expand the accuracy of measurement in combination with spectroscopic techniques [177]. The polymeric products are hydrins. 

This chapter will cover recent developments in the production, use and characterization of fatty acids and their derivatives as surface-active materials. However, the chapter will be limited to surfactants where the original, native, fatty acid plays an evident role in the properties of the surfactant and will not include the many surfactant classes in which the hydrocarbon backbone or carboxylic group have been modified (e.g. by epoxidation, hydrogenation, amidation) or where the surfactant properties are mostly decided by the variations in the polar head group (e.g. carbohydrate derivatives, amino acids). 

The hydrogenolyaia of cyclopropane rings (C—C bond cleavage) has been described on p, 105. In syntheses of complex molecules reductive cleavage of alcohols, epoxides, and enol ethers of 5-keto esters are the most important examples, and some selectivity rules will be given. Primary alcohols are converted into tosylates much faster than secondary alcohols. The tosylate group is substituted by hydrogen upon treatment with LiAlH (W. Zorbach, 1961). Epoxides are also easily opened by LiAlH. The hydride ion attacks the less hindered carbon atom of the epoxide (H.B. Henhest, 1956). The reduction of sterically hindered enol ethers of 9-keto esters with lithium in ammonia leads to the a,/S-unsaturated ester and subsequently to the saturated ester in reasonable yields (R.M. Coates, 1970). Tributyltin hydride reduces halides to hydrocarbons stereoselectively in a free-radical chain reaction (L.W. Menapace, 1964) and reacts only slowly with C 0 and C—C double bonds (W.T. Brady, 1970 H.G. Kuivila, 1968). 

Several cortisone derivatives with glucocorticoid effects are most active, if they contain fluorine in the 9or-position together with an Il(9-OH group. Both substituents are introduced by the cleavage of a 9,11 -epoxide with hydrogen fluoride. The regio- and stereoselective formation of the -epoxide is achieved by bromohydrination of a 9,11-double bond and subsequent alkali treatment (J. Fried, 1954). 

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