A detailed investigation was carried out of the effects of porphyrin composition on the activity and selectivity of iron(III) porphyrin catalysts used or the epoxidation of cyclooctene by hydrogen peroxide. Under conditions where the formation of -oxo-dimers can be avoided, the mechanism f cyclooctene epoxidation and hydrogen peroxide decomposition are identical for all of the porphyrin catalys...

Methylobacterium sp. strain CRL-26 grown in a fermentor contained methane monooxygenase activity in soluble fractions. Soluble methane monooxygenase catalyzed the epoxidation/hydroxylation of a variety of hydrocarbons, including terminal alkenes, internal alkenes, substituted alkenes, branched-chain alkenes, alkanes (C(1) to C(8)), substituted alkanes, branched-chain alkanes, carbon monoxide, e...

Recent clinical trials suggest that tamoxifen (TAM) is a preventive agent for breast cancer, however, the mechanism is unknown. Previously, we found that both 17beta-estradiol (E2) and estrone (E1) could be activated by epoxidation resulting in their ability to bind to DNA, forming DNA adducts both in vitro and in vivo, and to inhibit nuclear DNA-dependent RNA synthesis. Since epoxidation is re...

in this work, we report a new well dispersed molybdenum complex attached through the mediation of aminopropylsilyl groups on the surface of multi-walled carbon nanotubes (mwcnts). the prepared hybrid nanomaterial was characterized with different physicochemical methods such as fourier transform infrared and atomic absorption spectroscopies, transmission electron microscopy, energy-dispersive x-...

Photocatalytic enantioselective epoxidation of terminal olefins using a mononuclear non-heme chiral manganese catalyst, [(R,R-BQCN)MnII]2+, and water as an oxygen source yields epoxides with relatively high enantioselectivities (e.g., up to 60% enantiomeric excess). A synthetic mononuclear non-heme chiral Mn(IV)-oxo complex, [(R,R-BQCN)MnIV(O)]2+, affords similar enantioselectivities in the epo...

A retinoic acid epoxidase is present in rat kidney homogenates. It is found in the particulate fraction, and is dependent on ATP, NADPH, and oxygen. It is stimulated by Fe2+ and inhibited by Mn2+, Zn2+, Cu2+, EDTA, and N,N'-diphenyl-para-phenylenediamine. Its properties are closest to those of microsomal lipid peroxidases previously studied. Epoxidase activity is not affected by the rat's vitam...

The highly efficient asymmetric epoxidation of aldehydes by methylene transfer is now possible using new sulfonium salts.

the nanoparticles of ti-si mixed oxides (ntso) with rutile structure were prepared by sol-gel method in a mixture of alcohol and water as solvent. the solid product was characterized by xrd, ftir, sem, tem, uv, tga and laser raman spectroscopy. the catalytic activity of ntso (5-10 nm) was investigated in the epoxidation of cis stilbene, trans stilbene, and norbornene by using oxidants such as t...

Introduction PW-Amberlite is a promising catalyst for limonene epoxidation with aqueous hydrogen peroxide and acetonitrile as solvent; limonene conversion and limonene epoxide selectivity higher than 80 % and 90 %, respectively, have been reported [1,2]. The mechanistic pathway proposed for limonene epoxidation on PW-Amberlite [3], includes the interaction of H2O2 with peroxophosphotungstate sp...

Ti(IV)-salan 4 catalyzes the diastereo- and enantioselective monoepoxidation of conjugated dienes using 30% H2O2 at rt or below even in the presence of other olefins and adjacent stereocenters. Its enantiomer, ent-4, provides access to the opposite diastereomer or enantiomer. The resultant chiral allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well a...