نتایج جستجو برای: αβ unsaturated compounds

تعداد نتایج: 242522  

Journal: :Organic & biomolecular chemistry 2011
José A Manso Isaac F Céspedes Camacho Emilio Calle Julio Casado

Alkylation reactions of the nucleoside guanosine (Guo) by the α,β-unsaturated compounds (α,β-UC) acrylonitrile (AN), acrylamide (AM), acrylic acid (AA) and acrolein (AC), which can act as alkylating agents of DNA, were investigated kinetically. The following conclusions were drawn: i) The Guo alkylation mechanism by AC is different from those brought about the other α,β-UC; ii) for the first th...

Journal: :journal of chemical health risks 0
alireza motavalizadehkakhky department of chemistry, neyshabur branch, islamic azad university, neyshabur, iran ali shafaghat department of chemistry, pharmaceutical sciences branch, islamic azad university, tehran, iran jamshid mehrzad department of chemistry, neyshabur branch, islamic azad university, neyshabur, iran masoud shafaghatlonbar department of chemistry, tehran north branch, islamic azad university, tehran, iran farzaneh azimi agriculture research center, ardabil, iran zohreh ebrahimi department of chemistry, neyshabur branch, islamic azad university, neyshabur, iran

in this study, both the presence and concentration of some unsaturated compounds in hexane extracts of different parts of anthemis talyschensis showing absorption at wavelength 280-450 nm were surveyed, with the view of possibly using extracts of this plant in new formulations of sunscreen creams. the hexane extracts of flower, leaf and stem of a. talyschensis , collected from northwest iran, w...

Journal: :The Journal of biological chemistry 1955
A L TAPPEL

Hematin catalysis of unsaturated lipide oxidation is probably a primary reaction in many types of pathological unsaturated fat oxidation in viva (l-3) and in the spoilage of frozen meat products by oxidative fat rancidity (4). Some of the properties of hematin catalysis have been described (4-8), but knowledge of the reaction mechanism and the reaction products is relatively meager. The catalyt...

Journal: :Electr. J. Comb. 2008
Xiang-dong Hou

Let Q2m be the generalized quaternion group of order 2 m and DN the dihedral group of order 2N . We classify the orbits in Q2m and D n pm (p prime) under the Hurwitz action. 1 The Hurwitz Action Let G be a group. For a, b ∈ G, let a = bab and a = bab. The Hurwitz action on G (n ≥ 2) is an action of the n-string braid group Bn on G . Recall that Bn is given by the presentation Bn = 〈σ1, . . . , ...

Journal: :Angewandte Chemie 2013
Junming Mo Liang Shen Yonggui Robin Chi

Saturated carbonyl compounds, such as aldehydes and esters, are basic building blocks for the synthesis of organic molecules and materials. Reactions with carbonyl compounds as substrates primarily occur at the carbonyl carbon atom (as an electrophilic center) or the a-carbon atom (as a prenucleophile). In organocatalysis, several powerful approaches have been developed for the asymmetric funct...

2015
Patricia. M. Medeiros Michael Seidel Leanne C. Powers Thorsten Dittmar Dennis A. Hansell William L. Miller

The composition and photochemical transformations of dissolved organic matter (DOM) in the northern North Pacific Ocean were investigated at the molecular level using ultrahigh resolution mass spectrometry and geochemical tracers. Analyses included vertical profiles and experiments in which deep sea DOM was exposed to sunlight and incubated in the dark. The composition of the deep sea DOM was f...

Journal: :Molecules 2010
Antoni Riera María Moreno

An overview of the synthesis and applications of chiral 2,3-epoxy alcohols containing unsaturated chains is presented. One of the fundamental synthetic routes to these compounds is Sharpless asymmetric epoxidation, which is reliable, highly chemoselective and enables easy prediction of the product enantioselectivity. Thus, unsaturated epoxy alcohols are readily obtained by selective oxidation o...

2004
Ursula Biermann Jürgen O. Metzger

A large number of novel fatty compounds have been synthesized by catalytic C,C-bond forming addition reactions to the C,Cdouble bond of unsaturated fatty compounds. Radical reactions such as the solvent-free addition of -halocarboxylic acid esters initiated by electron transfer, e.g., from copper to give fat-derived -lactones are described as well as Lewis acid–induced electrophilic addition re...

Bahman Tamami Moredin Goudarzian

The difficult to handle and store zinc borohydride, Zn(BH4)2, is stabilized by supporting it on polyvinylpyridine. This new mild, efficient, selective, and regenerable polymer supported borohydride reducing agent reduces a variety organic compounds such as, aldehydes, a-b-unsaturated carbonyl compounds, acid chlorides, epoxides, disu...

Journal: :Physical chemistry chemical physics : PCCP 2015
Yongjie Xi Zhangxian Chen Vincent Gan Wei Kiat Liang Huang Hansong Cheng

Hydrogenation of unsaturated organosulfur compounds is an essential process through which these species are converted into cleaner and more useful compounds. Hydrogen bronze materials have been demonstrated to be efficient catalysts in hydrogenation of simple unsaturated compounds. Herein, we performed density functional theory calculations to investigate hydrogenation of thiophene on hydrogen ...

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