نتایج جستجو برای: stereoelectronic effects
تعداد نتایج: 1544327 فیلتر نتایج به سال:
Organophosphorus (OP) nerve agents that inhibit acetylcholinesterase (AChE; EC 3.1.1.7) function in the nervous system, causing acute intoxication. If untreated, death can result. Inhibited AChE can be reactivated by oximes, antidotes for OP exposure. However, OP intoxication caused by the nerve agent tabun (GA) is particularly resistant to oximes, which poorly reactivate GA-inhibited AChE. In ...
A recombinant ketoreductase from Pichia glucozyma (KRED1-Pglu) was used for the enantioselective reduction of various mono-substituted acetophenones. Reaction rates of meta- and para-derivatives were consistent with the electronic effects described by σ-Hammett coefficients; on the other hand, enantioselectivity was determined by an opposite orientation of the substrate in the binding pocket. R...
We have investigated the oxidative behaviour of natural compounds such as methyl abietate (1), farnesyl acetate (2), α-ionone (3), β-ionone (4), methyl linolelaidate (5), methyl linolenate (6) and bergamottin (7) with the oxidant system methyltrioxo-rhenium/ H2O2/pyridine. The reactions, performed in CH2Cl2/H2O at 25 °C, have shown good regio- and stereoselectivity. The oxidation products were ...
SYNTHESIS OF OLIGOSACCHARIDE MIMETICS BY THE DESULFURATIVEREARRANGEMENT OF ALLYLIC DISULFIDES AND STEREOELECTRONICINFLUENCE OF C-O BONDS ON CAND O-GLYCOSYLATIONbyMYRIAME MOUME-PYMBOCKMay 2013Advisor:Dr David CrichMajor:ChemistryDegree:Doctor of PhilosophyThis dissertation focuses on two different problems. The first part of thismanuscript ...
The unusual stability of bis- and tris-peroxides contradicts the conventional wisdom - some of them can melt without decomposition at temperatures exceeding 100 °C. In this work, we disclose a stabilizing stereoelectronic effect that two peroxide groups can exert on each other. This stabilization originates from strong anomeric nO → σ*CO interactions that are absent in mono-peroxides but reintr...
Stereoelectronic effects is a bridge between structure and reactivity [1]. Anomeric effect plays an important role in the domain of stereoelectronic interaction and can be used for description of several unusual phenomena. Intramolecular negative hyperconjugation is also known as anomeric effect [2]. In anomeric effect, both donor (lone pairs) and acceptor groups (electronegative elements) coex...
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