نتایج جستجو برای: epoxy compounds
تعداد نتایج: 239236 فیلتر نتایج به سال:
Three new chalcanol glucosides have been isolated from the seeds of Trifolium alexandrinum, of which the first two are alpha'-chalcanol-alpha, beta-epoxides and the third one is an alpha, beta-dihydroxy-alpha'-chalcanol. The structures of the isolated compounds were verified by means of MS and 2D NMR spectral analyses.
A facile one-pot two-step process for the synthesis of 1,3-thiazole heterocycles via organocatalytic epoxidation of nitro-olefins with the t-BuOOH/DBU system, and subsequent reaction of α-nitro-epoxides with thioamides under mild conditions has been developed.
Recent work has demonstrated that isoprene-derived epoxide intermediates are responsible for a wide variety of chemical species found in ambient secondary organic aerosol (SOA). Since the second most abundant biogenic hydrocarbon, α-pinene, is also known to form an epoxide intermediate, nuclear magnetic resonance techniques were used to study products, kinetics, and equilibria of the aqueous ph...
A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions
Complex amino acids with an α-acyloxycarbonyl functionality in the side chain are easily available through epoxide opening by chelated enolates and subsequent oxidation/Passerini reaction. This protocol works with both, aldehyde and ketone intermediates, as long as the ketones are activated by electron-withdrawing groups. In principle Ugi reactions are also possible, allowing the generation of ...
The key steps in the synthesis of clavulactone are formation of an enantiopure cyclopentane precursor by epoxide rearrangement and intramolecular carbonyl-ene reaction, construction of the 3,4-dihydro-2H-pyran ring by intermolecular hetero-Diels-Alder reaction, closure of the eleven-membered ring, and finally generation of the lactone functionality by chemoselective allylic C(sp(3))-H oxidation.
This review article focuses on the recent applications of tris(trimethylsilyl)silane as a radical-based reagent in organic chemistry. Numerous examples of the successful use of (TMS)(3)SiH in radical reductions, hydrosilylation and consecutive radical reactions are given. The use of (TMS)(3)SiH allows reactions to be carried out under mild conditions with excellent yields of products and remark...
An efficient asymmetric synthesis of cyclo-archaeol and β-glucosyl cyclo-archaeol is presented employing catalytic asymmetric conjugate addition and catalytic epoxide ring opening as the key steps. Their occurrence in deep sea hydrothermal vents has been confirmed by chromatographic comparison with natural samples.
Four possible stereoisomers of 3-hydroxy-4-methyltetradecanoic acid were enantioselectively synthesized by using Sharpless epoxidation and a subsequent epoxide-ring opening reaction with trimethylaluminum as the key steps. The absolute configuration of the beta-oxyacid component of antifungal cyclodepsipeptides W493 A and B was consequently determined as 3S,4R.
The kinetic mechanism of epoxide hydrolase (EC 3.3.2.3) from potato, StEH1 (Solanum tuberosum epoxide hydrolase 1), was studied by presteady-state and steady-state kinetics as well as by pH dependence of activity. The specific activities towards the different enantiomers of TSO (trans-stilbene oxide) as substrate were 43 and 3 micromol x min(-1) x mg(-1) with the R,R- or S,S-isomers respectivel...
whether the well-known fatty acids, the nutritional qualities and safety of which are taken for granted, have any car cinogenic effects. Not only are we interested in the carcinogenicity of oxidation products as described above, but, perhaps more important, we are searching for functional group-biological activity relationships. In this paper we report a preliminary study of the carcinogenicity...
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