| 词条 | Nitrone |
| 释义 |
Generation of nitronesNitrones are generated most often either by the oxidation of hydroxylamines or condensation of monosubstituted hydroxylamines with carbonyl compounds (ketones or aldehydes). The most general reagent used for the oxidation of hydroxylamines is mercury(II) oxide.[2] Carbonyl condensation methods avoid issues of site selectivity associated with the oxidation of hydroxylamines with two sets of (alpha) hydrogens.[3] A significant problem associated with many reactive nitrones is dimerization.[4] This issue is alleviated experimentally by employing an excess of the nitrone or increasing the reaction temperature to exaggerate entropic factors. Reactions1,3-dipolar cycloadditions{{Main|Nitrone-olefin 3+2 cycloaddition}}As 1,3-dipoles, nitrones are useful in 1,3-dipolar cycloadditions.[1] Upon reaction of a nitrone with an alkene dipolarophile, an isoxazolidine is formed: See also
References1. ^1 {{cite journal|last=Yang|first=Jiong|title=Recent Developments in Nitrone Chemistry|journal=Synlett|year=2012|volume=23|page=2293-97|doi=10.1055/s-0032-1317096}} 2. ^{{cite journal|last1=Thiesing|first1=Jan|last2=Mayer|first2=Hans|title=Cyclische Nitrone, II. Über die Polymeren des 2.3.4.5-Tetrahydro-pyridin-N-oxyds und verwandte Verbindungen|journal=Justus Liebigs Ann. Chem.|year=1957|volume=609|page=46-57|doi=10.1002/jlac.19576090105}} 3. ^{{cite journal|last=Exner|first=O.|title=A New Synthesis of N-methylketoximes|journal=Collect. Czech. Chem. Commun.|year=1951|volume=16|page=258-267|doi=10.1135/cccc19510258}} 4. ^{{cite journal|last1=Thiesing|first1=Jan|last2=Mayer|first2=Hans|title=Cyclische Nitrone I: Dimeres 2.3.4.5-Tetrahydro-pyridin-N-oxyd|journal=Chem. Ber.|year=1956|volume=89|page=2159-2167|doi=10.1002/cber.19560890919}} 1 : Functional groups |
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