- Understanding the Alkylation Mechanism of 3-Chloropiperidines – NMR Kinetic Studies and Isolation of Bicyclic Aziridinium Ions
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The present study describes the kinetic analysis of the 3-chloropiperidine alkylation mechanism. These nitrogen mustard-based compounds are expected to react via a highly electrophilic bicyclic aziridinium ion, which is readily attacked by nucleophiles. Halide abstraction using silver salts with weakly coordinating anions lead to the isolation of these proposed intermediates, whereas their structure was confirmed by single crystal XRD. Kinetic studies of the aziridinium ions also revealed notable reactivity differences of the C5 gem-methylated compounds and their unmethylated counterparts. The observed reactivity trends were also reflected by NMR studies in aqueous solution and DNA alkylation experiments of the related 3-chloropiperidines. Therefore, the underlying Thorpe-Ingold effect might be considered as another option to adjust the alkylation activity of these compounds.
- Helbing, Tim,Georg, Mats,St?hr, Fabian,Carraro, Caterina,Becker, Jonathan,Gatto, Barbara,G?ttlich, Richard
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p. 5905 - 5913
(2021/10/29)
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- Rearrangement of β-chloro N-oxides to hydroxylamines: Opening of the oxazetidinium intermediate by different nucleophiles
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The rearrangement of β-chloro N-oxides to hydroxylamines is stereospecific in accord with the presence of a cyclic oxazetidinium intermediate. The latter opens with a range of nucleophiles (carboxylates, cyanide, azide, and thiols)
- Wefelscheid, Ulrike K.,Woodward, Simon
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supporting information; experimental part
p. 2254 - 2256
(2009/08/07)
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- Ring expansion - Formation of optically active 3-hydroxypiperidines from pyrrolidinemethanol derivatives
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Treatment of pyrrolidinemethanol derivatives (-)-1, (-)-6, (-)7, 8, (- )-9, (+)-10, (-)-11, and (-)-21 with trifluoroacetic anhydride and then with Et3N afforded, after hydrolysis of the trifluoroacetyl group with NaOH, the optically active -hy
- Cossy, Janine,Dumas, Cecile,Gomez Pardo, Domingo
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p. 1693 - 1699
(2007/10/03)
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