- Efficient synthesis of D6-clenproperol and D6-cimaterol using deuterium isopropylamine as labelled precursor
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This report presents an efficient synthesis of D6-clenproperol and D6-cimaterol with 99.5% and 99.7% isotopic abundance in acceptable yields and excellent chemical purities with deuterium isopropylamine as labelled precursor. Their structures and the isotope-abundance were confirmed by proton nuclear magnetic resonance and liquid chromatography–mass spectrometry.
- Sun, Kai,Fang, Chao,Yang, Weicheng,Xu, Zhongjie,Wang, Haoran,Sun, Wen,Luo, Yong,Xu, Yi
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p. 552 - 556
(2016/11/23)
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- Rearrangements in Metastable Ion Decompositions of Protonated Propylamines
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Decomposition of nPrNH3(+) to NH4(+) does not occur via vicinal elimination.Hydrogen transfer takes place from all positions of the alkyl chain.Intermediacy of either an ion-neutral complex, , or rearrangement to iPrNH3(+) is required.SCF calculations were used to probe the potential energy surface.There is a minimum corresponding to , in which the nitrogen lone pair points towards the machine hydrogen and is 2.1 Angstroem away from it, and another, less stable, minimum corresponding to a hydrogen-bonded structure, H3N ...H3CCHCH3(+), in which one methyl hydrogen is 2.0 Angstroem from the nitrogen.Density of states estimates suggest that a vibrationally excited complex can live for the order of 100 ps before either collapsing to iPrNH3(+) or yielding NH4(+) and propene.
- Audier, Henri E.,Morton, Thomas Hellman
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p. 1218 - 1224
(2007/10/02)
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- The Collision-Induced Dissociations of Deprotonated Amines in the Gas Phase
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The major collision-induced fragmentations of deprotonated primary and secondary amines are best rationalized as proceeding through the intermediacy of ion complexes.For example, the characteristic fragmentation of deprotonated ethylamine is MeCH2NH- -> -(CH2=NH)> -> CH2N- + CH4 Secondary alkylamines behave in a similar fashion.The occurrence of proton transfer as a prelude to fragmentation is rare: the only example observed in this study is the probable reaction PhNEt ->-> PhNHCHMe -> -> -> C7H6N- + CH4 which is preceded or accompanied by proton transfer between the methylene and phenyl substituents.Deprotonated aniline undergoes specific elimination of CNH from the 1-position to form the cyclopentadienyl anion.Finally, retro reactions are observed for the piperazine anion, e.g.HN(CH2CH2)2N- -> -CH2CH2N=CH2 + CH2NH
- Raftery, Mark J.,Bowie, John H.
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p. 1477 - 1489
(2007/10/02)
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