کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1234478 | 968828 | 2008 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
2-Isoxazolidineethanols: An NMR study of the effect of intramolecular H-bonding on the population of nitrogen invertomers and inversion process
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
A series of (βR,5R)- and (βR,5S)-2,5-disubstituted isoxazolidines: 5-(substituent)-β-phenyl-2-isoxazolidineethanols, have been prepared by asymmetric nitrone cycloaddition reactions and their NMR spectra recorded over a wide range of temperatures. The spectra at low temperatures indicate the presence of the (βR,5S) diasteromer almost exclusively as a single invertomer having trans disposition of the substituents at N(2) and C(5), while the (βR,5R) diasteromer remained as a mixture of two interconverting invertomers in deuterated chloroform. The effect of H-bonding - intramolecular in CDCl3 and intermolecular in CD3OD - on the population ratio of the invertomers and nitrogen inversion process has been investigated. The nitrogen inversion barriers are determined using complete line-shape analysis, and their dependence on solvent is discussed. Due to steric factor the trans-invertomers are found to be more stable than their cis counterparts.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 70, Issue 3, August 2008, Pages 482-490
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 70, Issue 3, August 2008, Pages 482-490
نویسندگان
Shaikh A. Ali, Muhammad Z.N. Iman, Mohamed I.M. Wazeer, Mohammed B. Fettouhi,