An NMR study of conformational behaviour and nitrogen inversion process in some 5,5-disubstituted-beta-phenyl-2-isoxazolidineethanols

作者：Ali Shaikh A^*; Iman Muhammad Z N; Wazeer Mohamed I M

来源：Canadian Journal of Analytical Sciences and Spectroscopy, 2008, 53(2): 66-74.

• Isoxazoldines
• Nitrogen inversion
• Invertomers
• Inversion barriers

A series of (beta R, 5R)- and (beta R, 5S)-2,5,5-trisubstituted isoxazolidines: 5-methyl-5-(substituent)-beta-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 (beta R, 5S) diasteromer almost exclusively as a single invertomer having cis disposition of the substituents at N(2) and C(5)-methyl, while the (beta R, 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.

• 出版日期2008
• 单位中国石油大学（北京）