title: Study of inversion isomerism in some 4,5-cis-substituted-2-isoxazolidineethanols by NMR spectroscopy.
abstract: A series of beta-phenyl-2-isoxazolidineethanols having cis-disposed substituents at C(4) and C(5) has been prepared by asymmetric nitrone cycloaddition reactions and their NMR spectra recorded over a wide range of temperatures. The spectra in CDCl3 at low temperatures indicate the presence of two interconverting invertomers for some of the tri-substituted isoxazolidines. The effect of H-bonding--intramolecular in CDCl3 and intermolecular in CD3OD--on the population ratio of the nitrogen invertomers has been investigated. The nitrogen inversion barriers are determined using complete line-shape analysis, and their dependence on solvent is discussed.
authors.affiliation: Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. shaikh@kfupm.edu.sa
authors.forename: Shaikh A
authors.initials: SA
authors.lastname: Ali
authors.forename: Mohamed I M
authors.initials: MI
authors.lastname: Wazeer
mesh_terms: D000431:Ethanol / Q000737:chemistry*; D006860:Hydrogen Bonding; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry; D010080:Oxazoles / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D013816:Thermodynamics
chemical_list: D009589:Nitrogen Oxides; D010080:Oxazoles; D012997:Solvents; C015388:nitrones; D000431:Ethanol; D009584:Nitrogen; D010100:Oxygen