Mag. Res. Chem. 43, 1040-1043 (2005)

Doi: 10.1002/mrc.1676

The structure of the products of condensation of hydroxylamine with trifluoromethyl-b-diketones: assignments of the diastereotopic protons of the 4-methylene group in 5-hydroxy-5-trifluoromethyl-D2-isoxazolines

The combined use of 1H NMR spectroscopy with theoretical calculations of chemical shifts (GIAO) and coupling constants (B3LYP/6-311 ++G**) of a 5-hydroxy-5-trifluoromethyl-Δ2-isoxazoline has enabled solving the problem of the assignments of the diastereotopic protons in this compound. This result has been extended to 5-hydroxy-5-trifluoromethyl-Δ2-pyrazolines and the corresponding 5-trichloromethyl derivatives.