Imperialine β-N-oxide 3 isolated from the bulbs of fritillaria siechuanica S. C. Che was identified on the basis of the chemical and spectral methods. Its all ^1H and ^!^3C-signals have been assigned unambigously based on studies of 2D NMR. In addition, assigments of the chemical shifts of some ^!^3C-signals of 3 reported in literature 4 were revised.

Key words: PEIMINE, 2D NMR SPECTROMETRY, NITROGEN OXIDE