SPECTROSCOPY LETTERS, vol.25, no.4, pp.559-564, 1992 (SCI-Expanded)
C-13 NMR spectra of lumisantonin (2), isosantoxane (3a), its acetyl derivative (3b) and santonic acid (4) are reported. The structure of a novel photo derivative (6) is established on the basis of spectroscopic methods, particularly C-13 NMR spectra.