Quirogane, prenopsane, and patzcuarane skeletons obtained by photochemically induced molecular rearrangements of longipinene derivatives

J Nat Prod. 2002 Oct;65(10):1398-411. doi: 10.1021/np020158s.


Ultraviolet irradiation of (1R,3S,4S,5S,10R,11R)-1-acetyloxy-7-oxolongipin-8-ene (6), prepared from longipinene diesters isolated from Stevia salicifolia, afforded the new quirogane (7) and prenopsane (8) derivatives, as the major products, together with the minor secondary photoproduct (1R,3R,5R,8S,11S)-1-acetyloxy-7-oxopatzcuar-9-ene (9), which possesses a novel tricyclic sesquiterpene skeleton. The stereostructures of the new compounds 7-9 were mainly determined by NMR techniques including COSY, HSQC, HMBC, and NOESY in combination with molecular modeling obtained by density functional theory calculations. A reaction mechanism accounting for the observed transformations is proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Photochemistry
  • Sesquiterpenes / chemistry*
  • Spectrum Analysis
  • Stevia / chemistry*


  • Sesquiterpenes
  • patzcuarane
  • prenopsane
  • quirogane
  • longipinene