Two new sesterterpene tetronic acids from the marine sponge Ircinia oros

@inproceedings{Hoeller1997TwoNS,
  title={Two new sesterterpene tetronic acids from the marine sponge Ircinia oros},
  author={Ulrich Hoeller and Gabriele M. K{\"o}nig and Anthony D. Wright},
  year={1997}
}
Two new sesterterpene tetronic acids, (8Z,13Z,18S,20Z)-strobilinin (1) and (7E,12Z,18S,20Z)-variabilin (3), together with the known compounds (7E,12E,18S,20Z)-variabilin (5), (7E,13Z,-18S,20Z)-variabilin (7), and (7Z,12Z,20Z)-variabilin (9), have been isolated from the sponge Ircinia oros as their 22-O-methyl derivatives 2, 4, 6, 8, and 10. The structures of all compounds were determined by spectroscopic methods, mainly 1D and 2D NMR methodologies.