Lichen Triterpenoids. I. The Structure of Leucotylin

Abstract

The structure of leucotylin, one of the major triterpenoids of a lichen Parmelia leucotyliza NYL., has been established as I on the basis of chemical and X-ray crystallographical investigations. It has also been suggested that zeorin, another major triterpenoid of the same lichen, has a similar carbon skeleton as leucotylin but differs at the C₂₁ orientation as is expressed by II.