Abstract
As a continuation of the study on the lichen triterpenoids, the neutral triterpenoids of a lichen Pyxine endochrysina NYL. have been investigated. The structure of diacetylpyxinol, a major component, has been established as 3β, 25-diacetoxy-12β-hydroxy-20 (S), -24 (R)-epoxy-dammarane (II) on the basis of the chemical evidence and the X-ray analysis.In addition, the other minor neutral components have also been elucidated as pyxinol (III), 12-desoxy-diacetylpyxinol (IV), 3-O-acetyl-pyxinol (V), methyl pyxinate (VI), and methyl 3-O-acetyl-pyxinate (VII), among which the latter two compounds possess the hopane skeleton.
Diacetylpyxinol and the analogues are the first examples of the dammarane triterpenoids discovered in the lichen family.
