1972 Volume 20 Issue 1 Pages 147-156
Taking into the consideration of the established structures of two coexisting lichen triterpenoids, leucotylin (I) and zeorin (II), the re-investigation on the chemical correlation between leucotylin and ezorin has been undertaken. It has been elucidated that the authors' previous proposal on the structures of zeorin (II*), hopane (III*), and isohopane (XXI*) should be abandoned and the final conclusion on the stereostructure of zeorin (II) in addition to its correlation with leucotylin (I) has been presented. Furthermore, the structure of isoleucotylin (XXXVI), derivable from leucotylin along with leucotylidiene (XXXV) under the acid treatment, has been elucidated.