Abstract: | Dibothrioclinin I and II, namely (+)‐(11R,12S,25R,27S)‐ and (±)‐(11RS,12RS,25RS,27SR)‐3,3,7,17,21‐pentamethyl‐4,12,18,26‐tetraoxaheptacyclo15.11.1.02,15.05,14.06,11.019,28.020,25]nonacosa‐5(14),6,8,10,19(28),20,22,24‐octaene‐13,27‐dione, respectively, are C30H28O6 epimers which are derived from two bothrioclinin moieties joined so as to create an additional six‐membered ring. Structurally, the epimers differ only by inversion at one C atom of a central ring junction and the corresponding six‐membered rings have similar conformations in each molecule, except for one ring adjacent to this inversion site. |