Eremophilanolides and other constituents from the Argentine liverwort Frullania brasiliensis.

Two eremophilanolides, 5-epidilatanolides A and B, as well as a new natural bibenzyl were isolated from an Argentine collection of the liverwort Frullania brasiliensis, along with the known eudesmane-type sesquiterpene lactones nepalensolide A, nepalensolide B, (+)-frullanolide, and (+)-dihydrofrullanolide, the hopanoid zeorin, the four sterols stigmasta-4,22-dien-3,6-dione, stigmasta-4,22-dien-3-one, stigmasterol, and sitosterol, and a trace amount of atraric acid. The structure and stereochemistry of the eremophilanolides and the bibenzyl were established by a combination of extensive NMR spectroscopy experiments and X-ray crystallographic analysis. Absolute configurations of the new compounds were derived on the basis of CD spectra.