Herbertane sesquiterpenoids from the liverworts Herbertus aduncus and H-borealis

Two new herbertane sesquiterpenoids, (-)-1,2-dihydroxyherberten-12-al and methyl 1,2-dihydroxyherberten-12-oate, were isolated from the liverwort Herbertus aduncus ssp. hutchinsiae together with herbertene, alpha-herbertenol. beta-herbertenol, and herbertene-1,2-diol. Their structures were established by spectroscopic methods, especially NMR spectroscopy. Herbertene and alpha-herbertenol were identified in H. borealis on analysis by GC and H-1 NMR. The early development of the identification of herbertane rather than cuparane sesquiterpenoids in H. aduncus is reviewed critically, and attention is drawn to the fact that, despite already being recognized as being obsolete, an early report concerning the occurrence of a cuparenediol in Herbertus species has been promulgated in a recent review. Copyright (C) 1996 Elsevier Science Ltd