Sesquiterpenoid constituents of the liverwort Marsupella aquatica

Nine new amorphane sesquiterpenoids, (+)-7 beta-hydroxyamorpha-4,11-diene, (-)-9 alpha-hydroxyamorpha-4,7(11)-diene, (-)-3 alpha-hydroxyamorpha-4,7(11)-diene, (-)-3 alpha-acetoxyamorpha-4,7(11)-diene, (-)-amorpha-4,7(11)-dien-3-one, (+)-2,8-epoxyamorpha-4,7(11)-diene, (+)-5,9-epoxyamorpha-3,7(11)-diene, (-)-2 alpha-hydroxyamorpha-4,7(11)-diene and (-)-2 beta-acetoxyamorpha-4,7(11)-diene, were isolated from the essential oil of the liverwort Marsupella aquatica, collected near Gaschurn/Montafon, Austria. The isolated compounds and their chemical transformations were investigated using enantioselective GC and extensive spectroscopic studies (HRMS, H-1, C-13 and 2D NMR). The absolute configuration of most of the isolated compounds were established by conversions to known compounds. In addition, H-1, and C-13 NMR data of (-)-myltayl-4-ene are reported for the first time. (C) 2007 Elsevier Ltd. All rights reserved.