Sesquiterpene constituents from the liverwort Bazzania japonica

The hydrodistillation products of the liverwort Bazzania japonica were separated by preparative gas chromatography (GC) and investigated by spectroscopic methods. Seven unknown compounds were isolated and identified by GC-MS and NMR. Four of them, the norsesquiterpene hydrocarbons 4-epi-11-nor-aristola-1(10),11-diene (1), 4-epi-11-nor-aristola-1,9,11-triene (2), 4-epi-11-nor-aristola-9,11-diene (3), and one oxygenated sesquiterpene, (-)-aristol-1(10)-en-12-ol (5) are new natural compounds, and one, (+)-himachala-2,4-diene (7), has for the first time been isolated from liverworts. The absolute configurations of 5 and 7 were derived by chemical correlation reactions and/or enantioselective GC using cyclodextrin phases. 1, 2 and 3 have identical absolute configuration.