Publications by authors named "Ursula Hertewich"

NMR studies have shown that seven new sesquiterpenoids, 3, 4, 5a, and 7-10, isolated from dried samples of the New Zealand liverwort Lepidolaena hodgsoniae have the same substituted cyclopentapyran ring system as the previously described insecticidal sesquiterpene diene hodgsonox (1), which has been reported only from this plant. In all but one compound, 10, the 1,1-disubstituted double bond of hodgsonox has migrated into an endocyclic position, but only two, 5a and 9, have the double bonds in conjugation. These seven new compounds represent a variety of different oxidation levels.

View Article and Find Full Text PDF

Five new sacculatane diterpenoids, 17,18-epoxy-7-sacculaten-12,11-olide, 7,17-sacculatadien-11,12-olide, 11beta,12-epoxy-7,17-sacculatadien-11alpha-ol, 1beta-acetoxy-11beta,12-epoxy-7,17-sacculatadien-11alpha-ol and 1beta,15xi-diacetoxy-11,12-epoxy-8(12),9(11),17-sacculatatriene along with sacculatal and sacculatanolide have been isolated from axenic cultures of the liverwort Fossombronia wondraczekii and their structures assigned on the basis of their spectroscopical properties.

View Article and Find Full Text PDF

Six new labdane type diterpenoids, three seco-clerodane diterpenoids, jamesoniellide I, along with the two new jamesoniellides K and L, the sesquiterpene waitziacuminone and a new chlorinated bisbibenzyl, 6,6',10,10',12,12'-hexachloroisoperrottetin A, have been isolated from the liverwort Jamesoniella colorata. Their structures were elucidated by NMR spectroscopy. The absolute configuration of 3-oxo-labda-8(17),13(16),14-triene (1) was established by CD spectroscopy.

View Article and Find Full Text PDF