title: [Further Helenanolides from the Flowers of Arnica chamissonis subsp. foliosa].
abstract: A phytochemical study of the flowers of ARNICA CHAMISSONIS Less. subsp. FOLIOSA (Nutt.) Maguire (Asteraceae) has resulted in the identification of a further 23 helenanolides. Six of them, 2alpha-hydroxy-6- O-angelicoyl-2,3-dihydrohelenalin ( 3B), 2alpha-hydroxy-6- O-senecioyl-2, 3-dihydrohelenalin ( 3C), 2alpha-hydroxy-6- O-tigloyl-2,3,11alpha,13-tetrahydrohelenalin ( 4A), 2alpha-hydroxy-6- O-isovaleryl-2, 3,11alpha,13-tetrahydrohelenalin ( 4D), 6- O-acetylchamissonolide ( 5C), and 4,6-di- O-acetylchamissonolide ( 5D), were isolated for the first time as natural compounds. Their structures were established by GLC-MS studies and IR, (1)H- and (13)C-NMR spectroscopy.
authors.affiliation: Institut für Pharmazeutische Biologie der Heinrich-Heine-Universität Düsseldorf, Universitätsstr.1, D-4000 Düsseldorf, Federal Republic of Germany.
authors.forename: G
authors.initials: G
authors.lastname: Willuhn
authors.forename: J
authors.initials: J
authors.lastname: Kresken
authors.forename: W
authors.initials: W
authors.lastname: Leven