title: 11Alpha,13-and 11beta,13-dihydro-4H-xanthalongin 4-O-beta-glucopyranosides: new sesquiterpene lactone glycosides from flowers of Arnica amplexicaulis and A. mollis.
abstract: The flowers of A. amplexicaulis afforded, in addition to xanthalongin ( 1), 11beta,13-dihydroxanthalongin (2), its 11-epimer (3), and 11alpha,13-dihydro-4H-xanthalongin (4), the new xanthanolide glycosides 11alpha, 13-dihydro-4 H-xanthalongin 4- O-beta-D-glucopyranoside (5) and its 11-epimer (6). The glycosides were also isolated from the flowers of A. mollis. The structures were elucidated by NMR spectroscopy (1)H-NMR, COSY, (13)C-NMR, HETCOR, DEPT), MS (EI, FAB, FD), and enzymatic hydrolysis of the glycosides. The chemo-taxonomic importance is discussed.
authors.affiliation: Institut für Pharmazeutische Biologie, Heinrich-Heine-Universität Düsseldorf, Geb. 26.23, Universitätsstr. 1, D-40225 Düsseldorf, Germany.
authors.forename: C M
authors.initials: CM
authors.lastname: Passreiter
authors.forename: I
authors.initials: I
authors.lastname: Merfort
authors.forename: C
authors.initials: C
authors.lastname: Bestendonk
authors.forename: G
authors.initials: G
authors.lastname: Willuhn
authors.forename: A
authors.initials: A
authors.lastname: Steigel