title: Germacranolides and a new type of guaianolide from Acanthospermum hispidum.
abstract: The aerial parts of an Argentinian collection of Acanthospermum hispidum afforded 26 sesquiterpene lactones, including the two guaianolides (1 and 2) having a novel oxygen bridge between C-4 and C-14, three new cis,cis-germacranolides (4, 7, and 8), and two new melampolides (25 and 26). Guaianolides 1 and 2 seem to derive biosynthetically from the germacranolide 27 having the (1)D(14, 15)D(5) conformation. The structures were elucidated using extensive spectroscopic analysis.
authors.affiliation: Instituto de Química Orgánica, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 491, S. M. de Tucumán 4000, Argentina.
authors.forename: E
authors.initials: E
authors.lastname: Cartagena
authors.forename: A
authors.initials: A
authors.lastname: Bardón
authors.forename: C A
authors.initials: CA
authors.lastname: Catalán
authors.forename: Z N
authors.initials: ZN
authors.lastname: de Hernández
authors.forename: L R
authors.initials: LR
authors.lastname: Hernández
authors.forename: P
authors.initials: P
authors.lastname: Joseph-Nathan
mesh_terms: D001118:Argentina; D004952:Esters / Q000737:chemistry / Q000302:isolation & purification*; D005663:Furans / Q000737:chemistry / Q000302:isolation & purification*; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D019684:Magnoliopsida / Q000737:chemistry*
chemical_list: D004952:Esters; D005663:Furans; D007783:Lactones; C017879:germacanolide; C416425:hispidunolide A; C416426:hispidunolide B