title: Grahamines A-E, cyclobutane-centered tropane alkaloids from the aerial parts of Schizanthus grahamii.
abstract: Schizanthus grahamii is an endemic Chilean plant that is known to contain tropane alkaloids. Five new alkaloids, grahamines A-E (1-5), were isolated and characterized by extensive spectroscopic analysis. Their structures were determined to be 2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylic acid (1), 2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-tigloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylic acid (2), 1-methyl-2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-4-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-3-phenylcyclobutanecarboxylic acid (3), 1,2-bis{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylate (4), and 1-{[(3α-mesaconyloxytropo-6β-yl)oxy]carbonyl}-2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylate (5).
authors: School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland.
authors: Sylvian
authors: S
authors: Cretton
authors: Trixie A
authors: TA
authors: Bartholomeusz
authors: Munir
authors: M
authors: Humam
authors: Laurence
authors: L
authors: Marcourt
authors: Yves
authors: Y
authors: Allenbach
authors: Damien
authors: D
authors: Jeannerat
authors: Orlando
authors: O
authors: Muñoz
authors: Philippe
authors: P
authors: Christen
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification*; D002677:Chile; D003503:Cyclobutanes / Q000737:chemistry*; D015394:Molecular Structure; D019657:Solanaceae / Q000737:chemistry*; D013237:Stereoisomerism; D014326:Tropanes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D000470:Alkaloids; D003503:Cyclobutanes; D014326:Tropanes