title: Structure determination of ursene-type triterpenes by NMR techniques.
abstract: Two new ursene-type triterpenes, nudicauline A and nudicauline B, have been isolated from Launaea nudicaulis. Their structures have been assigned as 3beta-hydroxy-urs-11-ene (1) and 3beta-acetyl-urs-11-ene (2), respectively, by extensive NMR studies. In addition, olean-11,13(18)-diene (3), 3beta-hydroxy-13(28)-epoxy-urs-11-ene (4) and 3-keto-13(28)-epoxy-urs-11-ene (5) are also reported for the first time from this species.
authors.affiliation: International Center for Chemical Sciences, H.E.J. Research Institute of Chemistry, University of Karachi, 75270-Karachi, Pakistan. zaheer_hej@mail.com
authors.forename: Zaheer
authors.initials: Z
authors.lastname: Ahmed
authors.forename: Dildar
authors.initials: D
authors.lastname: Ali
authors.forename: Abdul
authors.initials: A
authors.lastname: Malik
mesh_terms: D019659:Asteraceae / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D035261:Plant Components, Aerial / Q000737:chemistry; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification*; D000097245:Ursolic Acid
chemical_list: D014315:Triterpenes; D000097245:Ursolic Acid