title: Short side chain sterols from the tunicate Polizoa opuntia.
abstract: The sterol composition of the Patagonian tunicate Polizoa opuntia was examined, and twenty-four compounds were identified as having either a delta 5, delta 7, or delta 0 nucleus. Two of them, the rare 20-methylpregn-5-en-3 beta-ol and 20-ethylpregn-5-en-3 beta-ol, were previously unreported as natural products from tunicates. These compounds were present only as trace components; therefore, their structures were confirmed by synthesis from suitable precursors and by comparison of the spectral and chromatographic constants of the synthetic and natural compounds.
authors.affiliation: Departamento de Química Orgánica, Universidad de Buenos Aires, Argentin
authors.forename: J A
authors.initials: JA
authors.lastname: Palermo
authors.forename: M F
authors.initials: MF
authors.lastname: Brasco
authors.forename: E A
authors.initials: EA
authors.lastname: Hughes
authors.forename: A M
authors.initials: AM
authors.lastname: Seldes
authors.forename: V T
authors.initials: VT
authors.lastname: Balzaretti
authors.forename: E
authors.initials: E
authors.lastname: Cabezas
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008968:Molecular Conformation; D013056:Spectrophotometry, Ultraviolet; D013261:Sterols / Q000737:chemistry*; D014561:Urochordata / Q000737:chemistry*
chemical_list: D013261:Sterols