title: Novel cassane and cleistanthane diterpenes from Myrospermum frutescens: absolute stereochemistry of the cassane diterpene series.
abstract: Four new diterpenes (1-4) were isolated from the leaves of Myrospermum frutescens as minor constituents. Chagresnol (1), 6beta,18-diacetoxycassan-13,15-diene (2), and chagreslactone (3) possess cassane skeletons, while chagresnone (4) exhibits a cleistanthane skeleton. Molecular structures and their relative stereochemistries were elucidated using NMR spectroscopy in combination with UV, IR, and MS spectral data. Although compound 2 was previously reported as a synthetic product, we report its first isolation as a natural product. Derivative products (10-13) were obtained to test their activities against Chagas's disease. In addition, the absolute stereochemistry of the previously isolated cassane diterpene 5 from M. frutescens is presented.
authors.affiliation: Laboratory of Tropical Bioorganic Chemistry, Faculty of Natural, Exact Sciences and Technology, Apartado 0824-10835, University of Panama, Panama City, Republic of Panama.
authors.forename: Daniel
authors.initials: D
authors.lastname: Torres-Mendoza
authors.forename: Luis David
authors.initials: LD
authors.lastname: Ureña González
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ortega-Barría
authors.forename: Phyllis D
authors.initials: PD
authors.lastname: Coley
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kursar
authors.forename: Todd L
authors.initials: TL
authors.lastname: Capson
authors.forename: Kerry
authors.initials: K
authors.lastname: McPhail
authors.forename: Luis
authors.initials: L
authors.lastname: Cubilla-Rios
mesh_terms: D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy*; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007887:Fabaceae / Q000737:chemistry*; D013058:Mass Spectrometry; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014344:Trypanocidal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D004224:Diterpenes; D014344:Trypanocidal Agents