title: Diterpenoids from the stem bark of Croton zambesicus.
abstract: Three clerodane diterpenoids, crotozambefurans A, B and C were isolated from the stem bark of Croton zambesicus together with the known clerodane crotocorylifuran and two trachylobanes: 7 beta-acetoxytrachyloban-18-oic acid and trachyloban-7 beta, 18-diol. Betulinol, lupeol, sitosterol and its 3 beta-glucopyranosyl derivative were also obtained. The structures of crotozambefurans A, B and C were determined, respectively, as: 15,16-epoxy-1,3,13(16),14-clerodatetraen-20,12-olide-18,19-dioic acid dimethylester, 15,16-epoxy-1,3,13(16),14-clerodatetraen-18,19,20-trioic acid trimethylester and 15,16-epoxy-3,13(16),14-clerodatrien-19,1 alpha:20,12-diolide-18-oic acid methylester, using spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HSQC, HMBC and TOCSY.
authors.affiliation: Department of Organic Chemistry, University of Yaounde 1, BP 812, Yaounde, Cameroon. bngadjui@uycdc.uninet.cm
authors.forename: Bonaventure T
authors.initials: BT
authors.lastname: Ngadjui
authors.forename: Berhanu M
authors.initials: BM
authors.lastname: Abegaz
authors.forename: Felix
authors.initials: F
authors.lastname: Keumedjio
authors.forename: Gabriel N
authors.initials: GN
authors.lastname: Folefoc
authors.forename: Gilbert W F
authors.initials: GW
authors.lastname: Kapche
mesh_terms: D002163:Cameroon; D002845:Chromatography / Q000379:methods; D029802:Croton / Q000737:chemistry*; D004224:Diterpenes / Q000737:chemistry*; D005663:Furans / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism
chemical_list: D004224:Diterpenes; D005663:Furans; D010936:Plant Extracts