Browsing Faculty of Science by Author "Keumedjio, F."
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Ngadjui, B.T.; Abegaz, B.M.; Keumedjio, F.; Folefoc, G.N.; Kapchec, G.W.F. (Elsevier Science Ltd. www.elsevier.com/locate/phytochem, NaN, 2002)[more][less]
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: 7b-acetoxytrachyloban-18-oic acid and trachyloban-7b, 18-diol. Betulinol, lupeol, sitosterol and its 3b-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-19,1a:20,12-diolide-18-oic acid methylester, using spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HSQC, HMBC and TOCSY. URI: http://hdl.handle.net/10311/251 Files in this item: 2
Diterpenoids from the stem bark.pdf (2.493Mb)license.txt (1.998Kb) -
Ngadjui, B.; Watchueng, J.; Keumedjio, F.; Ngameni, B.; Simo, I.; Abegaz, B. (Elsevier Ltd. www.elsevier.com/locate/phytochem, NaN, 2004)[more][less]
Abstract: The twigs of Dorstenia angusticornis and Dorstenia barteri var. subtriangularis yielded 16 compounds. Two novel diprenylated chalcones: 3,50-di-(2-hydroxy-3-methylbut-3-enyl)-4,20,40-trihydroxychalcone, 3, 4-(2,2-dimethylpyrano)-30-(2-hydroxy-3-methylbut- 3-enyl)-20,40-dihydroxychalcone and the known stipulin were isolated from both species. 3-(2-Hydroxy-3-methylbut-3-enyl)- 50-(3,3-dimethylallyl)-4,20,40-trihydroxychalcone and the known compounds: 4-hydroxylonchocarpin, kanzonol B, bartericins A, B, C and 30-(2-hydroxy -3-methylbut-3-enyl)-4,20,40-trihydroxychalcone were isolated from D. barteri while the known compounds: gancaonin Q, paratocarpins C, F, and lupeol were obtained from Dorstenia angusticornis. b-Sitosterol and its b-D-glucopyranoside were isolated from both species. Structures of these secondary metabolites were established using spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HMQC and HMBC. URI: http://hdl.handle.net/10311/253 Files in this item: 2
license.txt (1.998Kb)Prenylated chalcones, flavone.pdf (3.563Mb)
Now showing items 1-2 of 2