Diprenylated chalcones and other constituents from the twigs of Dorstenia barteri var. subtriangularis.
The twigs of Dorstenia barteri var. subtriangularis yielded three diprenylated chalcones: (-)-3-(3,3-dimethylallyl)-5'-(2-hydroxy-3-methylbut-3-enyl)-4,2',4'-trihydroxychalcone, (+)-3-(3,3-dimethylallyl)-4',5'-[2'''-(1-hydroxy-1-methylethyl)-dihydrofurano]-4,2'-dihydroxychalcone and 3,4-(6",6"-dimethyldihydropyrano)-4',5'-[2''',-(1-hydroxy-1-methylethyl)-dihydrofurano]-2'-hydroxychalcone for which the names bartericins A, B and C, respectively, are proposed. Stipulin, beta-sitosterol and its 3-beta-D-glucopyranosyl derivative were also isolated. The structures of these secondary metabolites were determined on the basis of spectroscopic analysis, especially, NMR spectra in conjunction with 2D experiments, COSY, HMQC and HMBC. The structural relationship of bartericins B and C was further established by the chemical cyclization of one to the other.
Ngameni
Barthelemy
B
Department of Organic Chemistry, University of Yaounde-1, BP 812, Yaounde, Cameroon.
Ngadjui
Bonaventure T
BT
Folefoc
Gabriel N
GN
Watchueng
Jean
J
Abegaz
Berhanu M
BM
D002599:Chalcone / Q000031:analogs & derivatives* / Q000302:isolation & purification; D029586:Moraceae / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D018547:Plant Stems / Q000737:chemistry; D013729:Terpenes / Q000737:chemistry*
D013729:Terpenes; D002599:Chalcone