Dinklagins A, B and C: three prenylated flavonoids and other constituents from the twigs of Dorstenia dinklagei

Abstract

Three prenylated flavonoids, dinklagins A, B and C identified, respectively, as (-)-6-(3,3-dimethylallyl)-7-hydroxy-6''', 6'''-dimethylchromeno-(4',3',2''',3''')-flavanone, (+)-5,4',5"xi-trihydroxy-6'',6''-dimethylchromano-(7,6,2'',3'')-flavone and (+)6-(2xi-hydroxy-3-methyl-3-butenyl)-5,7,4'-trihydroxyflavone were isolated from the twigs of Dorstenia dinklagei together with the known 6-prenylapigenin, 4-hydroxylonchocarpin, stipulin and 5,4'-dihydroxy-6'',6''-dimethylchromano-(7,6,2'',3'')-flavone. Their structures were determined on the basis of spectral data and by comparison with data reported in the literature and with authentic specimens for known compounds.