G.H. Constantine

Revised structure of a steroid oxide from Rhododendron macrophyllum

Abstract Updated NMR evidence is given that a previously reported triterpenoid oxide is not D:B Friedoolean-3,5-oxide, but is, instead, D:B-Friedoolean-3,10-oxide. A mechanistic explanation is given as to why the chemical evidence does not seem to support the NMR data.

D:B-friedoolean-3,5-oxide in Rhododendron macrophyllum

Abstract The triterpenoid epoxide present in the title plant has been isolated previously from species of Dendropanax and other Rhododendrons and given different names, i.e. epoxyglutinane, dendropanoxide, and possibly campanulin. Previously conflicting evidence regarding the position of the epoxide group and the nomenclature of the compound have now been clarified.

Root triterpenes of Vaccinium species

Abstract The underground portions of Vaccinium membranaceum (Dougl.) and V. parvifolium (Sm.) were examined for their triterpene content. The first-mentioned ericaceous plant yielded taraxerol, taraxerone, β-sitosterol, and friedel-3-ene. All but the last compound were detected in the other species. This is the first report of friedel-3-ene in the Ericaceae.