The structure of 19αH-Lupeol methyl ether from Chionochloa bromoides

Abstract

The structure of l9αH-lupeol methyl ether isolated from Chionochloa bromoides has been determined by ¹³C n.m.r. spectroscopy and X-ray diffraction. Crystals of the triterpene are monoclinic, space group P2₁, with a 8.071(1), b 14.5477(6), c 11.6061(4) Å, β 104.466(5)º, V 319.6 ų and Z 2. The structure was solved by direct methods, and was refined to R 0.054 for 1092 observed reflections. Previous reports of synthetic and naturally occurring 19αH-lupanes are briefly discussed, as is the distribution of the chemotaxonomically discriminating triterpene methyl ethers in Chionochloa.