A new semisynthetic access to germanicane-type triterpenes was achieved from betulin, a natural triterpene of the lupane family. The Wagner-Meerwein rearrangement of acetylated betulinic acid allowed the formation of the typical ring E of germanicanes and a lactone function. Several germanicane derivatives can be obtained via the lactone ring-opening such as 19 beta-machaerocerol and 19 beta-machaeroceric acid. The cytotoxicity of some compounds was evaluated against two cancerous cell lines. Crown Copyright (c) 2007 Published by Elsevier Ltd. All rights reserved.
Vystrcil et al., Collection of Czechoslovak Chemical Communications, 1959, vol. 24, p. 3279,3284