Revised structures of cangorosins, triterpene dimers from Maytenus ilicifolia

Structures of four triterpene dimers, cangorosins, isolated from Maytenus ilicifolia Mart., were previously reported to consist of two triterpene units joined by an ether bond formed between the two A rings. On the basis of detailed studies of their chemical and spectroscopic data, including inverse-detected BD-NMR data, and comparisons with other known triterpene dimers, the structures of the cangorosins have been revised to triterpene dimers linked by two ether bridges between the two A rings for cangorosin B and between the A and the B rings for the cangorosin A series (cangorosin A, isocangorosin A, and 6',7'-dihydroisocangorosin A).