Euphane group

Triterpenoids are a major group of natural products in higher plants. The tetracyclic triterpenoids, based on the lanostane, euphane, onocer-ane, and dammarane skeletons, are found mostly in vascular plants and... 

The interesting biological properties shown by many saponins, coupled with improvements in spectroscopic methods of structure determination have led to the increased study of this class of compound. The following papers deal with saponins and prosapogenins which are based on known triterpenoids of the following groups dammarane-euphane,158 lupane,159 oleanane,160 and ursane.161... 

Sapelin A (69) and sapelin B (70) have been obtained" from Entandrophragma cylindricum (Meliaceae) and are further examples of the group of euphane or tirucallane derivatives which co-occur with, and are likely precursors of, tetranor-triterpenoids (see later). Sapelin A was readily correlated with bourjotinolone A (71 ). Sapelin B reacted with sodium periodate to give the dialdehyde (72) which was transformed successively by sodium amalgam and chromium trioxide into the y-lactone (73) previously obtained from sapelin A and bourjotinolone A. 

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