THE STRUCTURE OF A NEW NATURAL APOTIRUCALLANE-TYPE TRITERPENE AND THE STEREOCHEMISTRY OF THE RELATED TERPENES. X-RAY AND 13C NMR SPECTRAL ANALYSES

Abstract The structure of a new apotirucallane-type triterpene, 21-O-acetyl toosendantriol, isolated from the fruit of Melia toosendan was determined by X-ray analysis. Based on comparison of the 13C chemical shifts, the steric structures of the side chains of two epimeric 21-acetates derived from a tirucallane-type terpene, melianone were also clarified.