
TY  - JOUR
A1  - Johns, SR 
A1  - Lamberton, JA 
A1  - Morton, TC 
A1  - Suares, H 
A1  - Willing, RI 
T1  - 22b-[(S)-2-Methylbutanoyloxy]-3-oxoolean-12-en-28-oic acid, a new constituent of <I>Lantana camara</I>
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1983
VL  - 36
IS  - 9
SP  - 1895
EP  - 1902
KW  - 
UR  - https://doi.org/10.1071/CH9831895 
N2  - 22&#946;-[(S)-2-Methylbutanoyloxy]-3-oxoolean-12-en-28-oic acid, a new constituent of Lantanu camara L. is closely related to lantadene A and lantadene B. Although hydrolysis gives 2-methylbutanoic acid as a partial racemate, it has been shown by n.m.r. spectroscopy that the natural ester is theoptically pure (S)-isomer. Catalytic hydrogenation of lantadene A gives a mixture of diastereoisomeric esters in which the (S)-2-methylbutanoate predominates, and a 1 : 1 mixture of the (R)- and(S)-esters was obtained by esterification with (RS)-2-methylbutanoyl chloride of 22&#946;-hydroxy-3-oxoolean-12-en-28-oic acid protected as the diphenylmethyl ester. 
ER  -

