
%0 Journal Article
%A Johns, SR 
%A Lamberton, JA 
%A Morton, TC 
%A Suares, H 
%A Willing, RI 
%T 22b-[(S)-2-Methylbutanoyloxy]-3-oxoolean-12-en-28-oic acid, a new constituent of <I>Lantana camara</I>
%J Australian Journal of Chemistry
%D 1983/09/01
%V 36
%N 9
%P 1895-1902
%K 
%R https://doi.org/10.1071/CH9831895
%U https://www.publish.csiro.au/paper/CH9831895 
%X 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. 
