
%0 Journal Article
%A Mc Alpine, JB 
%A Riggs, NV 
%A Gordon, PG 
%T Absolute stereochemistry of calopiptin
%J Australian Journal of Chemistry
%D 1968/08/01
%V 21
%N 8
%P 2095-2106
%K 
%R https://doi.org/10.1071/CH9682095
%U https://www.publish.csiro.au/paper/CH9682095 
%X The &#945;,&#945;?-diaryl-&#946;,&#946;-dimethyltetrahydrofurenoid lignan, calopiptin, from   Piptocalyx moorei has been converted by demethylenation and methylation into veraguensin, now also isolated from Trimenia papuana (both species, family Trimeniaceae). Ozonolysis yields (-)-2,3-dimethylsuocinic acid which establishes the absolute trans configuration of the methyl groups. The benzylic proton giving a signal at low field from the other in the p.m.r, spectrum is assigned as trans to the adjacent methyl group by shielding and spin-decoupling arguments. The signal moves to even lower field on nitration of one of the aryl groups, identified as 3,4-dimethoxyphenyl by competitive nitration experiments and high-resolution mass spectrometry.   Calopiptin is 2R-(3,4-dimethoxyphenyl)-3S,4S-dimethyl-5S-(3,4-methylenedioxyphenyl)tetrahydrofuran. 
