
TY  - JOUR
A1  - Mc Alpine, JB 
A1  - Riggs, NV 
A1  - Gordon, PG 
T1  - Absolute stereochemistry of calopiptin
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1968
VL  - 21
IS  - 8
SP  - 2095
EP  - 2106
KW  - 
UR  - https://doi.org/10.1071/CH9682095 
N2  - 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. 
ER  -

