[Constituents of Aristolochia triangularis].

The roots and stems of Aristolochia triangularis Chamisso, a woody climber growing in Brasil, contain fatty acids as well as (-)-kaur-16-en-18-acid, but no aristolochic acids. The following stigmastane type triterpenes have been isolated: stigmast-4-en-3-on, stigmastan-3,6-dion and stigmast -4-en-3,6-dion as well as kaurane diterpenes: (-)-kaur-16-en, (-), kaur-16-en-18-al, (-)-kauran-16alpha-ol-18-al, (-)-16alpha, 17-epoxykauran, (-)-kaur- 16 - en-18-ol and (-)-kaur-15-en-17-ol. In addition sesquiterpenes have been found: (-)-alpha-ylangen, (-)-alpha-copaen, (E)-beta-elemen, gamma-elemen, (E)-(R)-Nerolidol. The lignanes isolated from A. TRIANGULARIS include cubebin, found so far only in Piper cubeba, and galbacin. The new lignans 3,4-dimethoxy-3,4-desmethylendioxycubebin and 3',4'-dimethoxy-3',4'-desmethylendioxycubebin have been identified. For better interpretation of the (1)H-NMR-spectra in relation to the stereochemistry, the 6,6'-dinitro derivates are suitable.