TERPENOID CHEMISTRY .15. 1,5-DIMETHYLCYCLODECA-1,5,7-TRIENE PRECURSOR OF GEIJERENE IN GEIJERA PARVIFLORA (LINDLEY)

Geijera parviflora leaves which yield geijerene when worked up under the usual conditions of steam-distillation and fractional distillation have been found to contain a new hydrocarbon, Cl2H18 (pregeijerene), and only a trace of geijerene. The structure of pregeijerene has been shown by degradative and spectral examination to be 1, 5-dimethylcyclodeca-1, 5, 7-triene, the disubstituted double bond having a cis configuration. The hydrocarbon forms a crystalline adduct with silver nitrate and rearranges thermally to yield geijerene. © 1968 CSIRO. All rights reserved.