Polycyclic Systems. Part XI. A Synthesis of 4'-(1,2-Dirmethyl-propyl)-6'-methylindeno-(2',3'-1,2) phenanthrene

The synthesis of 4'-(1.2-dimethylpropyl)-6'-methylindeno-(2',3'-1.2)phenanthrene, a supposed dehy­drogenation product of ergosterol, is described. The synthetic hydrocarbon is found to be different from that derived from ergosterol. This and a similar observation regarding the dehydrogenation product of cholesterol, published earlier., clearly show the inadequacy of Bergmann's mechanism of the formation of indenophenan threne derivatives from the steroids.