Studies on Isoprenoide. I

On Longifolane

Abstract

The double bond in longifolene resists hydrogenation at ordinary temperature and pressure, using sodium and ethanol, nickel, or palladium as a catalyst. The reduction, however, is easily effected at ordinary temperature and pressure when acetic acid is used as a solvent and platinum as a catalyst, hydrogen being absorbed quantitatively within a short period. Longifolane, the hydrogenation product, is an oily substance similar to longifolene. Its oxidation with chromium trioxide in acetic acid solution, as in the case of longifolene, afforded a small amount of isolongifolic acid and a large amount of a diketone, m. p. 156-157°, as the oxidation products but not longif ofl-1, 2-dione, which is obtained by the oxidation of longif olene. Dehydrogenation of longifolane with selenium also met with strong resistance but an extremely minute amount of cadalene was formed.