Studies of the optically active compounds of Anacardiaceae exudates. V. Further investigation of the exudate from Campnosperma auriculata Hook. F

Abstract

Distillation of the hydrogenated oil from Campnosperma auriculata Hook. f. yields n-pentacosane-2,6-dione (IV), which is formed from (+)-3-hydroxy-3-nonadecylcyclohexanone (II) by a retro-aldol reaction. In alcoholic alkali, IV is recyclized to 3-nona-decylcyclohex-2-enone (III), and on Wolff-Kishner reduction the disemicarbazone of IV yields n-pentacosane. Oxidation of 3-nonadecylcyclohex-2-enone (III) yields 5-ketotetracosanoic acid, which has been synthesized by an improved method. The synthesis of III and of 3-heptadecylcyclohex-2-enone is described and a convenient method is given for the preparation of 3-methylcyclohex-2-enone. Examination of the mixture of phenols obtained by the action of alkali on C. auriculata oil has shown the presence of 3-nonadecyl phenol and a mixture composed predominantly of cis-monoethylenic C,, alkyl phenols. The phenols are admixed with a small amount of certain long-chain quinols which are also present in the original oils. Nonadecylquinol, one component, has been characterized by conversion into nonadecyl-benzoquinone. The exudate from Campnosperma macrophylla Hook. f. (also Malayan) is unlike that from C. auriculata and contains little oil.