Long-chain phenols. Part III. Identification of the components of a novel phenolic fraction in anacardium occidentale(cashew nut-shell liquid) and synthesis of the saturated member

Abstract

A hitherto undetected phenolic fraction in Anacardium occidentale(in the nut-shell liquid and not in the edible kernel) has been shown spectroscopically and chromatographically to comprise the saturated phenol 2-methyl-5-pentadecylresorcinol, its 2-methyl-5-[(8Z)-pentadec-8-enyl], 2-methyl-5-[(8Z,11Z)-pentadeca-8,11-dienyl], and 2-methyl-5-[(8Z,11Z)-pentadeca-8,11,14-trienyl] analogues, and small amounts of C₁₇ components. The unsaturated members are converted by hydrogenation of the side-chain into the saturated phenol, which has been synthesised. The 4-methyl analogue is absent and occurrence of the novel phenol is an instance of specific C-methylation. We report C-demethylation and isomer formation during the syntheses of the 2- and the 4-methyl saturated phenols.