Study of the Essential Oil of Wild Perilla and the Stereospecific Reduction of (−)‐Piperitone

Abstract

AbstractThe essential oil from wild perilla contains 55% (−)‐piperitone, 31% (−)‐limonene, 6% α‐caryophyllene, and 0.5% (−)‐piperityl formate. 2,4‐Dinitrophenylhydrazone was found to be the most suitable derivative for the identification of piperitone. Partial racemization, that occurred during the formation of the semicarbazone and also during the hydrolysis of the semicarbazone, was confirmed by the isolation of a new optically active semicarbazone of (−)‐piperitone. Reduction of (−)‐piperitone with sodium and moist ether gave (+)‐isomenthol in high yield. This will find application in stereospecific synthesis.