Structures of α- and β-turmerone

Abstract

Procedures are described for isolating turmerones from Curcuma longa rhizomes and for chromatographically separating α- from β-turmerone. Using a combination of spectroscopic techniques (especially high field ¹H NMR spectroscopy and chiroptical methods) these compounds are shown to be (1′R, 6S)-2-methyl-6-(4-methylcyclohexa-2,4-dienyl)hept-2-en-4-one 2(α-turmerone) and (1′R, 6S)-2-methyl-6-(4-methylenecyclohex-2-enyl)hept-2-en-4-one 3(β-turmerone).