Rapid and simple isolation of zingiberene from ginger essential Oil

A sesquiterpene-enriched fraction of ginger oil was treated with the dienophile 4-phenyl-1,2,4-triazoline-3,5-dione (2), which selectively formed a Diels-Alder adduct with the sesquiterpene hydrocarbon zingiberene (1). The adduct was purified by flash chromatography, then hydrolyzed to return zingiberene in good yield and >99% purity.