Terpenoids of the volatile oil of Bursera graveolens

In the course of studies on the constituents of the woody material of Bursera graveolens, the aroma components that provide its characteristic spicy, sweet and balsamic odor were investigated using GC/MS. Five compounds, 1-5, were isolated from the volatile oil obtained by diethyl ether extraction of B. graveolens wood chips, and their structures were elucidated by means of NMR studies. Their structures were determined as (-)-dihydro-α-agarofuran (1), (-)-5,11-epoxy-4α,5β,10α-eudesm-1-ene (2), (-)-4α-hydroxydihydroagarofuran (3), (-)-3β,4β-oxidoagarofuran (4) and (-)-10-epi-γ-eudesmol (5). Of these, (-)-5,11-epoxy-4α,5β-10α-eudesm-1-ene (2) is a new sesquiterpenoid that has not previously been reported in literature, and the presence of (-)-dihydro-α-agarofuran (1), (-)-4a-hydroxydihydroagarofuran (3), (-)-3β,4β-oxidoagarofuran (4) and (-)-10-epi-γ-eudesmol (5) in B. graveolens is reported for the first time.