A novel sesquiterpene peroxide from Alpinia japonica (Thunb.) MIQ.

A novel sesquiterpene peroxide, hanalpinol (1a), has been isolated from the rhizomes of Alpinia japonica. Oxidation of 1a with pyridinium chlorochromate gave a crystalline, α, β-unsaturated ketone (2), whose structure was established by means of X-ray analysis. The IR spectrum of 1a revealed the presence of intramolecular hydrogen bonding, and acid treatment of 1a resulted in the formation of furopelargone B (4), which was present naturally in...