Pernambucone, a new tropone derivative from Croton argyroglossum.

Two tropone derivatives, orobanone (1), previously isolated from Orobanche rapum-genistae, and the new natural product pernambucone (3,8-dimethyl-5-isopropyl-2,3-dihydro-1H-azulene-1,6-dione, 2), were isolated from the sterm bark of Croton argyroglossum. The structures were elucidated from spectroscopic data.