Hillyl acetate, ,8-hexamethyl-5-oxo-5,6,7,8-tetrahydro-2H-chromen, has
been isolated from the steam volatile leaf oil of Syncarpia hillii an
d its molecular structure was determined by X-ray crystallography. Thi
s crystalline compound accounts for 60-80% of the oil. The remainder o
f the oil comprised a suspected related diketone and over 50 mono- and
sesquiterpenes