Sesquiterpenes from lippia integrifolia essential Oil

Four sesquiterpenes (1-4) with the africanane skeleton [of which only 5-africanene (1) has been previously reported] and the new asteriscane derivative asterisca-3(15),6-diene (5) were isolated from the essential oil of Lippia integrifolia. A further new compound, african-2(6)-ene (7), was obtained as a semisynthetic product by derivatization of isoafricanol (6). The structures of the new compounds were assigned on the basis of spectroscopic data, enantioselective gas chromatography, and by chemical correlations.