Aromaticine, a Sesquiterpene Lactone from Amblyopappus Pusillus

AROMATICINE (SYSTEMATIC NAME: 4a,8-dimethyl-3-methyl-ene-3,3a,4,4a,7a,8,9,9a-octa-hydro-azuleno[6,5-b]furan-2,5-dione), C(15)H(18)O(3), is a natural lactone isolated from Amblyopappus pusillus. The mol-ecular structure and conformation agree with the results of Romo, Joseph-Nathan & Díaz [(1964 ▶). Tetra-hedron, 20, 79-85]. The fused-ring system contains a seven-membered ring in a twist-boat conformation and two five-membered rings trans fused in envelope conformations.