Synonyms: 19-Nor-1,2-secoergost-9(11)-en-2-oicacid, 6,7-epoxy-22,24,25-[ethylidynetris(oxy)]-5-hydroxy-12-oxo-, g-lactone, [5a,6a,7a,10b,22R(S)]-; (+)-Petuniolide C;Petuniolide C;Spiro[2H-cyclopenta[7,8]naphth[1,2-b]oxirene-2,2'(5'H)-furan]-5,5'(3H)-dione,1a,3',4',5a,6,7,8,8a,8b,8c-decahydro-3,5a-dimethyl-6-[1-(1,5,6,6-tetramethyl-2,7,8-trioxabicyclo[3.2.1]oct-3-yl)ethyl]-,[1aS-[1aa,2b,3a,5aa,6a[R*(1R*,3S*,5S*)],8ab,8ba,8ca]]-