78261-83-3 Butanedioic acid, mono(1,2,3,6a,9a,11-hexahydro-4-methoxy-1,11-dioxocyclopenta(c)furo(3',2':4,5)furo(2,3-h)(1)benzopyran-3-yl) ester, (3S-(3alpha,6aalpha,9aalpha))-