(E)-4-(1,3-Benzodioxol-5-yl)-4-oxo-2-butenoic acid (E)-4-(3,4-Methylenedioxyphenyl)-4-oxo-2-butenoique acide [French] 2-Butenoic acid, 4-(1,3-benzodioxol-5-yl)-4-oxo-, (E)- 84609-13-2