ethyl 2-(2-(chlorocarbonyl)benzoyl)-3,3-diethoxyacrylate

3-oxo-2-(3-oxo-3H-isobenzofuran-1-ylidene)-butyric acid ethyl ester

ethyl 1,3-dioxoindene-2-carboxylate

(3E)-3-(3-oxo-2-benzofuran-1-ylidene)-2-benzofuran-1-one

(Z)-[1,1']biisobenzofuranylidene-3,3'-dione