2-(2,5-diketo-3-furyl)acetic acid 2-(2,5-dioxofuran-3-yl)acetic acid 2-(2,5-dioxofuran-3-yl)ethanoic acid cis-Aconitic anhydride,cis-Propene-1,2,3-tricarboxylic anhydride cis-Prop-1-ene-1,2,3-tricarboxylic acid anhydride, (2,5-Dihydro-2,5-dioxofur-3-yl)acetic acid 2-(2,5-dioxo-2,5-dihydrofuran-3-yl)acetic acid (2,5-Dihydro-2,5-dioxofur-3-yl)acetic acid 3-(Carboxymethyl)-2,5-dihydro-2,5-dioxofuran, cis-Aconitic anhydride , cis-Prop-1-ene-1,2,3-tricarboxylic anhydride