ethyl 7-N-(carbethoxy)aminocoumarin-4-acetate

ethyl 2-(2,4-dioxo-1,3-oxazin-6-yl)acetate

diethyl 4-(2-ethoxy-2-oxoethyl)-2,6-dihydroxybenzene-1,3-dicarboxylate

diethyl 4-carboxy-3,5-dihydroxyhomophthalate

3-(Ethoxycarbonyl)-1-methylpyrrole-2-acetic acid