(2,4-dihydroxyphenyl)-(2,5-dihydroxyphenyl)methanone

(4-acetyloxy-3-carbonochloridoylphenyl) acetate

methyl 3,6-dioxocyclohexa-1,4-diene-1-carboxylate

2-(2-carboxy-3,6-dioxocyclohexa-1,4-dienylamino)benzoic acid

2-({4-[(2-carboxyphenyl)amino]-2-carboxy-3,6-dioxocyclohexa-1,4-dienyl}amino)benzoic acid