[(4,5-dioxocyclohepta-2,6-dien-1-ylidene)amino] acetate

原儿茶酸

2,5-二氨基环庚-2,4,6-三烯-1-酮

5-溴-2-羟基环庚烷-2,4,6-三烯-1-酮

2-羟基-5-氨基-2,4,6-环庚三烯-1-酮