[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is a C4-dicarboxylate resuting from deprotonation of both carboxy groups of dihydroxyfumaric acid. It is functionally related to a fumarate(2-). It is a conjugate base of a dihydroxyfumaric acid."}, {"from": "gpt", "value": "[C][=Branch1][#Branch2][=C][Branch1][=Branch1][/C][=Branch1][C][=O][O][\\O-1][Branch1][=Branch1][\\C][=Branch1][C][=O][O][/O-1]"}]