[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is a dieter obtained by the formal condensation of fumaric acid with ethanol. It has a role as a metabolite. It is functionally related to a fumaric acid."}, {"from": "gpt", "value": "[C][C][O][C][=Branch1][C][=O][/C][=C][/C][=Branch1][C][=O][O][C][C]"}]