[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is an acetate ester that is butyl acetate substituted by an oxo group at position 3. It has a role as a metabolite. It is functionally related to a butyl acetate."}, {"from": "gpt", "value": "[C][C][=Branch1][C][=O][C][C][O][C][=Branch1][C][=O][C]"}]