[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a 4-oxo monocarboxylic acid that is butyric acid bearing oxo and phenyl substituents at position 4. It has a role as a hapten. It is functionally related to a butyric acid."}, {"from": "gpt", "value": "[C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][C][C][C][=Branch1][C][=O][O]"}]