[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a monocarboxylic acid that is butyric acid bearing a 2-thienyl group at position 4. It has a role as a hapten. It is a member of thiophenes and a monocarboxylic acid. It is functionally related to a butyric acid."}, {"from": "gpt", "value": "[C][=C][S][C][=Branch1][Ring2][=C][Ring1][Branch1][C][C][C][C][=Branch1][C][=O][O]"}]