[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is a butenolide."}, {"from": "gpt", "value": "[C][=C][Branch1][#C][C][=Branch1][C][=O][O][/C][\\-Ring1][=Branch1][=C][/C][=Branch1][C][=O][O][Cl]"}]