[{"from": "human", "value": "Describe this molecule. [C][C][=C][C][C][=Branch1][C][=O][O][Ring1][=Branch1]"}, {"from": "gpt", "value": "The molecule is an angelica lactone and a butenolide. It is functionally related to a but-3-en-4-olide. It is a tautomer of a beta-angelica lactone."}]