[{"from": "human", "value": "Could you provide a description of this molecule? [C][C][Branch1][#Branch2][C][=C][C][=Branch1][C][=O][O][Ring1][=Branch1][C][C][=Branch1][C][=O][O-1]"}, {"from": "gpt", "value": "The molecule is the conjugate base of 4-carboxymethyl-4-methylbut-2-en-1,4-olide; major species at pH 7.3. It is a conjugate base of a 4-carboxymethyl-4-methylbut-2-en-1,4-olide."}]