[{"from": "human", "value": "Generate a molecule based on this description. The molecule is a 5-oxo-2-furylacetic acid having a 4-methyl substituent. It is a conjugate acid of a 4-carboxylatomethyl-4-methylbut-2-en-1,4-olide(1-)."}, {"from": "gpt", "value": "[C][C][Branch1][#Branch2][C][=C][C][=Branch1][C][=O][O][Ring1][=Branch1][C][C][=Branch1][C][=O][O]"}]