[{"from": "human", "value": "Use the given information to create a molecule that fulfills the desired purpose. The molecule is a 2-oxo monocarboxylic acid anion. It is functionally related to a valerate. It is a conjugate base of an acetylpyruvic acid."}, {"from": "gpt", "value": "[C][C][=Branch1][C][=O][C][C][=Branch1][C][=O][C][=Branch1][C][=O][O-1]"}]