[{"from": "human", "value": "Generate a molecule based on the given description. The molecule is a hydroxy fatty acid anion that is the conjugate base of 2-(hydroxymethyl)butanoic acid. It has a role as a human metabolite. It is a conjugate base of a 2-ethylhydracrylic acid."}, {"from": "gpt", "value": "[C][C][C][Branch1][Ring1][C][O][C][=Branch1][C][=O][O-1]"}]