[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is a hydroxy fatty acid anion that is the conjugate base of 2-hydroxybutyric acid, obtained by deprotonation of the carboxy group. It has a role as a human metabolite. It is functionally related to a butyrate. It is a conjugate base of a 2-hydroxybutyric acid."}, {"from": "gpt", "value": "[C][C][C][Branch1][=Branch1][C][=Branch1][C][=O][O-1][O]"}]