[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is a butan-4-olide and a hydroxy carboxylic acid. It has a role as a metabolite."}, {"from": "gpt", "value": "[C][C][=Branch1][C][=O][O][C@@H1][Branch1][N][C@@][Ring1][=Branch1][Branch1][=Branch1][C][=Branch1][C][=O][O][O][C][=Branch1][C][=O][O]"}]