[{"from": "human", "value": "Generate a molecule based on this description. The molecule is a 2-oxo monocarboxylic acid that is 2-oxobutanoic acid with double bond at position 3. It has a role as a metabolite. It is a 2-oxo monocarboxylic acid and an enone."}, {"from": "gpt", "value": "[C][=C][C][=Branch1][C][=O][C][=Branch1][C][=O][O]"}]