[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is a ketoaldonic acid that is butyric acid carrying an oxo substituent at position 3 as well as two hydroxy substituents at positions 2 and 4 (the S-enantiomer). It is a ketoaldonic acid, a dihydroxy monocarboxylic acid and a 3-oxo monocarboxylic acid. It is functionally related to a butyric acid. It is a conjugate acid of a (S)-2,4-dihydroxy-3-oxobutanoate. It is an enantiomer of a (R)-2,4-dihydroxy-3-oxobutanoic acid."}, {"from": "gpt", "value": "[C][Branch1][=C][C][=Branch1][C][=O][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][O][O]"}]