[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is an optically active form of 2-hydroxybutyric acid having (S)-configuration. It is a 2-hydroxybutyric acid and a (2S)-2-hydroxy monocarboxylic acid. It is a conjugate acid of a (S)-2-hydroxybutyrate. It is an enantiomer of a (R)-2-hydroxybutyric acid."}, {"from": "gpt", "value": "[C][C][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][O]"}]