[{"from": "human", "value": "Generate a molecule based on this description. The molecule is a ketoaldehyde that is octanal carrying an acetyl substituent at position 3 (the S-enantiomer)."}, {"from": "gpt", "value": "[C][C][C][C][C][C@@H1][Branch1][Ring2][C][C][=O][C][=Branch1][C][=O][C]"}]