[{"from": "human", "value": "Generate a molecule based on the given description. The molecule is an alkanesulfonate in which the alkyl group directly linked to the sulfonate functionality is butyl. It is a conjugate base of a butane-1-sulfonic acid."}, {"from": "gpt", "value": "[C][C][C][C][S][=Branch1][C][=O][=Branch1][C][=O][O-1]"}]