[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is an organosulfate oxoanion that is the conjugate base of methyl sulfate; major species at pH 7.3. It is a conjugate base of a methyl sulfate."}, {"from": "gpt", "value": "[C][O][S][=Branch1][C][=O][=Branch1][C][=O][O-1]"}]