[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is an alpha-bromoketone that is acetone in which one of the hydrogens is replaced by a bromine atom. A poweful lachrymator, it was formerly used as a chemical weapon. It has a role as a lachrymator. It is functionally related to an acetone."}, {"from": "gpt", "value": "[C][C][=Branch1][C][=O][C][Br]"}]