[{"from": "human", "value": "Use the given information to create a molecule that fulfills the desired purpose. The molecule is an agent that reacts with guanine to create a covalent adduct. In vivo, Kethoxal reacts with 30S ribosomal subunits yielding inactive ribosomes."}, {"from": "gpt", "value": "[C][C][O][C][Branch1][C][C][C][=Branch1][C][=O][C][Branch1][C][O][O]"}]