[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is a methylguanine in which the methyl group is positioned on the oxygen at position 6. Formed in DNA by alkylation of the oxygen atom of guanine, most often by N-nitroso compounds and sometimes due to methylation by other compounds such as endogenous S-adenosylmethionine, it base-pairs to thymine rather than cytidine, causing a G:C to A:T transition in DNA. It has a role as a mutagen."}, {"from": "gpt", "value": "[C][O][C][=N][C][=Branch1][O][=N][C][=C][Ring1][=Branch1][N][C][=N][Ring1][Branch1][N]"}]