[{"from": "human", "value": "Describe this molecule. [C][C@H1][Branch1][#Branch2][C][N][C][C][O][C][C][Ring1][=Branch1][C][Branch1][=Branch2][C][=C][C][=C][C][=C][Ring1][=Branch1][Branch1][=Branch2][C][=C][C][=C][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][N][C][C][C][C][Ring1][Branch1]"}, {"from": "gpt", "value": "An opioid analgesic structurally related to methadone and used in the treatment of severe pain. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1070)"}]