[{"from": "human", "value": "What can you tell me about this molecule? [C][C][C][=Branch1][C][=O][N][Branch1][=Branch2][C][=C][C][=C][C][=C][Ring1][=Branch1][C][Branch2][Ring1][Ring2][C][C][N][Branch1][Branch1][C][C][Ring1][=Branch1][C][C][C][=C][C][=C][C][=C][Ring1][=Branch1][C][=C][C][=C][C][=C][Ring1][=Branch1]"}, {"from": "gpt", "value": "The molecule is a sythetic opioid derived from fentanyl. 4-Phenylfentanyl is around 8x the potency of fentanyl in analgesic tests on animals, but more complex 4-heteroaryl derivatives such as substituted thiophenes and thiazoles are more potent still, as they are closer bioisosteres to the 4-carbomethoxy group of carfentanil."}]