[{"from": "human", "value": "Given this chemical reaction, what are some reagents that could have been used? [C][C][O][C][=Branch1][C][=O][C][C][#N].[N][C][C][O]>>[N][#C][C][C][=Branch1][C][=O][N][C][C][O]"}, {"from": "gpt", "value": "[C][C][O]"}]