[{"from": "human", "value": "Generate a molecule based on this description. The molecule is a (2-chloroethy1)nitrosourea derivative related to carmustine, with antineoplastic activity."}, {"from": "gpt", "value": "[C][Branch1][Ring1][C][O][N][C][=Branch1][C][=O][N][Branch1][Ring2][C][C][Cl][N][=O]"}]