[{"from": "human", "value": "Create a molecule that satisfies the conditions outlined in the description. The molecule is a nitrosamine that has methyl and pentyl substituents. It is a potent oesophageal carcinogen. It has a role as a carcinogenic agent."}, {"from": "gpt", "value": "[C][C][C][C][C][N][Branch1][C][C][N][=O]"}]