[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a butan-4-olide having a 2-chloroethyl group at the 3-position and two methyl substituents at the 5-position. It is an organochlorine compound and a butan-4-olide."}, {"from": "gpt", "value": "[C][C][Branch1][#C][C][C][Branch1][Branch2][C][=Branch1][C][=O][O][Ring1][=Branch1][C][C][Cl][C]"}]