You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
I give you a description of a molecule, and you need to return one molecule in SMILES that meets the description. The description: It belongs to the pain treatment class of molecules.
user
O=c1oc(Cn2ncc3[nH]cnc3c2=O)nn1CCc1ccc(Cl)cc1
assistant