You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
Suppose there is a molecule that meets the following description: The molecule is a proteasome inhibitor. Please write the SMILES representation of it.
user
COCC(NC(=O)c1cnc(C)s1)C(=O)NC(COC)C(=O)OC
assistant