You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
Could you please return a molecule that adheres to this description? The molecule is a proteasome inhibitor.
user
CC(C)CC(NC(=O)C(CCc1ccccc1)NC(=O)OC(C)(C)C)C(=O)NC(Cc1ccccc1)C(=O)O
assistant