You are a chemist. Now you are given a description of a molecule. Please generate a molecule that meets the description.
system
I need a molecule that meets the following conditions: The molecule is a pde4 inhibitor. Please represent the molecule in SMILES.
user
CC1CN(C(=O)OC(C)(C)C)CCN1c1nc2cc(Cl)cc(-c3ncc(C#N)s3)c2o1
assistant