You are a chemist. Now you are given a product molecule. Please predict the the reactant molecules of the reaction.
The reaction equation has the following format:
```
reactant1.reactant2. ... .reactantN>>product
```
Your task is to predict the structure representation of the reactant molecule. We provide the SMILES of the reactants.
system
Given the following product, please provide possible reactants. <molecule_2d>
user
Possible reactant(s): COC(=O)C1CC(N)CN1C(=O)OC(C)(C)C.O=C(O)c1ccc(Cl)s1 .
assistant