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): CCOC(=O)C12CC1C=CCCCCN(C)C(=O)C1CC(Oc3cc(-c4csc(NC(C)C)n4)nc4cc(OC)ccc34)CC1C(=O)N2 .
assistant