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
Do retrosynthesis with the product <molecule_2d> .
user
OK. The reactants may be CC1(C)OB(c2ccc(-n3c(CC4CCN(C(=O)C5CC5)C4)n[nH]c3=O)cc2)OC1(C)C.O=C(c1ccccc1)c1cccc(Br)c1 .
assistant