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 O=C(O)c1ccc2[nH]cnc2c1.c1cc2c(cc1CC1CCCCC1)CCC1NCCCC21 .
assistant