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 CC(O)C1C(=O)N2C(C(=O)OCc3ccc([N+](=O)[O-])cc3)=C(SC3CN(c4nc(C(=O)N(CCO[Si](C)(C)C(C)(C)C)C(C)C)cs4)C3)C(C)C12 .
assistant