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 COCC1OC(n2cnc3c(NCC(c4ccccc4)c4ccccc4)nc(CCN)nc32)C(O[Si](C)(C)C(C)(C)C)C1O[Si](C)(C)C(C)(C)C.O=CC1CC1 .
assistant