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
<molecule_2d> Given the product provided, propose some possible reactants that could have been employed in its formation.
user
Here are possible reactants: Cn1nc(-c2cnc3c(n2)c(C(=O)NC(C(=O)N2CCC(C#N)CC2)C2CC2)cn3COCC[Si](C)(C)C)c2cc(Cl)c(Cl)cc21 .
assistant