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(B2OC(C)(C)C(C)(C)O2)OC1(C)C.CNC(=O)c1c(C2CC2)oc2cc(N(C)S(C)(=O)=O)c(Br)cc12 .
assistant