Using CCOC(=O)N(CCc1cc2cc(Br)cc(Cl)c2o1)CC(OC)OC to produce CCOC(=O)N1C=Cc2c(oc3c(Cl)cc(Br)cc23)CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.