Using CCOCC, Clc1cc2c(cc1Cn1c(Br)nc(Br)c1Br)OCO2 to produce O=Cc1nc(Br)c(Br)n1Cc1cc2c(cc1Cl)OCO2, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.