Using Cc1nc(Cl)c2c(n1)CN=C(c1ccccc1)c1cc(Cl)ccc1-2, CO to produce COc1nc(C)nc2c1-c1ccc(Cl)cc1C(c1ccccc1)=NC2, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.