Using Fc1cncc(Br)c1, c1cnc(-c2cccc(-c3nccs3)n2)nc1 to produce Fc1cncc(-c2cnc(-c3cccc(-c4ncccn4)n3)s2)c1, please predict the solvent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.