Using CSc1ncc2c(n1)-c1cc(C(=O)OC(C)(C)C)sc1CC2 to produce CSc1ncc2ccc3sc(C(=O)OC(C)(C)C)cc3c2n1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.