Using CCCSC1=C(C=O)CCc2c1sc1nc3n(c(=O)c21)CCC(C(=O)OCC)CC3 to produce CCCSC1=C(C=O)CCc2c1sc1nc3n(c(=O)c21)CCC(C(=O)OC)CC3, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.