Using COc1cc2c(cc1OC)C(N(CC(=O)O)C(=O)C(CS)CS)CC2 to produce COc1cc2c(cc1OC)C(N(CC(=O)O)C(=O)C1CSSC1)CC2, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.