Using CC(=O)C(=O)OC(C)C, CC(C)OC(=O)C(O)SC(O)C(=O)OC(C)C to produce Cc1c(C(=O)OC(C)C)sc(C(=O)OC(C)C)c1O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.