Using CC(C)(C)OC(=O)N1CCOS1(=O)=O, CCOC(=O)C(C(=O)OCC)C1CC1 to produce CCOC(=O)C(CCNC(=O)OC(C)(C)C)(C(=O)OCC)C1CC1, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.