Using O=C(O)c1cc2ccccc2c(-c2c(O)c(C(=O)O)cc3ccccc23)c1O to produce Oc1ccc2ccccc2c1-c1cccc2ccccc12, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.