COc1cc2c(cc1NC(=O)COC(=O)[C@@H](NS(=O)(=O)c1cccc(Cl)c1)C(C)C)oc1ccccc12
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?