COc1ccc([N+](=O)[O-])cc1N(CC(O)CN1C(=O)NC(C)(C)C1=O)S(=O)(=O)c1ccccc1
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?