COc1ccc(S(=O)(=O)Nc2cc3c4c(oc3c3ccccc23)CC(C)(C)CC4=O)cc1
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?