COc1cc(NC(=O)C2CC(=O)NC3=C2C(=O)CC(C)(C)C3)c(OC)cc1Cl
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?