COc1ccccc1NC(=O)c1cc2c(n(-c3ccc(C)cc3)c1=O)CC(C)(C)CC2=O
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?