COc1ccc(OC)c(NC(=O)Cn2c(=O)cc(-c3ccccc3)c3c(C)nn(C)c32)c1
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?