CC(=O)Nc1ccc(-c2cc(-c3ccc(NC(C)=O)cc3)nc(-c3ccccc3)n2)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?