COc1cc2c(cc1OC)n(CC(=O)Nc1ccc(C)cc1C)c(=O)n1nc(-c3ccccc3)nc21
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?