COc1ccc(NC(=O)c2c(C)oc3ccc(O)c(CN4CCN(C)CC4)c23)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?