COc1cc(-c2cc(NC(C)=O)c3ncc(-c4ccc(C(C)=O)cc4)n3c2)cc(OC)c1OC
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?