COc1ccccc1-c1cc(NC(C)=O)c2ncc(-c3cccc(C(C)=O)c3)n2c1
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?