COc1ccc(C2=NOC(Cn3nc(C(=O)NCc4ccco4)cc3-c3ccccc3)C2)cc1
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?