COc1ccc2c3c1O[C@H]1C(O)CCC4(O)[C@@H](C2)NCC[C@]314
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 negative pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the negative pKa value of this molecule?