COc1cc2c(cc1OC)[C@@H]1C(=O)c3ccc4oc(C(C)C)cc4c3OC1CO2
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?