COc1c(CC(=O)c2cc3c(cc2O)OC(C)(C)C(O)C3)ccc2c1C=CC(C)(C)O2
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?