COc1cc(/C=C/CNC[C@H]2O[C@@H](n3cc(C)c(=O)[nH]c3=O)C[C@@H]2O)ccc1O
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?