C=C(C)[C@H]1Cc2c(ccc3c2O[C@H]2COc4cc(OC)c(OC)cc4[C@@H]2C3=O)O1
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?