COc1cc(OC)cc(C(=O)NC(C(=O)Nc2ccc3c(c2)OCO3)C(C)C)c1
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?