COc1cc(C2Nc3ccc4ccccc4c3C3=C2C(=O)CC(C)(C)C3)ccc1OCC(=O)O
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?