CCOC(=O)C(/C(=N\NC(=O)OC)C(=O)Nc1cc(OC)ccc1OC)c1cnc2ccccc2n1
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?