COc1ccc(/C=N/Nc2nc(-c3cc4oc(=O)n(C)c4cc3Cl)cs2)cc1OC
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?