COc1ccc(C2=NN(C(=O)CCC(=O)O)C(c3ccc(OC)c(OC)c3)C2)cc1
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?