COC(=O)c1cc(NC(=O)Cn2ncc3c([nH]c4ccccc43)c2=O)cc(C(=O)OC)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?