COC(=O)c1ccccc1NC(=O)Cn1c(=O)cc(C)c2c(C)nn(-c3cccc(Cl)c3C)c21
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?