COc1ccc(-n2nc(C(=O)NCC(=O)Nc3cccc(NC(C)=O)c3)c3ccccc3c2=O)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?