COc1ccc(CNC(=O)CN(C(=O)CCC(=O)Nc2ccccn2)c2cccc(C)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?