COC(=O)[C@H](Cc1ccc(OC(C)(C)C)cc1)N[C@H](C)C(=O)N[C@@H](Cc1ccccc1)C(=O)OCc1ccccc1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?