COc1ccc(S(=O)(=O)Nc2cccc3c2O[C@@H](CN(C)Cc2ccc(C(=O)O)cc2)[C@@H](C)CN([C@H](C)CO)C3=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?