COc1ccc(S(=O)(=O)Nc2cccc3c2O[C@H](CN(C)S(=O)(=O)c2cccs2)[C@@H](C)CN([C@H](C)CO)C3=O)cc1
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?