COc1cc(NS(=O)(=O)c2ccc(NS(=O)(=O)c3ccc(NC(C)=O)cc3)cc2)nc(OC)n1
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?