CCOc1ccc(NC(=O)CN(C)C(=O)c2ccccc2SCC(=O)N2CCCC2)cc1OCC
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?