CCCSc1nc2c(c(=O)[nH]1)C(c1ccc(O)c(OCC)c1)CC(=O)N2
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?