Cc1nn(C(=O)c2ccccc2O)c2c1C(c1ccc3ccccc3c1O)SC(=N)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?