COCCN1C(=O)/C(=C/c2ccc(OCc3ccc(C(=O)O)cc3)c(OC)c2)S/C1=N\c1ccccc1
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?