COc1cc(/C=C/C(=N\NC(=S)NN)c2sc(NNC(C)=O)nc2C)ccc1O
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?