C=C(C)CNC1=C(C(N)=O)C(=N)C(C(=O)Nc2sc3c(c2C(=O)OC)CCC3)S1
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?