COc1cccc(NC(=O)CSC2=Nc3ccccc3C3=NC(CC(=O)NCc4ccc5c(c4)OCO5)C(=O)N23)c1
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?