O=C(O)CC1OCC=C2CN3CCC45C6=CC(=O)C(O)=C([N+](=O)[O-])C6=NC4C1C2CC35
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?