O=C(N[C@H](C(=O)O)c1ccccc1)C1CCC(Cn2cnc3ccccc3c2=O)CC1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?