CC1=C(C(N)=O)C(c2ccc3c(c2)OCO3)n2nc(-c3cccc(C)c3)nc2N1
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?