CCOC(=O)Nc1cc2c(c(N)n1)N=C(c1ccccc1)[C@H](C)N2.O=S(=O)(O)CCO
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?