COc1ccc2c(c1)C1NC(S)=NC(C)(O2)C1C(=O)Nc1ccc(C)cc1C
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?