COc1cccc(N2CCN(CC(=O)NC3=Nc4ccccc4N=C(C)C3c3ccccc3)CC2)c1
An acid's negative base-10 logarithmic dissociation constant (pKa) follows directly from its underlying thermodynamics; the negative pKa is directly proportional to its standard Gibbs free energy change. What is the negative pKa value of this molecule?