COC(=O)c1cc(NC(=O)c2cc(NC(=O)Cc3c[nH]c4ccccc34)cn2C)cn1C
The negative base-10 logarithmic of dissociation constant (pka) for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the pKa value is directly proportional to the standard Gibbs free energy change for the reaction. What is the pka value of this molecule?