COc1cc(NC(=O)COc2cc(C)cc3oc(=O)c(C)c(C)c23)cc(OC)c1OC
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?