COc1cc2c(cc1O)[C@@H]1Cc3c(cc(OC)c(OC)c3Oc3cc4c(cc3OC)CCN(C)[C@@H]4Cc3ccc(O)cc3)[C@H](C2)N1C
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?