COc1ccc(CCNC(=O)CCCCCn2c(=O)[nH]c3cc(OC)c(OC)cc3c2=O)cc1OC
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?