COc1ccc(OC)c(CCNC(=O)c2sc3nc4n(c(=O)c3c2C)CCCC4)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?