COc1ccc(OC)c(-n2c(=S)[nH]c3cc(C(=O)N4CCC(C(N)=O)CC4)ccc3c2=O)c1
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?