COC(=O)c1c(-c2ccc(Br)cc2)csc1NC(=O)Cc1ccc(OC)c(OC)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?