O=C(CCC1CCCCC1)NCCN1C2=NC[C@H](Cc3ccc(O)cc3)N2C[C@H]1Cc1ccc(O)cc1
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?