O=C1CN(C(=O)N[C@@H](Cc2ccccc2)C(=O)N[C@H](Cc2ccccc2)C(=O)O)c2ccccc2N1
Molecules with a polar surface area of greater than 140 angstroms squared (Å2) tend to be poor at permeating cell membranes. What's the psa of this molecule?