C[C@H](NC(=O)CCC(=O)N1C[C@H]2C[C@H](C1)c1cccc(=O)n1C2)c1ccccc1
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?