COc1ccc2c(c1)cc(C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@@H](C)C(=O)O)n2C
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?