COC(=O)[C@@H]1C[C@H]2[C@H](c3ccccc3Br)[C@@H](OC(C)=O)[C@@H](OCc3ccccc3)ON2O1
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?