COC(=O)C1OC(=O)C2OC23[C@@]1(C)CCC1[C@@]3(C)C(O)CC2C(C)(C)C(OC(C)=O)CC(OC(C)=O)[C@]21C
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?