O=C(O)CN(CCNC(=O)OCC1c2ccccc2-c2ccccc21)CCNC(=O)OCC1c2ccccc2-c2ccccc21
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?