COC(=O)C1=C(c2ccc3c(c2)OCO3)O[C@H](c2ccc3c(c2)OCO3)[C@H]1COC(C)=O
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?