(S)-Boc-2-carbamoyl-2,3-dihydro-1H-pyrrole is an impurity of Saxagliptin (S143500), which is a potent and selective reversible inhibitor of dipeptidyl peptidase-4, which is being developed for the treatment of type 2 diabetes. It is absorbed rapidly after oral administration and has a pharmacokinetic profile compatible with once daily dosing. Molecular Formula: C10H16N2O3 Molecular Weight: 212.25