Sitagliptin Impurity E

Sitagliptin S-Isomer HCl; (S)-3-amino-1-(3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)-4-(2,4,5-trifluorophenyl)butan-1-one hydrochloride;