Sitagliptin phosphate monohydrate654671-77-9100 % similar Sitagliptin phosphate654671-78-095 % similar Sitagliptin486460-32-683 % similar 1-[5,6-Dihydro-3-(trifluoromethyl)-1,2,4-triazolo[4,3-A]pyrazin-7(8H)-yl]-4-(2,4,5-trifluorophenyl)-1,3-butanedione764667-65-458 % similar (2Z)-3-Amino-1-[5,6-dihydro-3-(trifluoromethyl)-1,2,4-triazolo[4,3-A]pyrazin-7(8H)-yl]-4-(2,4,5-trifluorophenyl)-2-buten-1-one767340-03-454 % similar Sitagliptin deamino impurity 11253056-18-652 % similar