摘要:
There is provided a process for the preparation of sitagliptin or a pharmaceutically acceptable salt thereof, and a process for the preparation of intermediate compounds useful in the preparation of sitagliptin. In particular, there is provided a process comprising condensing 3-tert-butoxycarbonylamino-4-(2,4,5-trifluorophenyl) butyric acid of formula (II) with 3-(trifluoromethyl)-5,6,7,8-tetrahydro-[l,2,4]triazolo[4,3-a] pyrazine of formula (III) or a salt thereof in presence of a catalyst to obtain (R)-tert-butyl-4-oxo-4-(3- (trifluoromethyl)-5,6-dihydro-[ 1,2,4]-triazolo[4,3-a]pyrazin-7(8H)-yl)- 1 -(2,4,5- trifluorophenyl)butan-2-yl-carbamate of formula (IV) or a pharmaceutically acceptable salt thereof. The catalyst is represented by the compound of formula (V). Compound of formula (IV) or its pharmaceutically acceptable salt obtained may be deprotected to obtain a compound of formula (I).