AN IMPROVED PROCESS FOR THE PREPARATION OF FOSAPREPITANT HAVING IMPROVED PURITY.

摘要

The present invention relates to an improved process for the preparation of [3- {[(2R,35)-2-[(lR)-l-[3,5-bis(trifluoromethyl)phenyI] ethoxy]-3-(4- fluorophenyl)morpholin-4-yl]methyl}-5-oxo- 2H-l,2,4-triazol-l-yl]phosphonic acid (Fosaprepitant or the compound of formula I) or its pharmaceutically acceptable salt, having palladium (Pd) content less than 1 ppm comprising catalytic hydrogenation of the compound of formula II with Pd catalyst optionally in the presence of base, to give the compound of formula I or the pharmaceutically acceptable salt thereof, optionally isolating the compound of formula I or the pharmaceutically acceptable salt and treating the compound of formula I or the pharmaceutically acceptable salt thereof twice with the metal scavenger to obtain the compound of formula I or the pharmaceutically acceptable salt thereof having Pd content less than 1 ppm.