Patent ID: 7612209
Filing Date: 2009-11-03
Classification: C07K,Y02P

Abstract:
1. A process for the manufacture of the compounds of formula I: wherein: (1) R wherein said process comprises the following steps: (a) reacting an amino acid derivative of formula II: wherein R with serine or threonine to obtain a dipeptide of formula III: wherein R (b) adding the amine of formula V: wherein R to form the ammonium salt of the dipeptide of formula III in crystal form: wherein R (c) adding an acid to the ammonium salt in step (b) to release the free acid of the dipeptide of formula III from the ammonium salt, and removing the protonated amine from the reaction mixture; and (d) effecting the ring closure of the free acid of the dipeptide of formula III in step (c) with a compound selected from the group consisting of: wherein: (1) R in the presence of an acidic catalyst to obtain compounds of formula I.