Patent ID: 7528228

Claim:
A method for preparing a peptide of general formula R 1 R 2 NCH 2 —C(═O)—HN-A-COOH (I) in which A is a peptide chain comprising at least two enantiopure amino acids; and R 1 and R 2 are each H, HN represents the terminal amino group of A and COOH represents the terminal carboxyl group of A, comprising a) producing a compound of general formula XCH 2 —C(═O)—HN-A-COOY (II); wherein X is a group which can be substituted by nucleophilic substitution, chosen from Cl and Br; Y is selected from the group consisting of H, Li + , Na + , K + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ; A has the same meaning as in formula (I); HN represents the terminal amino group of A; and COOY represents the terminal carboxyl group of A, by peptide coupling of a fragment of general formula XCH 2 —C(═O)—HN—B (VI) wherein X is a group which can be substituted by nucleophilic substitution, chosen from Cl and Br, B is an amino acid or a peptide chain optionally bearing protective and/or activating groups, HN represents the α- amino group when B is an amino acid or the terminal amino group of B when B is a peptide, with a fragment F, wherein fragment F is a persilylated amino acid or a persilylated peptide chain; and b) reacting said compound of general formula (II) as defined in a) with a compound of general formula HNR 1 R 2 (III) in which R 1 and R 2 are each H, wherein the reaction is carried out at a temperature of −30° C. to +60° C.