Patent ID: 7273921

Claim:
A method for producing an N-acylated peptide, said method comprising: a) reacting a peptide having at least one free amino group with an acylating agent of the general fonnula I wherein n is 0-8; R 1 is COOR 4; R 2 is a lipophilic moiety; R 3 together with the carboxyl group to which R 3 is attached designate a reactive ester or a reactive N-hydroxy imide ester; and R 4 is selected from the group consisting of hydrogen, C 1-12 -alkyl and benzyl, under basic conditions in an aqueous mixture containing less than 10% w/w aprotic polar solvent; wherein the acylating agent is added to the reaction mixture as a solution in the aprotic polar solvent and the acylating agent/aprotic polar solvent solution is stabilized by the presence of an acid, wherein said acid is selected from the group consisting of sulphuric acid, methanesulphonic acid and trifluoroacetic acid; and b) if R 4 in the acylating agent of step a) is not hydrogen, saponifying the acylated peptide ester group (COOR 4 ) under basic conditions; in order to produce said N-acylated peptide.