Patent ID: 7718598

Claim:
A method of a) synthesis of a linear or cyclic peptide; b) synthesis of a C-terminal modified peptide; or c) on-resin cyclization of a peptide molecule, said method comprising at least the step of linking a cyclic aromatic auxiliary compound of General Formula II to a primary amine nitrogen atom of an amino acid, or of a peptide which is to be cyclized or modified, to form a secondary amine, in which XH is OH, SH, CH 2 OH, or CH 2 SH at position 2 or 3; Y is an electron-withdrawing group at position 5 or 6; Z is any group which allows the formation of a covalent carbon-nitrogen bond; and R 3 , R 4 and R 5 are each independently selected from the group consisting of hydrogen, alkyl, aryl, hydroxy, alkoxy, aryloxy and a covalent linkage to a solid support; and in which R 3 and R 4 , or R 4 and R 5 can optionally together with the ring form a 5-, 6-, or 7-membered ring, thereby to facilitate conversion of the secondary amine to an amide, activating the carboxylic acid group of the amino acid, or of a peptide which is to be cyclized or modified, and converting the secondary amine to an amide.