Patent ID: 8828938

Claim:
A method of manufacture of degarelix, Ac-D-2Nal-D-Phe(4Cl)-D-3Pal-Ser-4Aph(Hor)-D-4Aph(Cbm)-Leu-ILys-Pro-D-Ala-NH2, wherein Aph is 4-amino-phenylaniline, (Hor) is (L-hydroorotyl), and (Cbm) is (carbamoyl), containing 0.3% by weight or less of Ac-D-2Nal-D-Phe(4Cl)-D-3Pal-Ser-X-D-4Aph(Cbm)-Leu-ILys-Pro-D-Ala-NH2, wherein X is 4-([2-(5-hydantoyl)]acetylamino)-phenylalanine, comprising step-wise providing a solution of an amino acid or peptide in which an α-amino group is protected by Fmoc; contacting a solid support having an amino group linked thereto with the solution in the presence of reagent which forms a peptide bond between a carboxyl group of the dissolved amino acid or peptide and the amino group linked to the support for a time sufficient to form said peptide bond; removing Fmoc by contacting the support with an organic base selected from the group consisting of piperidine and C-alkyl substituted piperidine, wherein the alkyl is branched or straight chained and has from 1 to 6 atoms, in an organic solvent.