Abstract: The peptides Ac-D-2Nal-D-4ClPhe-D-3Pal-OH and Boc-D-2Nal-D-4ClPhe-D-3Pal-OH are intermediates useful in the synthesis of LHRH analogs by coupling with suitable heptapeptides, in particular with the heptapeptides P1-Ser(P2)-MMeTry(P3)-D-Lys(Nic)-Leu-Lys(iPr,P4)-Pro-D-AlaNH2 and P1-Ser(P2)-NMeTry(P3)-D-Asn-Leu-Lys(iPr,P4)-Pro-D-AlaNH2.

Abstract: The peptides Ac-D-2Nal-D-4ClPhe-D-3Pal-OH and Boc-D-2Nal-D-4ClPhe-D-3Pal-OH are intermediates useful in the synthesis of LHRH analogs by coupling with suitable heptapeptides, in particular with the heptapeptides P1-Ser(P2)-MMeTry(P3)-D-Lys(Nic)-Leu-Lys(iPr,P4)-Pro-D-AlaNH2 and P1-Ser(P2)-NMeTry(P3)-D-Asn-Leu-Lys(iPr,P4)-Pro-D-AlaNH2.

Abstract: A nona- or decapeptide is purified from residual organic solvent by dissolving in a solvent comprising water and at least one C1–C3 alcohol followed by precipitation into a vigorously stirred solvent consisting of an alkyl ester of a carboxylic acid, the ester comprising from 3 to 6 carbon atoms, and one or several non-polar compounds selected from hexane, heptane, octane, cyclohexane, methylcyclohexane, and, optionally, of up to 5% of acetic or propionic acid, isolating the precipitated nona- or decapeptide, followed by washing with a mixture of C3–C5 esters and drying, with the provisio that the water content of the solvent comprising water and the at least one alcohol is below 8% (v/v), and that the volume ratio of the dissolution solvent mixture and the precipitation solvent mixture is 1:10 or higher. Also described is the monoacetate of Ac-D-2Nal-D-4ClPhe-D-3Pal-Ser-MeTyr-D-Asn-Leu-Lys(iPr)-Pro-D-Ala-NH2.