Solid-liquid phase synthesis method of Bremelanotide

Abstract

The invention discloses a solid-liquid phase synthesis method of Bremelanotide. The method comprises the following steps: synthesizing an AC-Nle-Asp-O-2-Phipr dipeptide fragment by virtue of a liquidphase method; coupling a main chain and a side chain of the Lys respectively to prolong a peptide sequence, obtaining Fmoc-His(Boc)-D-Phe-Arg(pbf)-Trp(Boc)-Lys(AC-Nle-Asp-O-2-Phipr)-Wang resin, and after the protecting group is removed, cyclizing the main chain and the side chain. The head and the tail are prevented from being folded into a ring, the problem of large steric hindrance of the foldedring is solved, and the influence of the formed peptide on the non-formed peptide is also reduced to the minimum due to the fact that the ring forming sites are closer. In addition, alkali is not adopted for hydrolysis, and corresponding impurities cannot be generated. The Bremelanotide synthesized by the synthesis method is high in purity, low in cost and suitable for large-scale production.

Description

technical field [0001] The invention relates to a solid-liquid phase synthesis method of bumenotide, which belongs to the technical field of polypeptide synthesis. Background technique [0002] Bremelanotide, English name Bremelanotide, was originally researched and developed by the University of Arizona. Its target is MC3R / MC4R. Its structure belongs to peptide analogs and is used for the treatment of premenopausal female libido disorder; Paladin Company obtained the research and development rights of this compound in 2007. , then entered the development, and the clinical research was concentrated in North America; in March 2018, the NDA application was submitted to the US FDA, and it was approved by the FDA on June 21, 2019. Bumenotide is composed of 7 amino acids and has the same core sequence as α-melanocyte-stimulating hormone, the receptor of which plays an important role in appetite and sexual arousal. Its peptide sequence is AC-Nle-[Asp-His-D-Phe-Arg-Trp-Lys]cycle-O...

AI Technical Summary

Problems solved by technology

Solid-phase cyclization is mainly to remove the protection after coupling the main chain, and the peptide chain is connected end to end, but the peptide chain is difficult to fold to end to end due to too much steric hindrance, which leads to low efficiency and large steric hindrance. The reasons include the following two aspects: (1) the various protecting group structures on the peptide chain make the peptide chain have a rigid structure, which is difficult to fold back into a ring; (2) after the ring is formed, the cyclic peptide has a larger Spatial structure, making it difficult for uncycled peptides to fold back into a ring

Patent CN200610086841.4 adopts a step-by-step synthesis method. After the peptide resin is synthesized, the protective groups of Asp and Lys are selectively removed, and then a ring is formed on the resin, and finally cracked with HF. Because of the severe corrosiveness of HF, this method cannot It is used on a large scale, and the yield of refined peptides published in the examples is 30-35%; patent CN200710048824.6 also adopts the method of selective deprotection, but the deprotection method selected by it is effective in removing the protection of Asp and Lys side chains. The protective group Trt of His will also be removed at the same time, and the yield of the crude peptide disclosed in the examples is 80%; in the solid-phase synthesis method of patent CN200910131598.7, p-hydroxybenzoic acid is connected after RinkAmideResin, Then use ordinary amino acid raw materials to synthesize step by step. After the synthesis, it is cracked with TFA and formed into a ring under liquid phase conditions. However, intermolecular coupling is prone to occur during liquid phase ring formation, resulting in polymers such as dimers and trimers. , seriously reducing the synthesis yield; in patent 201610070195.6, HO-(CH2)n-COOH is used as the linker connecting the solid phase carrier and the target peptide to form a ring on the resin. This method modifies the linker structure of the resin and introduces a long The chain lipid bond overcomes the second reason of large steric hindrance, but the problem of being difficult to fold into a ring does not work very well, and an alkaline solution is used in the process of cutting the lipid bond, and the solution produces various degradation impurities , affecting yield and purity

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