The invention relates to a method for preparing nesiritide. The specific steps of the invention are: A) synthesizing the
tripeptide fragment H-Arg(Boc)2-Arg(Boc)2-His(Trt)-OtBu by a
liquid phase method; B) ) using
solid-
phase synthesis method, starting with 2-CTC-resin, and sequentially
coupling amino acids with N-terminal Fmoc protection and
side chain protection according to the
peptide sequence of nesiritide main chain 1-29; C) in
organic base Under certain conditions,
iodine was used to fix the ring; D) cleavage to obtain the fully protected nesiritide main chain 1-29
peptide fragment; E)
tripeptide fragment H-Arg(Boc)2-Arg(Boc)2-His(Trt)
Coupling of ‑OtBu and fully protected nesiritide main chain 1‑29
peptide fragment; F) cleavage, purification, and lyophilization to obtain nesiritide. The invention provides a high-purity, low-cost nesiritide preparation process suitable for large-scale production. This process can not only effectively control the racemic peptide
impurity D‑His32‑nesiritide and the missing peptide
impurity Des‑Arg31‑nesiritide
Peptide or Des‑Arg30‑nesiritide, the yield of nesiritide was also improved by optimizing the ring fixation conditions.