Peptides are still difficult to synthesize when they contain sterically hindered amino acids, such as α,α-disubstituted amino acids and N-substituted amino acids. In this study, solid-phase syntheses of oligopeptides containing multiple α-aminoisobutyric acid (Aib) residues were performed in high yields by using a nonswellable resin as the solid-support and 3-nitro-1,2,4-triazol-1-yl-tris(pyrrolidin-1-yl)phosphonium hexafluorophosphate (PyNTP) as the condensing reagent.

中文翻译：

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以3-硝基1,2,4-三唑-1-基-三（吡咯烷-1-基）六氟磷酸（（PyNTP）为缩合剂在固溶性树脂上固相合成含位阻氨基酸的寡肽

当肽包含空间受阻氨基酸时，例如α，α-二取代氨基酸和N-取代氨基酸，仍难以合成。在这项研究中，通过使用不可溶胀的树脂作为固相载体和3-硝基-1,2,4-三唑-1-，以高产率进行了包含多个α-氨基异丁酸（Aib）残基的寡肽的固相合成。六氟磷酸基-三（吡咯烷-1-基）phosph（PyNTP）作为缩合剂。