Solid-Phase Synthesis of aβ-Dodecapeptide with Seven Functionalized Side Chains and CD-Spectroscopic Evidence for a Dramatic Structural Switch When Going from Water to Methanol Solution
作者:Jürg V. Schreiber、Dieter Seebach
DOI:10.1002/1522-2675(20001220)83:12<3139::aid-hlca3139>3.0.co;2-w
日期:2000.12.20
missing in the CD spectrum, only a strong positive Cotton effect at 202 nm was observed, indicating the presence of β-peptidic secondary structures, containing ten-membered H-bonded rings, such as the 12/10 helix (Fig. 4, right) or the hairpin. Only a detailed NMR solution-structure analysis will provide the clues necessary for understanding the effects leading to the observed dramatic structural change of
应用 Fmoc 方法和 Wang 树脂,通过手动固相技术合成了数毫克的全β3-十二肽,具有受保护的 N 端硫醇锚定基团和七个侧链。序列为β-HLys-β-HPhe-β-HTyr-β-HLeu-β-HLys-β-HSer-β-HLys-β-HPhe-β-HSer-β-HVal-β-HLys-β-HAla -OH(从 N 端到 C 端;见 1)。结构单元侧链中的官能团被 Boc (β-HLys) 或 t-Bu 醚 (β-HSer, β-HTyr) 保护,以允许用三氟乙酸同时脱保护和从树脂上脱离。所有偶联步骤均使用 HBTU(=O-(1H-苯并三唑-1-基)-1,1,3,3-四甲基脲六氟磷酸盐)/HOBt(=1-羟基-1H-苯并三唑)在 DMF 中实现。对于 Fmoc (=(9H-fluoren-9-yl)methoxycarbonyl) 脱保护,当链长超过七个或八个氨基酸部分时,开发了一种方案以克服先前报道的