Synthesis and CD Spectra in MeCN, MeOH, and H2O ofγ-Oligopeptides with Hydroxy Groups on the Backbone, Preliminary Communication
作者:Meinrad Brenner、Dieter Seebach
DOI:10.1002/1522-2675(20010516)84:5<1181::aid-hlca1181>3.0.co;2-0
日期:2001.5.16
Boc-Ala-OH, Boc-Val-OH, and Boc-Leu-OH, and NaBH4 reduction of the methyl 4-amino 3-oxo carboxylates formed (Scheme 2). The N-Boc hydroxy amino acids were coupled in solution to give the γ-peptides. CD Spectra of the new types of γ-peptides were recorded and compared with those of simple γ2-, γ3-, γ4-, and γ2,3,4-peptides (Figs. 3, 4, and 5). An intense Cotton effect at ca. 200 nm ([Θ]=−2⋅105 deg⋅cm2⋅dmol−1)
已制备 γ4-三肽和 γ4-六肽,1-4,每个残基的 2 位或 3 位具有 OH 基团。相应的 2-羟基氨基酸通过 Si-nitronate (3+2) 环加成到 Oppolzer's sultam 的丙烯酰基衍生物和得到的 1,2-恶唑烷的 Raney-Ni 还原获得(方案 1)。3-羟基氨基酸衍生物是通过 Boc-Ala-OH、Boc-Val-OH 和 Boc-Leu-OH 的 Claisen 缩合以及 NaBH4 还原形成的 4-氨基 3-氧代羧酸甲酯制备的。方案2)。N-Boc 羟基氨基酸在溶液中偶联得到 γ-肽。记录了新型γ-肽的CD光谱,并与简单的γ2-、γ3-、γ4-和γ2,3,4-肽进行了比较(图3、4和5)。大约有强烈的棉花效果。200 nm ([Θ]=−2⋅105 deg⋅cm2⋅dmol−1) 表明由 (3R,4S)-4-氨基-3-羟基酸构成的六肽(具有 Val、Ala、Leu