A peptidomimetic of the turn in the helix-turn-helix (HTH) motif of DNA-binding proteins was designed and synthesized. Conformational constraint was achieved by an unusual linking of two amino acids with a side-chain carbon--carbon bond. A phenyl ring provides the potential for new hydrophobic contacts with the hydrophobic core of the HTH motif. In the mimic, the peptide backbone and the central residue were retained in native form within a 12-membered cyclic tripeptide. The target compound 1b was synthesized by two sequential Horner-Wittig couplings followed by enantioselective hydrogenation with Rh(MeDuPHOS) in 8 steps and 35% overall yield. The stereochemical outcome of the key hydrogenation was determined by aromatic ring oxidation with RuO.sub.2 /NalO.sub.4 to give two equivalents of Boc-Asp-OMe.
一种仿肽设计并合成了DNA结合蛋白中螺旋-螺旋-螺旋(HTH)基序的仿生体。通过两个
氨基酸的侧链碳-碳键连接实现构象限制。苯环提供了与HTH基序疏
水核心形成新疏
水接触的潜力。在仿生体中,肽骨架和中心残基在一个12元环三肽中以原生形式保留。目标化合物1b通过两个顺序的Horner-Wittig偶联反应,随后在Rh(MeDuPHOS)的选择性加氢下,经过8个步骤和35%的总产率合成。关键氢化的立体
化学结果通过RuO.sub.2 / NalO.sub.4的芳香环氧化确定,生成两个Boc-Asp-OMe当量。