Complementary to hydrophobic five membered ring β-amino acids (e.g. ACPC), β-sugar amino acids (β-SAAs) have found increasing application as hydrophilic building blocks of foldamers and α/β chimeric peptides. Fmoc-protected β-SAAs [e.g. Fmoc-RibAFU(ip)-OH] are indeed useful Lego elements, ready to use for SPPS. The removal of 1,2-OH isopropylidene protecting group increasing the hydrophilicity of such SAA is presented here. We first used N₃-RibAFU(ip)-OH model compound to optimize mild deprotection conditions. The formation of the 1,2-OH free product N₃-RibAFU-OH and its methyl glycoside methyl ester, N₃-RibAFU(Me)-OMe were monitored by RP-HPLC and found that either 50% TFA or 8 eqv. Amberlite IR-120 H⁺ resin in MeOH are optimal reagents for the effective deprotection. These conditions were then successfully applied for the synthesis of chimeric oligopeptide: -GG-X-GG- [X=RibAFU(ip)]. We found the established conditions to be effective and—at the same time—sufficiently mild to remove 1,2-O-isopropylidene protection and thus, it is proposed to be used in the synthesis of oligo- and polypeptides of complex sequence combination.

与疏水性五元环 β-氨基酸 (例如 ACPC) 互补，β-糖氨基酸 (β-SAA) 已发现越来越多地用作折叠聚体和 α/β 嵌合肽的亲水构建块。Fmoc 保护的 β-SAA [例如 Fmoc-RibAFU(ip)-OH] 确实是有用的乐高元件，可用于 SPPS。此处介绍了 1,2-OH 异亚丙基保护基团的去除，从而增加了此类 SAA 的亲水性。我们首先使用 N ₃ -RibAFU(ip)-OH 模型化合物来优化温和的脱保护条件。1,2- OH自由产物N的形成₃ -RibAFU- OH和其甲基糖苷甲酯，N ₃ - -RibAFU（Me）的OME通过RP-HPLC监测，发现为50％TFA或8当量。Amberlite IR-120 H⁺ MeOH 中的树脂是有效脱保护的最佳试剂。然后将这些条件成功应用于嵌合寡肽的合成：-GG- X- GG-[X=RibAFU(ip)]。我们发现既定条件是有效的，同时足够温和以去除 1,2- O-异亚丙基保护，因此，建议将其用于合成复杂序列组合的寡核苷酸和多肽。