Synthesis of Cyclic Hexapeptides Based on the Antibiotic Cyclic Decapeptide Loloatin C by an in situ Indirect Cyclization Method
作者:Heru Chen、Richard K. Haynes、Jürgen Scherkenbeck
DOI:10.1002/ejoc.200300477
日期:2004.1
Three cyclic hexapeptide units based on the parent loloatin C scaffold have been identified by a ‘sliding window’ method as part of an expeditious SAR search for the basis of the antibiotic activity of the loloatins. Modified Fmoc-based solid-phase synthesis was used to prepare cyclic(L-valyl-Lornithyl-D-phenylalanyl-L-asparaginyl-L-aspartyl-L-tryptophanyl) and cyclic(L-valyl-L-ornithyl-L-leucyl-L
三个基于母体 Loloatin C 支架的环状六肽单元已通过“滑动窗口”方法鉴定,作为快速 SAR 搜索的一部分,以寻找 Loloatins 的抗生素活性基础。基于改性Fmoc的固相合成用于制备环状(L-缬氨酰-Lornithyl-D-苯丙氨酰-L-天冬酰胺酰-L-天冬氨酰-L-色氨酸)和环状(L-缬氨酰-L-鸟氨酰-L-亮氨酰) -L-色氨酸基-D-苯丙氨酰基-L-天冬酰胺基),总产率为42%-47%。专门开发了一种结合原位间接环化的新溶液法制备环状(L-鸟酰基-L-亮氨酰基-D-酪氨酰基-L-脯氨酰基-L-色氨酸基D-苯丙氨酰基),包括线性肽通过氨基亮氨酸中的基团,选择性地从 Fmoc 保护的胺原位释放,并带有活化的鸟氨酸对硝基苯基酯。该方法还有效地用于前两个环状六肽的线性前体的环化。NOE 分析结合肽主链建模用于建立目标化合物的构象。都具有带γ-转角的螺旋状结构。(© Wiley-VCH