Thioamycolamide A (1) is a biosynthetically unique cytotoxic cyclic microbial lipopeptide that bears a d-configured thiazoline, a thioether bridge, a fatty acid side chain, and a reduced C-terminus. It has gained attention for its unique structure, and very recently we reported the total synthesis of 1 via a biomimetic route. The NMR spectra of synthetic 1 agreed with those of natural 1. However, structural identity between peptidic natural and synthetic compounds is often difficult to confirm by comparison of NMR spectra because their NMR spectra vary depending on the conditions in the NMR tube, which often result in the structural misassignment of peptidic compounds. Especially, our total synthesis based on the putative biomimetic route potentially gives 1 as a diastereomixture at the final step. The problem is that the diastereomers of peptidic mid-sized molecules often exhibit similar properties (such as NMR spectra and bioactivities), and their separation procedures are often laborious. Herein we report the structural confirmation of synthetic 1 by the LC–MS-based chromatographic comparison with the use of our highly sensitive labeling reagent l-FDVDA; the highly sensitive-advanced Marfey’s method (HS-advanced Marfey’s method). This work demonstrated the utility of our highly sensitive labeling reagent for the structural determination of not only scarce natural products but also readily isomerizable synthetic compounds.

硫代酰胺酰胺A（1）是一种生物合成独特的细胞毒性环状微生物脂肽，带有d构型的噻唑啉，硫醚桥，脂肪酸侧链和还原的C末端。它因其独特的结构而受到关注，最近，我们报道了通过仿生途径的1的全合成。合成的NMR谱1与那些自然同意1。但是，肽天然化合物和合成化合物之间的结构同一性通常难以通过NMR光谱的比较来确认，因为它们的NMR光谱根据NMR管中的条件而变化，这通常会导致肽化合物的结构错误分配。尤其是，我们基于推定仿生途径的总合成可能在最后一步产生非对映混合物1。问题在于肽中等大小分子的非对映异构体通常表现出相似的性质（例如NMR光谱和生物活性），并且它们的分离过程通常很费力。本文我们报告的合成的结构确认1通过利用我们的高度敏感的标记试剂的LC-MS为基础的色谱对比升-FDVDA; 高灵敏度先进的Marfey方法（HS先进的Marfey方法）。这项工作证明了我们的高灵敏度标记试剂不仅可用于结构测定稀有天然产物，而且还可用于易于异构化的合成化合物。