Highly Sensitive Labeling Reagents for Scarce Natural Products
Takefumi Kuranaga, Mayuri Minote, Ryota Morimoto, Chengqian Pan, Haruka Ogawa, Hideaki Kakeya
Abstract
Scarce natural products that possess unique biological activities have been ideal drug leads for decades. However, their identification and structural determinations are problematic owing to sample amount limitation. Inspired by an extremely rare natural product yaku’amide B (10), highly sensitive labeling reagents that would be powerful tools for scarce natural product chemistry were designed and synthesized in this study. By fusion with the key structural motif for the structural revision of 10, the detection sensitivities of amino acid labeling reagents were drastically enhanced in LC–MS analysis. These advanced labeling reagents enabled the detection of infinitesimal amounts of amino acids and peptide hydrolysates. This sensitivity-enhancement design concept was also applicable to reagents for labeling saccharides and reactivity-guided isolation of electrophilic natural products. Details of these reagents, including their practical preparations and extended applications, are also provided.