“… With this small alteration comes a large increase in water solubility and reactivity toward primary amines at a physiologically compatible pH range of pH = 7–9 . Since its invention in 1973, the Traut’s reagent has been continuously used to modify biological molecules (e.g., proteins, enzymes, ribosomes) and anchor them to surfaces, , tags, , or other (bio)macromolecules. , Despite its popularity, Traut’s reagent can only be purchased as an unsubstituted five-membered heterocycle. ITL derivatives with substitutions on the heterocycle have only been reported twice by Carroll and co-workers. , In the respective publications, the authors investigated the impact of various alkyl and phenyl substitutions on the reactivity and stability of the ITL derivatives.…”