Ambient Temperature Synthesis of Triazole-4-carbaldehyde Reagent by Dimroth Rearrangement Enabling Facile N-Terminal-specific Modification and Immobilization of Proteins

A facile method for the preparation of the N-terminal-specific modification reagent, 1 H -1,2,3-triazole-4-carbaldehyde (TA4C), using 1-(4-cyano-2,3,5,6-tetrafluorophenyl)-1 H -1,2,3-triazole-4-carbaldehyde derivative precursors, has been developed. This method allows direct conversion from a starting compound tethering a primary amine through the Dimroth rearrangement reaction at 25 °C. The resulting TA4C reagent exhibits excellent specificity for the N-terminal modification of proteins. The TA4C reagent enables versatile protein conjugation to various functional molecules, including useful handles and functional groups such as azides, alkynes, and amino acid derivatives. Furthermore, this method also facilitates N-terminal-specific immobilization of proteins onto resins, allowing the purification of N-terminal-modified proteins from unmodified proteins. The proteins and enzymes immobilized onto the resin via the N-terminus fully retain their inherent functions.