Accelerated microfluidic native chemical ligation at difficult amino acids toward cyclic peptides

Abstract

Cyclic peptide-based therapeutics have a promising growth forecast that justifies the development of microfluidic systems dedicated to their production, in phase with the actual transitioning toward continuous flow and microfluidic technologies for pharmaceutical production. The application of the most popular method for peptide cyclization in water, i.e., native chemical ligation, under microfluidic conditions is still unexplored. Herein, we report a general strategy for fast and efficient peptide cyclization using native chemical ligation under homogeneous microfluidic conditions. The strategy relies on a multistep sequence that concatenates the formation of highly reactive S-(2-((2-sulfanylethyl)amino)ethyl) peptidyl thioesters from stable peptide amide precursors with an intramolecular ligation step. With very fast ligation rates (<5 min), even for the most difficult junctions (including threonine, valine, isoleucine, or proline), this technology opens the door toward the scale-independent, expedient preparation of bioactive macrocyclic peptides.

A gold mine for drug discovery: Strategies to develop cyclic peptides into therapies

“…By employing this TEA‐thioester surrogate, the cyclic peptide KB1 has also been synthesized successfully (Figure B). In 2018, Monbaliu and Melnyk developed a scale‐independent and efficient microfluidic NCL strategy to prepare the bioactive macrocyclic peptides . As a demonstration, the synthesis an antibacterial cyclopeptide, namely RTD‐1, was performed from three different precursors and obtained in good yields (from 29% to 37% isolated).…”

Continuous Flow Organophosphorus Chemistry

“…Several phosphine derivatives can also be employed as reductants. In 2018, Monbaliu and Melnyk [122] reported a microfluidic system of the preparation of cyclic peptides. The process relied on an adaptation of the classical Native Chemical Ligation (NCL) methodology [123] that was here transposed to microfluidic conditions.…”

“…Continuous flow Native Chemical Ligation towards cyclic peptides involving tris(2-carboxyethyl)phosphine hydrochloride as reductant. [122]…”

Peptide Synthesis Utilizing Micro‐flow Technology

“…[45] An aqueous solution of amide 75 that was obtainedf rom the reduction of 74, TCEP,a nd HCl was introduced to the micro-flow reactor from inlet A. Decane was introduced into the reactor from inlet Bt o suppress the undesired dispersion effect. [45] An aqueous solution of amide 75 that was obtainedf rom the reduction of 74, TCEP,a nd HCl was introduced to the micro-flow reactor from inlet A. Decane was introduced into the reactor from inlet Bt o suppress the undesired dispersion effect.…”