Greener Synthesis of Sulfosuccinimidyl 6-((4-azido-2-nitrophenyl) amino) hexanoate

Abstract

The current manufacturing process for Sulfosuccinimidyl 6-((4-azido-2-nitrophenyl) amino)hexanoate (Sulfo-SANPAH) involves an organic solvent system containing 60% acetone to synthesize 6-((4-azido-2-nitrophenyl) amino)hexanoic (AMPAH) acid, the precursor to the final structure. Though acetone is relatively safe, there is a potential method to mitigate flammability risks during production by using only water as the solvent to synthesize AMPAH acid. This hetero-bifunctional crosslinker, essential for cell-surface protein crosslinking, contains dual reactive groups: a photoreactive nitrophenyl azide and an amine-reactive Sulfo N-hydroxy succinimide (NHS) ester. The molecular design preserves both the nitrene group formation under UV exposure for C-H, N-H, and ring expansion insertions, and the NHS ester reactivity with primary amines at pH 7-9 for stable amide bond formation. The method of synthesizing the precursor to Sulfo-SANPAH demonstrated equivalent sulfonation efficiency to the original material while significantly reducing process safety risks. This improved synthetic approach provides a safer manufacturing route for this important biological conjugation reagent.No embargoAcademic Major: Pharmaceutical Science