3′‐O‐(2‐Nitrobenzenesulfonyl)fluorescein as a Fluorescent Probe for Hydrogen Polysulfides by Straightforward One‐Step Deprotection

Abstract

AbstractTo develop a fluorescent probe for hydrogen polysulfides (H2Sn, n≥2) based on protection‐deprotection chemistry, we protected fluorescein with nitrobenzenesulfonyl groups bearing various substituents with different electrophilic reactivities, and evaluated their responsiveness toward H2Sn. 3′‐O‐(2‐Nitrobenzenesulfonyl)fluorescein (1 c) provided the best sensitivity toward H2Sn and selectivity over hydrogen sulfide and glutathione. Further evaluation demonstrated that 1 c was an excellent probe, comparable with PSP‐3, one of the best H2Sn probes developed to date. The attractive features of 1 c were capitalized on by synthesizing the acetylated derivative from 1 c, which was shown to be cell‐permeable and applicable to the fluorescent imaging of H2Sn in HeLa cells.