Colorimetric Carbonyl Sulfide (COS)/Hydrogen Sulfide (H2 S) Donation from γ-Ketothiocarbamate Donor Motifs.

Hydrogen sulfide (H2 S) is a biologically active molecule that exhibits protective effects in a variety of physiological and pathological processes. Although several H2 S-related biological effects have been discovered by using H2 S donors, knowing how much H2 S has been released from donors under different conditions remains challenging. Now, a series of γ-ketothiocarbamate (γ-KetoTCM) compounds that provide the first examples of colorimetric H2 S donors and enable direct quantification of H2 S release, were reported. These compounds are activated through a pH-dependent deprotonation/β-elimination sequence to release carbonyl sulfide (COS), which is quickly converted into H2 S by carbonic anhydrase. The p-nitroaniline released upon donor activation provides an optical readout that correlates directly to COS/H2 S release, thus enabling colorimetric measurement of H2 S donation.