Assembly of indole fluorophore in situ for hydrogen sulfide signaling through substrate triggered intramolecular reduction–cyclization cascade: a sensitive and selective probe in aqueous solution

Abstract

The fluorescence enhancement is due to the formation of the indole fluorophore through reduction by H2S and cyclization.

Coumarin-Based Small-Molecule Fluorescent Chemosensors

“…Another 6-azide coumarin derivative 259 was developed as H 2 S receptor by Qian’s group . A formylmethyl group was located at the 7-position of coumarin to spontaneously condense with the amine at 6-position, resulting from the reduction of azide (Figure ).…”

“…Another 6-azide coumarin derivative 259 was developed as H 2 S receptor by Qian's group. 344 A formylmethyl group was located at the 7-position of coumarin to spontaneously condense with the amine at 6-position, resulting from the reduction of azide (Figure 162). Thus, the fluorophore is assembled in situ through a H 2 S triggered intramolecular reduction-cyclization cascade and finally produces a highly fluorescent indole-fused coumarin.…”

Luminescent probes for the bioimaging of small anionic species in vitro and in vivo

“…One 68-Cu(II) treated mouse was then injected with Na 2 S (as source of HS À ) and the fluorescence images were recorded (l ex = 670 nm, l em = 790 nm). The fluorescence signal increased seven-fold 1 h after treatment with HS À (compared to the control) and continued to rise gradually over 5 h. In order to keep this section to a reasonable length and highlight the most relevant recent examples it was not possible to include all recent examples of probes functioning by way of (i) nucleophilicity 100,218,219,223,224,[239][240][241][242][243][244][245][246][247] (ii) reduction (arylazides, [226][227][228][231][232][233][234][235][248][249][250][251][252][253][254][255][256][257][258] sulfonylazides, [259][260][261] nitro groups, 262,263 hydroxyl amines, 264 and N-oxides 265 ) as well as (iii) displacement 53,[266][267][268]…”

“AND” luminescent “reactive” molecular logic gates: a gateway to multi-analyte bioimaging and biosensing

“…15). Interestingly, alternative reactions such as aldolisation-elimination 33 (or related reactions), 34 Mannich cylisation 35 (or related intramolecular addition-elimination reactions), 36,37 phenylogous Vilsmeier-Haack, 38 S E Ar 39,40 or tandem phenol oxidation-Michael addition 41 has been also implemented to detect various (bio) analytes including G-quadruplex DNA structures, penicillin G acylase (PGA), monoamine oxidases (MAO A and B), sarin mimics, NO and peroxynitrite (OONO − ) through the formation of cyanine, pyronin B, pyrazino-benz [e]indole, pyrrolocoumarin, diazachrysene and resorufin fluorescent scaffolds respectively (Fig. 16).…”