Dihydroindeno[1,2-b]pyrroles: new Al³⁺selective off–on chemosensors for bio-imaging in living HepG2 cells

Abstract

In this study, a new molecular organic probe has been designed and synthesized by using recyclable, inexpensive and non-toxic polyethylene glycol (PEG-400) as a promoting reaction medium in water under environmentally benevolent conditions. The probe has been explored as a potential chemosensor to detect Al3+ ions using a HEPES buffer (pH = 7.4) solution. Investigations of the fluorescence behaviour of this sensor in DMSO/H2O (2 : 8, v/v) solution displayed a dramatic switch-on response only in the presence of Al3+, while other metal ions, like Li+, Na+, K+, Ag+, Ca2+, Mg2+, Mn2+, Ba2+, Cu2+, Ni2+, Co2+, Fe2+, Zn2+, Cd2+, Hg2+, Pb2+, Sr2+, Fe3+ or Cr3+, have almost no influence on the fluorescence behaviour. Various common anions, such as ClO4-, Cl-, or NO3- in the form of Al3+ salts [e.g. Al(ClO4)3, AlCl3 or Al(NO3)3], had no influence on the fluorescence behaviour of the sensors. The detection limit for Al3+ is in the order of 10-6 M in DMSO/H2O (2 : 8, v/v) HEPES buffer (pH = 7.4) solution. Notably, this is the first report of a dihydroindeno[1,2-b]pyrrole moiety acting as a sensor for the selective detection of Al3+ ions through an off-on fluorescence response. The potential of the probe was also confirmed by employing it for fluorescence bio-imaging with Al3+ on HepG2 cells.

Recent applications of ninhydrin in multicomponent reactions

“…A new class of ninhydrin-based organic molecular probes, namely, dihydroindenopyrrole 9 was synthesized by Mukhopadhyay et al In non-toxic polyethylene glycol-water (PEG 400water), the reaction between ninhydrin 1, aniline 2 and dialkyl acetylenedicarboxylate (DAAD) 8 proceeded smoothly to achieve the novel product 9. 76 A plausible mechanism is shown in Scheme 3, where amine 2 reacts with diester 8 to produce the enaminediester intermediate A. Then, intermediate A acts as a nucleophile to attack the central carbonyl of 1 to obtain intermediate B, which generates intermediate C upon dehydration.…”

Palladium‐Catalyzed Tandem Cyclization of 2‐(2 Ethynylphenyl)acetonitriles and Isocyanides: Access to Indeno[2,1‐b]pyrroles

“…Indenopyrroles are highly privileged heterocyclic scaffolds, widely found in medicinal chemistry owing to their pronounced biological activities, [1][2][3][4][5][6] such as human casein kinase II (CK2) inhibitors, [1] hypoglycemic agents, [2] angiotensin-converting enzyme inhibitor analogues, [3] antibacterial agents, [4] and antitumor. [5] For their potent applications, several synthetic methods have been developed for the preparation of indenopyrrole derivatives.…”

Ultrasound‐Assisted Expeditious Catalyst‐Free Green Approach towards Diastereoselective Synthesis of Spiro[indoline‐3,2′‐pyrido[2,1‐b][1,3]oxazine]‐3′,4′‐dicarboxylate Scaffolds

“…As part of our current studies towards the development of new routes for the synthesis of heterocyclic compounds, [35,36] here, we desire to report that pyridine proceeds a smooth reaction with dialkyl acetylenedicarboxylates in presence of N‐substituted isatins in aq. ethanol at room temperature to afford Spiro[indoline‐3,2′‐pyrido[2,1‐ b ][1,3]oxazine]‐3′,4′‐dicarboxylate derivatives in excellent yields.…”

“…[32] Additionally, the use of green solvents like aqueous ethanol not only reduces the utility of organic solvents, escaping of volatile organic solvents after the reaction, waste, but also enhances the reaction rate dramatically in many organic reactions. [33,34] As part of our current studies towards the development of new routes for the synthesis of heterocyclic compounds, [35,36] here, we desire to report that pyridine proceeds a smooth reaction with dialkyl acetylenedicarboxylates in presence of Nsubstituted isatins in aq. ethanol at room temperature to afford Spiro[indoline-3,2'-pyrido[2,1-b] [1,3]oxazine]-3',4'-dicarboxylate derivatives in excellent yields.…”