ABSTRACT
Herein we have demonstrated the first report on 5-annulation of ketoimines to valuable isoindolinone-3-carboxylates. Instead of commonly used aldimine substrates, relatively less reactive ketoimines are employed for developing a TFA catalyzed organoreductive cyclization to furnish a variety of isoindolinones in excellent yield and reaction rate under mild reaction conditions. This is a metal-free event, which proceeds through a one pot ketoimine formation, hydride transfer from an organic reductant 2-(naphthalen-2-yl)-2,3-dihydrobenzo[ d]thiazole, and followed by five member cyclization sequences through TFA-activation of imine and ester groups. Studies on ESI-MS kinetics, leaving group aptitude, and control experiments led us to propose the mechanistic pathway of the new ketoimine-lactamization reaction. We have shown the synthetic utility of the emerging synthons through easy transformation of isoindolinones to different synthetic analogues. We investigated photophysical properties of the small molecules for their futuristic application as a pharmaceutical and materials, and the heterocycles displayed brilliant fluorescence activity.
ABSTRACT
A rapid fluorescent probe based on the conjugate of chromone and benzothiazole moiety was presented, which could selectively respond to HSO3- over other common anions and thiols. The function of the probe relies on nucleophilic addition to break down the π-conjugation. The probe can be used as a signal tool to determine HSO3- levels in sugar-based food and living cells.
ABSTRACT
A chemosensor was developed which could selectively detect and differentiate trivalent metal ions (Al(3+), Cr(3+) and Fe(3+)) upon single excitation at two different wavelengths in aqueous medium. This probe selectively detects trivalent ions in the presence of different metal ions in aqueous medium. It shows an excellent performance in the "dipstick" method.
Subject(s)
Aluminum/analysis , Chromium/analysis , Fluorescent Dyes/chemistry , Iron/analysis , Rhodamines/chemistry , Water/analysis , Cations/analysis , Naphthalenes/chemistry , Spectrometry, Fluorescence/methods , Spectrophotometry, Ultraviolet/methodsABSTRACT
A new pyrene based fluorescence probe has been synthesized for fluorogenic detection of Cu(2+) in acetonitrile-aqueous media (7 : 3 CH3CN-HEPES buffer, v/v, at pH 7.5) with bioimaging in both prokaryotic (Candida albicans cells) and eukaryotic (Tecoma stans pollen cells) living cells. The anion recognition properties of the sensor have also been studied in acetonitrile by fluorescence methods which show remarkable sensitivity toward fluoride over other anions examined.
Subject(s)
Bignoniaceae/cytology , Candida/cytology , Copper/analysis , Fluorescent Dyes/chemistry , Fluorides/analysis , Pyrenes/chemistry , Anions , Cell Survival , Fluorescent Dyes/chemical synthesis , Proton Magnetic Resonance Spectroscopy , Spectrometry, Fluorescence , Spectrophotometry, UltravioletABSTRACT
We have designed a chemodosimeter DPNO (weak fluorescence) which can be oxidized to HPNO (strong blue fluorescence) by OCl(-) with high selectivity and sensitivity in a ratiometric approach with a noticeably lower detection limit. The sensor could be useful for the detection of hypochlorites in tap water.
Subject(s)
Drinking Water/analysis , Fluorescent Dyes/chemistry , Hypochlorous Acid/analysis , Naphthalenes/chemistry , Limit of Detection , Models, Molecular , Spectrometry, Fluorescence/economics , Spectrometry, Fluorescence/methodsABSTRACT
A new rhodamine based chemosensor, cyano-rhodamine, has been designed and synthesized with a green approach which shows a specific 'C-CN' bond breaking with the action of the Pd(2+) ion to produce the specific color and fluorescence of rhodamine 6G itself in solution and in HeLa cells.
Subject(s)
Cyanides/chemistry , Palladium/analysis , Rhodamines/chemistry , Cyanides/chemical synthesis , HeLa Cells , Humans , Models, Molecular , Rhodamines/chemical synthesis , Spectrometry, FluorescenceABSTRACT
A hybrid carbazole hemicyanine dye (receptor CHD) was developed as a new visible and near infrared chemodosimeter type sensor with high ratiometric selectivity towards cyanide in the presence of other anions in aqueous solution. The chemosensor also showed excellent performance when used in the "dip stick" method, i.e. in solid phase (TLC plates).
ABSTRACT
The de-diaminomaleonitrile reaction in a simple carbazole diaminomaleonitrile hybrid (CDH) was promoted by OCl(-) which disrupted the ICT mechanism by breaking the donor and acceptor linkage. This system utilized an irreversible OCl(-) promoted oxidation reaction and it responded instantaneously at room temperature. The chemosensor also showed excellent performance in tap water and the "dip-stick" method.
Subject(s)
Carbazoles/chemistry , Fluorescent Dyes/chemistry , Hypochlorous Acid/analysis , Nitriles/chemistry , Water/analysis , Hypochlorous Acid/chemistry , Oxidation-ReductionABSTRACT
In this study, we have synthesized a simple Schiff base type isophthaloyl salicylaldehyde hydrazone (ISH) moiety which selectively detects Al(III) and PPi with a fluorescence enhancement at two different wavelengths in aqueous solution. The sensing phenomenon is also reversible and thus the sensor beautifully mimics logic gates (INHIBIT and EXOR gates).
Subject(s)
Aldehydes/chemistry , Aluminum/chemistry , Diphosphates/analysis , Fluorescent Dyes/chemistry , Hydrazones/chemistry , Schiff Bases/chemistry , Spectrometry, Fluorescence/instrumentation , Equipment Design , Sensitivity and SpecificityABSTRACT
For ratiometric "naked eye" detection of CN(-), an ESIPT exhibiting benzothiazole receptor (BHI) is designed having one aldehyde group ortho and the other aldehyde para to the OH group respectively. Due to RAHBs, the ortho aldehyde group is highly reactive undergoing nucleophilic cyanide addition selectively, which hampered ESIPT. This is also supported by DFT and TD-DFT calculations.