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1.
J Org Chem ; 83(15): 8401-8409, 2018 08 03.
Article in English | MEDLINE | ID: mdl-29979590

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.

2.
ACS Omega ; 2(12): 8633-8639, 2017 Dec 31.
Article in English | MEDLINE | ID: mdl-30023588

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.

3.
Dalton Trans ; 44(26): 11805-10, 2015 Jul 14.
Article in English | MEDLINE | ID: mdl-26051708

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/methods
4.
Org Biomol Chem ; 12(19): 3037-44, 2014 May 21.
Article in English | MEDLINE | ID: mdl-24671378

ABSTRACT

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, Ultraviolet
5.
Chem Commun (Camb) ; 49(99): 11656-8, 2013 Dec 25.
Article in English | MEDLINE | ID: mdl-24185489

ABSTRACT

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/methods
6.
Dalton Trans ; 42(36): 12844-8, 2013 Sep 28.
Article in English | MEDLINE | ID: mdl-23900587

ABSTRACT

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, Fluorescence
7.
Dalton Trans ; 42(30): 10682-6, 2013 Aug 14.
Article in English | MEDLINE | ID: mdl-23788230

ABSTRACT

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).

8.
Dalton Trans ; 42(28): 10097-101, 2013 Jul 28.
Article in English | MEDLINE | ID: mdl-23732748

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-Reduction
9.
Dalton Trans ; 42(22): 8078-85, 2013 Jun 14.
Article in English | MEDLINE | ID: mdl-23575906

ABSTRACT

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 Specificity
10.
Chem Commun (Camb) ; 49(28): 2912-4, 2013 Apr 11.
Article in English | MEDLINE | ID: mdl-23450121

ABSTRACT

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.

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