scholarly journals Revisiting salicylidene-based anion receptors

RSC Advances ◽  
2021 ◽  
Vol 11 (58) ◽  
pp. 36850-36858
Author(s):  
Sandeep Kumar Dey ◽  
Sonam Kumari ◽  
Sonal Mandrekar ◽  
Shashank N. Mhaldar ◽  
Sarvesh S. Harmalkar ◽  
...  
Keyword(s):  
Schiff Bases ◽  
Anion Receptors ◽  
Anion Sensors ◽  
Oxo Anions ◽  
Imine Bond

Salicylidene Schiff bases undergo imine bond hydrolysis in the presence of halides and oxo-anions in aprotic media, raising fundamental questions on the applicability of salicylidene-based receptors as anion sensors.

scholarly journals 4-Aminobenzoic Acid Derivatives: Converting Folate Precursor to Antimicrobial and Cytotoxic Agents

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 9 ◽  
Author(s):  
Martin Krátký ◽  
Klára Konečná ◽  
Jiří Janoušek ◽  
Michaela Brablíková ◽  
Ondřej Janďourek ◽  
...  
Keyword(s):  
Schiff Bases ◽  
Biological Activities ◽  
Aromatic Aldehydes ◽  
Antimycobacterial Activity ◽  
Cytotoxic Agents ◽  
Aminobenzoic Acid ◽  
Human Pathogens ◽  
Essential Nutrient ◽  
One Step ◽  
Imine Bond

4-aminobenzoic acid (PABA), an essential nutrient for many human pathogens, but dispensable for humans, and its derivatives have exhibited various biological activities. In this study, we combined two pharmacophores using a molecular hybridization approach: this vitamin-like molecule and various aromatic aldehydes, including salicylaldehydes and 5-nitrofurfural, via imine bond in one-step reaction. Resulting Schiff bases were screened as potential antimicrobial and cytotoxic agents. The simple chemical modification of non-toxic PABA resulted in constitution of antibacterial activity including inhibition of methicillin-resistant Staphylococcus aureus (minimum inhibitory concentrations, MIC, from 15.62 µM), moderate antimycobacterial activity (MIC ≥ 62.5 µM) and potent broad-spectrum antifungal properties (MIC of ≥ 7.81 µM). Some of the Schiff bases also exhibited notable cytotoxicity for cancer HepG2 cell line (IC50 ≥ 15.0 µM). Regarding aldehyde used for the derivatization of PABA, it is possible to tune up the particular activities and obtain derivatives with promising bioactivities.

Sensing anions on surfaces: tethering triazolium based anion receptors to polymer resins

RSC Advances ◽  
2016 ◽  
Vol 6 (40) ◽  
pp. 33880-33887 ◽  
Author(s):  
S. Byrne ◽  
K. M. Mullen
Keyword(s):  
Chemical Reactivity ◽  
Mas Nmr ◽  
Anion Binding ◽  
Anion Receptors ◽  
Surface Characterisation ◽  
Binding Properties ◽  
Good Surface ◽  
Anion Sensors ◽  
Characterisation Techniques

Herein we report the development of a new series of surface bound triazolium based anion sensors. Differences in the chemical reactivity and anion binding properties were observed; highlighting the need for good surface characterisation techniques such as HR MAS NMR.

scholarly journals Carbazole-Based Colorimetric Anion Sensors

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3205
Author(s):  
Krystyna Maslowska-Jarzyna ◽  
Maria L. Korczak ◽  
Jakub A. Wagner ◽  
Michał J. Chmielewski
Keyword(s):  
Hydrogen Bond ◽  
Visible Region ◽  
Building Blocks ◽  
Anion Transport ◽  
Anion Binding ◽  
Anion Receptors ◽  
Binding Studies ◽  
Anion Sensor ◽  
Anion Sensors ◽  
Anion Interaction

Owing to their strong carbazole chromophore and fluorophore, as well as to their powerful and convergent hydrogen bond donors, 1,8-diaminocarbazoles are amongst the most attractive and synthetically versatile building blocks for the construction of anion receptors, sensors, and transporters. Aiming to develop carbazole-based colorimetric anion sensors, herein we describe the synthesis of 1,8-diaminocarbazoles substituted with strongly electron-withdrawing substituents, i.e., 3,6-dicyano and 3,6-dinitro. Both of these precursors were subsequently converted into model diamide receptors. Anion binding studies revealed that the new receptors exhibited significantly enhanced anion affinities, but also significantly increased acidities. We also found that rear substitution of 1,8-diamidocarbazole with two nitro groups shifted its absorption spectrum into the visible region and converted the receptor into a colorimetric anion sensor. The new sensor displayed vivid color and fluorescence changes upon addition of basic anions in wet dimethyl sulfoxide, but it was poorly selective; because of its enhanced acidity, the dominant receptor-anion interaction for most anions was proton transfer and, accordingly, similar changes in color were observed for all basic anions. The highly acidic and strongly binding receptors developed in this study may be applicable in organocatalysis or in pH-switchable anion transport through lipophilic membranes.

scholarly journals Synthesis, characterization and evaluation of antidengue activity of enantiomeric Schiff bases derived from S-substituted dithiocarbazate

2020 ◽  
Vol 44 (5) ◽  
pp. 1395-1409
Author(s):  
Maqsood MARYAM ◽  
Sang Loon TAN ◽  
Karen Ann CROUSE ◽  
Mohamed Ibrahim MOHAMED TAHIR ◽  
Hui-Yee CHEE
Keyword(s):  
Antiviral Activity ◽  
Schiff Bases ◽  
Cytopathic Effect ◽  
Vero Cells ◽  
Enantiomerically Pure ◽  
Reduction Assay ◽  
Acid Catalyzed ◽  
Imine Bond ◽  
Unit Reduction

A series of Schiff bases have been successfully synthesized through the acid-catalyzed condensation of S-substituted dithiocarbazates and three enantiomerically pure monoterpenes, (1R)-(+)-camphor, (1S)-(-)-camphor, (1R)-(-)-camphorquinone, (1S)- (+)-camphorquinone, (R)-(-)-carvone and (S)-(+)-carvone. Spectroscopic results revealed that the Schiff bases containing camphor or carvone likely adopted an E-configuration along the characteristic imine bond while those containing camphorquinone assumed a Z-configuration. The antidengue potential of these compounds was evaluated based on DENV 2 caused cytopathic effect (CPE) reduction-based in vitro evaluation. The compounds were validated through secondary foci forming unit reduction assay (FFURA). Compounds were also tested for their cytotoxicity against Vero cells. The compounds showed variable degrees of antiviral activity with the camphor compounds displaying the highest antidengue potential. The enantiomers of the compounds behaved almost similarly during the antiviral evaluation.

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

2018 ◽  
Vol 7 (6) ◽  
Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.
Keyword(s):  
Antimicrobial Activity ◽  
Spectral Analysis ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Biological Evaluation ◽  
Fungal Strain ◽  
Bacterial Strains ◽  
Standard Drug ◽  
Gram Negative ◽  
E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

Protonation Studies of Schiff Bases Using 13C and 15N-NMR Spectroscopy

2006 ◽  
Author(s):  
Almudena Perona ◽  
Dionisia Sanz ◽  
Rosa Claramunt ◽  
Elena Pinilla ◽  
M. Torres ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Schiff Bases
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