Schiff bases of (+)/(-)-carvone: influence of chirality on flavour

1999 ◽  
Vol 208 (5-6) ◽  
pp. 305-307 ◽  
Author(s):  
G. Buchbauer ◽  
J. Höfinghoff ◽  
E. M. Hoffmann
Keyword(s):  
Schiff Bases

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

Preparation and Characterisation of Manganese and Vanadium Complexes of Schiff Bases

2011 ◽  
Vol 4 (1) ◽  
pp. 88-90
Author(s):  
Rahul K Rastogi ◽  
◽  
S. Ahmad S. Ahmad
Keyword(s):  
Schiff Bases ◽  
Vanadium Complexes

SYNTHESIS AND CHARACTERIZATION OF SOME SCHIFF BASES BASED ON 1, 8-DIAMINOOCTANE FOR EVALUATION AS CORROSION INHIBITORS

2018 ◽  
Vol 42 (1) ◽  
pp. 1-29
Author(s):  
Hashem, A. I. ◽  
Ismaeel, H. S. ◽  
Dawood, E. A. ◽  
and El-Mokadem, T. H.
Keyword(s):  
Schiff Bases ◽  
Corrosion Inhibitors ◽  
Synthesis And Characterization

Synthesis, Conformational Analysis, Infrared, Raman and UV-Visible Spectra of Novel Schiff Bases compiled with DFT Calculations

2020 ◽  
Vol 23 (7) ◽  
pp. 568-586
Author(s):  
Samy M. Ahmed ◽  
Ibrahim A. Shaaban ◽  
Elsayed H. El-Mossalamy ◽  
Tarek A. Mohamed
Keyword(s):  
Schiff Bases ◽  
1H Nmr ◽  
Electronic Absorption Spectra ◽  
Chemical Shifts ◽  
Basis Set ◽  
Oh Groups ◽  
Vibrational Assignments ◽  
Cartesian Coordinate ◽  
Surface Scan ◽  
Ir And Raman

Objective: Two novel Schiff bases named, 2-((2-Hydroxybenzylidene)amino)-4,5,6,7- tetrahydrobenzo[b] thiophene-3-carbonitrile (BESB1) and 2-((Furan-2-ylmethylene)amino)-4,5,6, 7-tetrahydro-benzo[b]thiophene-3-carbonitrile (BESB2) were synthesized. Methods: The structures were characterized based on CHN elemental analysis, mid-infrared (400– 4000 cm-1), Raman (100-4000 cm-1), 1H NMR, mass and UV-Vis spectroscopic measurements. In addition, quantum mechanical calculations using DFT-B3LYP method at 6-31G(d) basis set were carried out for both Schiff bases. Initially, we have carried out complete geometry optimizations followed by frequency calculations for the proposed conformational isomers; BESB1 (A–E) and BESB2 (F–J) based on the orientations of both CN and OH groups against the azomethine lonepair (NLP) in addition to the 3D assumption. Results: The computational outcomes favor conformer A for BESB1 in which the C≡N and OH moieties are cis towards the NLP while conformer G is preferred for BESB2 (the C≡N/furan-O are cis/trans towards the NLP) which was found consistent with the results of relaxed potential energy surface scan. Aided by normal coordinate analysis of the Cartesian coordinate displacements, we have suggested reliable vibrational assignments for all observed IR and Raman bands. Moreover, the electronic absorption spectra for the favored conformers were predicted in DMSO solution using TD-B3LYP/6-31G(d) calculations. Similarly, the 1H NMR chemical shifts were also estimated using GIAO approach implementing PCM including solvent effects (DMSO-d6). Conclusion: Proper interpretations of the observed electronic transition, chemical shifts, IR and Raman bands were presented in this study.

Synthesis, Characterization, Anti-proliferative Evaluation, and DNA Flow Cytometry Analysis of Some 2-Thiohydantoin Derivatives

2020 ◽  
Vol 20 (18) ◽  
pp. 1929-1941
Author(s):  
Heba A. Elhady ◽  
Hossa F. Al-Shareef
Keyword(s):  
Anticancer Activity ◽  
Schiff Bases ◽  
Anticancer Agents ◽  
Proliferative Activity ◽  
Cancer Cell Line ◽  
Aromatic Aldehydes ◽  
Pharmaceutical Chemistry ◽  
Dna Flow Cytometry ◽  
Quinazoline Derivative ◽  
Reference Drug

Background and Objective: Due to the well-documented anti-proliferative activity of 2-thiohydantoin incorporated with pyrazole, oxadiazole, quinazoline, urea, β-naphthyl carbamate and Schiff bases, they are noteworthy in pharmaceutical chemistry. Methods: An efficient approach for the synthesis of a novel series of 2-thiohydantoin derivatives incorporated with pyrazole and oxadiazole has proceeded via the reaction of the acyl hydrazide with chalcones and/or triethyl orthoformate. Schiff bases were synthesized by the reaction of the acyl hydrazide with different aromatic aldehydes. Moreover, Curtius rearrangement was applied to the acyl azide to obtain the urea derivative, quinazoline derivative, and carbamate derivative. Results: The synthesized compounds structures were discussed and confirmed depending on their spectral data. The anticancer activity of these heterocyclic compounds was evaluated against the breast cancer cell line (MCF-7), where they showed variable activity. Compound 5d found to have a superior anticancer activity, where it has (IC50 = 2.07 ± 0.13 μg/mL) in comparison with the reference drug doxorubicin that has (IC50 = 2.79 ± 0.07 μg / mL). Then compound 5d subjected to further studies such as cell cycle analysis and apoptosis. Apoptosis was confirmed by the upregulation of Bax, downregulation of Bcl-2, and the increase of the caspase 3/7percentage. Conclusion: Insertion of pyrazole, oxadiazole and, quinazoline moieties with 2-thiohydantoin moiety led to the enhancement of its anti-proliferative activity. Hence they can be used as anticancer agents.

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