Yahia N. Mabkhot

Zwitterionic pyrimidinium adducts as antioxidants with therapeutic potential as nitric oxide scavenger

A variety of zwitterionic adducts were synthesized by using means green chemistry method. The products contain the biologically active barbituric acid moiety embedded in zwitterion products. Both features are pharmaceutically relevant. The chemical structures were deduced by (1)H-, (13)C-, NMR and HRMS spectral analysis, and X-ray diffraction techniques. In vitro evaluation for the antioxidant activities were carried out towards the inhibition of nitric oxide (NO) radical, known to regulate a mechanism of signals for various cellular functions. NO also play an important role as a mediator of various pathological conditions responsible for cellular damages such as strokes, cancers, diabetes, chronic heart failure and inflammatory disease and various neurodegenerative disorders. All tested compounds were found to be more potent nitric oxide scavengers as compared to standard drug ascorbic acid (IC50 = 618 ± 2.0 μM). Compounds 4c and e exhibiting several hundred fold more activity against nitric oxide radical with IC50 values of 69 ± 1.66 and 70.1 ± 0.89 μM respectively, as compared to standard drug ascorbic acid (IC50 = 618 ± 2.0 μM).

Tandem Aldol-Michael Reactions in Aqueous Diethylamine Medium: A Greener and Efficient Approach to Bis-Pyrimidine Derivatives

A simple protocol, involving the green synthesis for the construction of novel bis-pyrimidine derivatives, 3a–i and 4a–e are accomplished by the aqueous diethylamine media promoted tandem Aldol-Michael reaction between two molecules of barbituric acid derivatives 1a,b with various aldehydes. This efficient synthetic protocol using an economic and environmentally friendly reaction media with versatility and shorter reaction time provides bis-pyrimidine derivatives with high yields (88%–99%).

Synthesis, reactions and biological activity of some new bis-heterocyclic ring compounds containing sulphur atom

BackgroundThe derivatives of thieno[2,3-b]thiophene belong to a significant category of heterocyclic compounds, which have shown a wide spectrum of medical and industrial application.ResultsA new building block with two electrophilic center of thieno[2,3-b]thiophene derivatives 2 has been reported by one-pot reaction of diketone derivative 1 with Br2/AcOH in excellent yield. A variety of heteroaromatics having bis(1H-imidazo[1,2a] benzimidazole), bis(1H-imidazo[1,2-b][1,2,4]triazole)-3-methyl-4-phenylthieno[2,3-b]thiophene derivatives, dioxazolo-, dithiazolo-, and 1H-imidazolo-3-methyl-4-phenylthieno[2,3-b]thiophene derivatives as well pyrrolo, thiazolo -3-methyl-4-phenylthieno[2,3-b]thiophene derivatives have been designed, synthesized, characterized, and evaluated for their biological activity. Compounds 3–9 showed good bioassay result. These new derivatives were evaluated for anti-cancer activity against PC-3 cell lines, in vitro antioxidant potential and β-glucuronidase and α-glucosidase inhibitory activities. Compound 3 (IC50 = 56.26 ± 3.18 μM) showed a potent DPPH radical scavenging antioxidant activity and found to be more active than standard N-acetylcystein (IC50 = 105.9 ± 1.1 μM). Compounds 8a (IC50 = 13.2 ± 0.34 μM) and 8b (IC50 = 14.1 ± 0.28 μM) found as potent inhibitor of α-glucusidase several fold more active than the standard acarbose (IC50 = 841 ± 1.73 μM). Most promising results were obtained in β-glucuronidase enzyme inhibition assay. Compounds 5 (IC50 = 0.13 ± 0.019 μM), 6 (IC50 = 19.9 ± 0.285 μM), 8a (IC50 = 1.2 ± 0.0785 μM) and 9 (IC50 = 0.003 ± 0.09 μM) showed a potent inhibition of β-glucuronidase. Compound 9 was found to be several hundred fold more active than standard D-Saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 μM).ConclusionsSynthesis, characterization, and in vitro biological activity of a series of thieno[2,3-b]thiophene have been investigated.

Facile and Convenient Synthesis of New Thieno[2,3-b]-Thiophene Derivatives

A facile and convenient synthesis of bis(2-(1H-benzo[d]imidazol-2(3H)-ylidene)-3-oxopropanenitrile), bis((3-amino-5-(methylthio)-1H-pyrazol-4-yl)methanone) and bis(2-thioxo-1,2-dihydropyrimidine-5-carbonitrile) derivatives incorporating a thieno- [2,3-b]thiophene moiety via versatile, readily accessible diethyl 3,4-dimethylthieno-[2,3-b]thiophene-2,5-dicarboxylate (1) is described.

SYNTHESIS AND ANTIMICROBIAL EVALUATION OF NEW PYRAZOLE, THIOPHENE, THIAZOLE AND 1,3,4-THIADIAZOLE DERIVATIVES INCORPORATING PYRIMIDINE RING

The utility of 3-oxo-N-(pyrimidin-2-yl)butanamide (1) in the synthesis of some new pyrazole, thiophene, thiazole, and 1,3,4-thiadiazole derivatives pendant to a pyrimidine ring is reported. Antimicrobial evaluation of some selected examples from the synthesized products was carried out and showed moderate activity.

Organically Modified Silica with Pyrazole-3-carbaldehyde as a New Sorbent for Solid-Liquid Extraction of Heavy Metals

A new chelating matrix, SiNP, has been prepared by immobilizing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel modified with 3-aminopropyl-trimethoxysilane. This new chelating material was well characterized by elemental analysis, FT-IR spectroscopy, cross polarization magic angle spinning solid state 13C-NMR, nitrogen adsorption-desorption isotherm, BET surface area, BJH pore size, and scanning electron microscopy (SEM). The new product exhibits good chemical and thermal stability as determined by thermogravimetry curves (TGA). The new prepared material was used as an adsorbent for the solid-phase extraction (SPE) of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions using a batch method, prior to their determination by flame atomic adsorption spectrometry. The adsorption capacity was investigated using kinetics and pH effects. Common coexisting ions did not interfere with separation and determination.

Facile and Convenient Synthesis of Pyrazole, Pyridine, Pyridazine, Pyrazolo[3,4-b]pyridine, and Pyrazolo[5,1-c][1,2,4]triazine Derivatives

Abstract A convenient synthesis of a series of pyrazole, pyridine, pyridinethione, pyridazine, pyrazolo[3,4-b]pyridine, imidazo[1,2-a]pyrimidine, and pyrazolo[5,1-c][1 2 4]triazine derivatives incorporating a pyrimidine moiety, via the reactions of the versatile, readily accessible 3-oxo-N-(pyrimid-2-yl)butanamide with the appropriate reagents, is described.

SYNTHESIS AND ANTIMICROBIAL EVALUATION OF SOME NEW PYRIMIDINE DERIVATIVES

The utility of ethyl 6-methyl-2-oxo-4-phenyl-1,2-dihydropyrimidine-5-carboxylate (1) in the synthesis of some new pyrido[1,2-f]pyrimidine, pyrazolo-[3,4-b]pyrido[1,2-/]pyrimidine, 6-(4-substituted styryl)pyrimidine, pyrido[4,3-d]-pyrimidine, pynmido[5,4-d]pyridazine and substituted-6-(thien-2-yl)pyrimidine derivatives is reported. Antimicrobial evaluation of some selected examples from the synthesized products was carried out.

An efficient and green procedure for synthesis of rhodanine derivatives by aldol-thia-Michael protocol using aqueous diethylamine medium

A simple, economical, and green approach to the synthesis of rhodanine derivatives using a tandem aldol condensation-thia-Michael addition process in aqueous diethylamine medium was described. The experiment protocol features simple operations, and the products were isolated in high to excellent yields (82–96%). As spontaneous precipitation always occurs at the end of the process, this leads to easy separation of the products via a simple filtration.

Synthesis of Thieno[2,3-b]thiophene Containing Bis-Heterocycles-Novel Pharmacophores

Thioenethiophene derivatives represent an important class of compounds with diverse biological activities. We describe here the synthesis of a new series of thieno[2,3-b]thiophene containing bis-heterocyclic compounds 3–7. All the compounds were evaluated for their in vitro antioxidant potential, α-glucosidase and β-glucuronidase inhibiton and anticancer activity against PC-3 cell lines. Compounds 2b (IC50 = 1.3 ± 0.2 μM), 5a (IC50 = 2.3 ± 0.4 μM) and 5b (IC50 = 8.7 ± 0.1 μM) showed a potent inhibition of β-glucuronidase enzyme, more active than the standard d-saccharic acid 1,4-lactone (IC50 = 45.8 ± 2.5 μM). Compounds 5a (IC50 = 22.0 ± 0.3 μM) and 5b (IC50 = 58.4 ± 1.2 μM) were also found to be potent α-glucosidase inhibitors as compared to standard drug (acarbose, IC50 = 841 ± 1.7 μM).