Showing papers on "Pyrazoline published in 2012"

Synthesis of new 4-thiazolidinone-, pyrazoline-, and isatin-based conjugates with promising antitumor activity.

Abstract: The synthesis and antitumor activity screening of novel 3-[2-(3,5-diaryl-4,5-dihydropyrazol-1-yl)-4-oxo-4,5-dihydro-1,3-thiazol-5-ylidene]-2,3-dihydro-1H-indol-2-ones 1–23 and 3-(3,5-diarylpyrazol-...

Synthesis and biological evaluation of chalcone derivatives (mini review).

Abstract: Chalcones are the principal precursors for the biosynthesis of flavonoids and isoflavonoids. A three carbon α, β-unsaturated carbonyl system constitutes chalcones. Chalcones are the condensation products of aromatic aldehyde with acetophenones in attendance of catalyst. They go through an assortment of chemical reactions and are found advantageous in synthesis of pyrazoline, isoxazole and a variety of heterocyclic compounds. In synthesizing a range of therapeutic compounds, chalcones impart key role. They have showed worth mentioning therapeutic efficacy for the treatment of various diseases. Chalcone based derivatives have gained heed since they own simple structures, and diverse pharmacological actions. A lot of methods and schemes have been reported for the synthesis of these compounds. Amongst all, Aldol condensation and Claisen-Schmidt condensation still grasp high up position. Other distinguished techniques include Suzuki reaction, Witting reaction, Friedel-Crafts acylation with cinnamoyl chloride, Photo-Fries rearrangement of phenyl cinnamates etc. These inventive techniques utilize various catalysts and reagents including SOCl(2) natural phosphate, lithium nitrate, amino grafted zeolites, zinc oxide, water, Na(2)CO(3), PEG400, silicasulfuric acid, ZrCl(4) and ionic liquid etc. The development of better techniques for the synthesis of α, β- unsaturated carbonyl compounds is still in high demand. In brief, we have explained the methods and catalysts used in the synthesis of chalcones along with their biological activities in a review form to provide information for the development of new-fangled processes targeting better yield, less reaction time and least side effects with utmost pharmacological properties.

Simple pyrazoline and pyrazole “turn on” fluorescent sensors selective for Cd2+ and Zn2+ in MeCN

Abstract: An efficient two-step synthesis of pyrazoline ligand 1 is described which is an effective “turn on” fluorescent sensor for Cd2+ in MeCN. Oxidation to the corresponding pyrazole ligand 2 creates a “turn on” fluorescent sensor now selective for Zn2+ and able to distinguish it from Cd2+.

A highly sensitive fluorescent probe based on simple pyrazoline for Zn2+ in living neuron cells.

Abstract: We develop a pyrazoline-based fluorescent sensor for biological Zn2+ detection. The sensor shows good binding selectivity for Zn2+ over competing metal with 40-fold fluorescence enhancement in response to Zn2+. The new probe is cell-permeable and can be used to detect intracellular zinc ions in living neuron cells.

Discovery and optimization of pyrazoline derivatives as promising monoamine oxidase inhibitors.

Abstract: Among different heterocyclic chemotypes incorporating two nitrogen atoms, pyrazolines could be considered a valid pharmacophore for the synthesis of selective monoamine oxidase (MAO) inhibitors because they were developed by the cyclization of the early hydrazine derivatives such as isocarboxazid. Substituted pyrazolines, decorated with different functional groups, are important lead compounds endowed with a large amount of biological activities. As a matter of this, most of them were also evaluated as dual inhibitors with a synergistic action towards different classes of enzymes (ciclooxygenase, acetylcholinesterase, butyrylcholinesterase). Moreover due to the direct correlation with the recognized MAO inhibition, this scaffold displayed antidepressant and anticonvulsant properties in animal models.

Synthesis, antimicrobial, antioxidant, anti-inflammatory, and analgesic activities of some new 3-(2′-thienyl)pyrazole-based heterocycles

Abstract: 1-Phenyl-3-(thiophen-2-yl)-1H-pyrazole-4-carbaldehyde was used as a synthon for the synthesis of new thiazole and pyrazoline heterocycles having 2-thienylpyrazole moiety. The antimicrobial, anti-inflammatory, and analgesic activities of the synthesized compounds were evaluated using agar diffusion method, carrageenan-induced paw edema, and writhing assays, respectively. It was found that the majority of the tested compounds exhibited both analgesic and anti-inflammatory activities.

Synthesis, Characterization and Antimicrobial Activities of Some Thiazole Derivatives

Abstract: In this work a series of thiazoles 9a-l were prepared by incorporation of pyrazoline ring at position 2 of 2-hydrazinyl-N-(4-phenylthiazol-2-yl) acetamide 8a-c by treating with chalcones 3a-d. The structures of the newly synthe- sized compounds were determined on the basis of their elemental analyses and spectroscopic data such as IR and HNMR spectra.The antimicrobial activity of isolated heterocyclic compounds was evaluated against Gram-positive, Gram-negative bacteria and fungi. Most of the compounds showed a moderate degree of potent antimicrobial activity.

Synthesis and antiviral activity of new 3-methyl-1,5-diphenyl-1H-pyrazole derivatives

Abstract: A new series of 4-substituted 3-methyl-1,5-diphenyl-1H-pyrazoles 4–11 has been synthesized and evaluated for its in vitro antiviral activity and cytotoxicity against herpes simplex virus type-1 grown on Vero African green monkey kidney cells through plaque-reduction assay method using acyclovir as a positive control. The synthesis was achieved through Claisen-Schmidt condensation reaction of 3-methyl-1,5-diphenyl-1H-pyrazole-4-carbaldehyde (3) with acetophenone derivatives to give various enones 4a–f which are considered an important synthon for the construction of different heterocyclic rings as isoxazoline, pyrazoline, pyrimidine, pyridine, and fused pyridine via several synthetic routes. Biological evaluation of the prepared compounds showed that 3-(4-methylphenyl)-5-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)-4,5-dihydroisoxazole (5f), 6-(4-methylphenyl)-N-[(3-(methylsulfanyl)phenyl)]-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)pyrimidin-2-amine (7), 6-(4-bromophenyl)-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl)-2-oxo-1,2-dihydropyridine-3-carbonitrile (8), and 2-amino-6-(4-bromophenyl)-4-(3-methyl-1,5-diphenyl-1H-pyrazol-4-yl) pyridine-3-carbonitrile (9) exhibited strong antiviral activity with IC50 (0.02, 0.04, 0.03, 0.03), respectively, compared to the used reference drug. The synthesized compounds were characterized by physical constants and the structures of the title compounds were confirmed by IR, 1H NMR, mass spectra, and elemental analyses.

Explicit spectral response of the geometrical isomers of a bio-active pyrazoline derivative encapsulated in β-cyclodextrin nanocavity: a photophysical and quantum chemical analysis.

Abstract: The existence of two geometrical isomers (cis- and trans-) of a biologically significant pyrazoline derivative [5-(-1′-(4-bromo-phenyl)-3a′,7a′-hexahydro-1′H-indazol-3′-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile] (PZ) has been established using a combined theoretical and experimental investigation. Solvatochromic analysis of PZ revealed the existence of said cis- and trans- isomers. The unique solvatochromic response of the PZ isomers and their preferential encapsulation within β-cyclodextrin (β-CD) nanocavity clearly shows the difference in the behavioral nature of the isomers of PZ in homogeneous and heterogeneous medium. Solvent polarity, time-resolved study, and anisotropy results also reinforce in favor of the existence of the isomers. To evaluate the actual orientation of cis and trans-PZ, the ground and excited state geometry of these isomers were optimized by the DFT/LanL2DZ and CIS/LanL2DZ methods, respectively. The experimentally observed results and the theoretically calculated results ar...

Synthesis and biological evaluation of novel pyrazoline derivatives as anti-inflammatory and antioxidant agents

Abstract: A series of novel 5-aryl-3-cyclopropyl-4,5-dihydropyrazole derivatives 2a–p were synthesized via cyclization of chalcones 1a–h with thiosemicarbazide or semicarbazide HCl and evaluated as anti-inflammatory/antioxidant agents. The structures were confirmed by elemental analyses and spectral data. The free radical scavenging activity toward superoxide was determined. Their effect on hepatocytes viability and nitric oxide (NO) production in LPS-stimulated macrophages was also determined. The results showed that compounds 2e and 2n demonstrated the highest free-radical scavenging and anti-inflammatory activities, thus can be useful in the prevention of oxidative stress and inflammation-related disorders.

Synthesis and in vitro antifungal evaluation of 1,3,5-trisubstituted-2-pyrazoline derivatives.

Abstract: Pyrazolines, the well-known five-membered nitrogen-containing heterocyclic compounds, have received considerable interests in the fields of medicinal and agricultural chemistry because of their broad spectrum of biological activities. To discover more potent antifungal compounds, a series of structurally related 1,3,5-trisubstituted-2-pyrazoline derivatives have been synthesized by introducing furan rings regarded as bioactive substructure into the scaffold of pyrazolines and tested for their activities against six plant pathogenic fungi in vitro. The preliminary bioassays indicated that almost all synthesized compounds had displayed variable growth inhibitory effects on the tested pathogenic fungi. In particular, compounds 4, 7, 9, 12, 18, 19, and 38 displayed excellent antifungal activities against Rhizoctonia solani and their inhibition of growth reached 100% at the concentration of 20 mg/L. Additionally, compounds 9 and 19 bearing two furan rings, respectively, at site 3 and site 5 of the pyrazoline cycle showed the strongest activities against R. solani (the EC50 were 3.46 mg/L and 3.20 mg/L). The bioactivity results provide good starting templates for further structural optimization of pyrazoline derivatives.

Synthesis and selective inhibitory activity against human COX-1 of novel 1-(4-substituted-thiazol-2-yl)-3,5-di(hetero)aryl-pyrazoline derivatives.

Abstract: Novel 1-(4-ethyl carboxylate-thiazol-2-yl)-3,5-di(hetero)aryl-2-pyrazoline derivatives were obtained by reacting 3,5-di(hetero)aryl-1-thiocarbamoyl-2-pyrazolines with the ethyl ester of α-bromo-pyruvic acid. The synthesized compounds were confirmed by spectroscopic data and assayed to evaluate their in vitro ability to inhibit both isoforms of human cyclooxygenase (hCOX). Some derivatives (compounds 5, 6, 13, 16, and 17) displayed promising selectivity against hCOX-1 in the micromolar range and were shown to have a selectivity index similar or better than the reference drugs (indometacin, diclofenac). The introduction of a phenyl or a 4-F-phenyl ring on the C5 associated with a 4-substituted phenyl or a heteroaryl group on the C3 of (4-substituted-thiazol-2-yl)pyrazoline derivatives improved the activity against hCOX-1. Thanks to these preliminary results it could be possible to extend our knowledge of the pharmacophoric requirements for the discovery of new pyrazoline-based hCOX-1 inhibitors.

Synthesis of 1,3,5-trisubstituted pyrazoline nucleus containing compounds and screening for antimicrobial activity

Abstract: In this study, a novel series of heterocyclic compounds containing pyrazoline nucleus has been synthesized. The compounds were synthesized in two steps. Chalcone was synthesized in the first step by Claisen-Schmidt reaction, using 1-acetylnaphthalene and p-nitro benzaldehyde as reactants. In the second step, the chalcone was cyclized in an acidic medium with some hydrazine derivatives to form pyrazolines. All the compounds were characterized by physical, chromatographic, spectroscopic, and elemental analysis and evaluated in vitro for antimicrobial activity against nine microorganisms by cup-plate method. The minimum inhibitory concentration of all the compounds was determined by tube dilution method. All the compounds exhibited higher antibacterial activity as compared to the antifungal activity. Compound 5g (3-Naphthalen-1-yl-1-(2-nitro-phenyl)-5-(4-nitro-phenyl)-4,5-dihydro-1H-pyrazole) exhibited maximum antibacterial and antifungal activity and may be designated as the most potent member of the series, with 2-nitrophenyl group at N-1 position of the 2-pyrazoline ring.

Synthesis and Antibacterial Activity of Some Novel Chalcones, Pyrazoline and 3- Cyanopyridine Derivatives Based on Khellinone as well as Ni(II), Co(II) and Zn(II) Complexes

Abstract: Chalcones 3a-d were synthesized by condensing khellinone 1 with aryl aldehydes 2a-d. Chalcones 3a-c reacted with hydrazine hydrate in ethanol or in glacial acetic acid to afford 1H- pyrazolines 4a-c or N-acetylpyrazolines 5a-c, respectively. N-phenylpyrazolines 6a,b were synthesized by reaction of chalcones 3a,b with phenyl hydrazine in ethanol. When 3b was refluxed in ethanol containing piperidine, it yielded 4,9-dimethoxy-7-(naphth-1-yl)-6,7-dihydro-5H-furo(3,2-g)chromen-5- one 7. Moreover, Chalcone 3c reacted with 2-cyanoacetamide or 2-cyanothioacetamide in ethanol to afford 3-cyanopyridines 8a and 8b respectively. The structure of the synthesized compounds was established based on elemental analysis and spectral data. The metal complexes 9, 10 and 11 of chalcone 3c; (L) with (Ni(II), Co(II) and Zn(II)) respectively, were synthesized and characterized by IR, 1 H NMR, electronic absorption, magnetic susceptibility, molar conductivity and elemental analysis. The prepared complexes 9-11 had the general structural formula: (M(L)Cl2(H2O)2) where M=Ni(II), Co(II) or Zn(II) and L=3c. In order to study the structure-activity relationship, representative compounds of the synthesized products beside the metal complexes were screened for their antibacterial activities. The results indicated that some synthesized compounds had antibacterial activity as well as the metal complexes 9, 10 and 11 exhibited moderate antibacterial activities while the free ligand 3c; (L) had no activity.

Synthesis and evaluation of DPPH and anti-inflammatory activities of 2,6-bisbenzylidenecyclohexanone and pyrazoline derivatives

Abstract: A series of thirty three 2,6-bisbenzylidenecyclohexanone and pyrazoline derivatives were synthesized and evaluated for inhibitory activities on IFN-γ/LPS-activated RAW 264.7 cells and DPPH radical scavenging activity. Compounds 8, 9, and 11a demonstrated significant NO inhibitory activity as compared to L-NAME and curcumin with IC50 values of 6.68 ± 0.16, 6.09 ± 0.46, and 6.84 ± 0.12 μM, respectively. Apparently the suppression upon NO secretion was not due to cell death since the active compounds did not reduce the cell viability in close proximity to the IC50 of NO inhibition. Overall, incorporation of pyrazoline ring as part of the linker chain improved cell viability compared to the 2,6-bisbenzylidenecyclohexanone derivatives. Meanwhile, compound 11 (IC50 = 13.27 ± 1.78 μM) bearing ortho hydroxyls on the aromatic rings recorded the highest radical scavenging activity as compared with quercetin (IC50 = 21.46 ± 0.85 μM).