Showing papers on "Pyrazole published in 2011"
TL;DR: A detailed review of the synthesis and magnetic properties of structurally characterized iron(II) spin crossover (SCO) active complexes of pyrazole-and pyrazolate-based ligands is given in this article.
247 citations
TL;DR: The phenothiazine core is revealed to be very potent pharmacophoric moiety which can be a rich source of new compounds having desirable biological activities.
228 citations
TL;DR: The direct oxidative coupling of phenylazoles with internal alkynes proceeds efficiently in the presence of a rhodium catalyst and a copper oxidant accompanied by double or quadruple C-H bond cleavages.
Abstract: The direct oxidative coupling of phenylazoles with internal alkynes proceeds efficiently in the presence of a rhodium catalyst and a copper oxidant accompanied by double or quadruple C−H bond cleavages. Thus, as a representative example, 4,5-diphenylpyrazolo[1,5-a]quinoline, 1-(1,2,3,4-tetraphenylnaphthalen-5-yl)pyrazole, and 1-(1,2,3,4,5,6,7,8-octaphenylanthracen-9-yl)pyrazole can be obtained selectively through the coupling of 1-phenylpyrazole and diphenylacetylene in 1:1, 1:2, and 1:4 manners, respectively. The reactions preferentially take place at the electron-deficient sites on the aromatic substrates. A comparison of reactivities of variously substituted and deuterated substrates sheds light on the mechanism of C−H bond cleavage steps. The reaction pathway is highly dependent on reaction conditions employed, especially on the nature of solvent. The influence of solvation of a key rhodacycle intermediate has been investigated computationally. In addition, some of the condensed aromatic products have...
190 citations
TL;DR: In this article, an efficient four-component synthesis of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles involving ethyl acetoacetate, hydrazine hydrate, malononitrile, and various aldehydes using l -proline (10 ǫ%) in water under mild reaction condition in excellent yields is established.
155 citations
TL;DR: In this paper, γ-alumina is used as an expedient and recyclable catalyst for the synthesis of 6-amino-4-alkyl/aryl-3-methyl-2,4-dihydropyrano[2,3- c ]pyrazole-5-carbonitriles in water via a four-component reaction.
147 citations
TL;DR: New arylhydrazone derivatives and a series of 1,5-diphenyl pyrazoles were designed and synthesized from 1-(4-chlorophenyl)-4,4, 4-trifuorobutane-1,3-dione and investigated in vivo for their anti-inflammatory activities and revealed a similar binding mode to SC-558, a selective COX-2 inhibitor.
137 citations
TL;DR: Thirty-six novel pyrazole derivatives were synthesized and studied their antiproliferative activity in human ovarian adenocarcinoma A2780 cells, human lung carcinoma A549 cells, and murine P388 leukemia cells and further analyses showed that they were all able to induce apoptosis, although to a different extent.
131 citations
TL;DR: This Minireview provides an overview of the chemistry of pyrazole and N-heterocyclic carbene (NHC) complexes bearing an NH group at the β-position to the metal.
Abstract: This Minireview provides an overview of the chemistry of pyrazole and N-heterocyclic carbene (NHC) complexes bearing an NH group at the β-position to the metal. The synthesis and structures as well as the Bronsted acidic nature of the β-NH group are described in detail. These complexes are attractive candidates for novel metal-ligand cooperative bifunctional catalysts, which would benefit highly effective molecular and energy transformations.
123 citations
TL;DR: Two new series of Hantzsch 1,4-dihydropyridine derivatives containing substituted pyrazole moiety were synthesized by the reaction of 3-aryl-1H-pyrazole-4-carbaldehydes with 1,3-dicarbonylcompounds (ethylacetoacetate and methylaceto acetate) and ammonium acetate and were found to be potent antibacterial and antioxidant agents.
115 citations
TL;DR: Two series of novel imidazole derivatives containing substituted pyrazole moiety (3a-d and 5a-j) were synthesized and compound 3c was found to be potent antimicrobial agent.
107 citations
TL;DR: Crystalline samples of 3(5)-(9-anthryl)pyrazole and its one derivative exhibit interesting piezochromic behaviors with the emission colors differently changing from blue to green and from green to blue, respectively, upon grinding.
TL;DR: A one-pot four component synthesis of pyranopyroles from aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of catalytic amounts of an organocatalyst imidazole in water as medium is described.
TL;DR: The reaction appears to be general for a variety of α,β-alkynic hydrazones and tolerates the presence of aliphatic, aromatic, and ferrocenyl moieties with electron-withdrawing and electron-donating substituents.
Abstract: Synthesis of pyrazoles via electrophilic cyclization of α,β-alkynic hydrazones by copper(I) iodide is described. When treated with copper(I) iodide in the presence of triethylamine in refluxing acetonitrile, α,β-alkynic hydrazones, prepared readily from hydrazines and propargyl aldehydes and ketones, undergo electrophilic cyclization to afford pyrazole derivatives in good to excellent yields. The reaction appears to be general for a variety of α,β-alkynic hydrazones and tolerates the presence of aliphatic, aromatic, and ferrocenyl moieties with electron-withdrawing and electron-donating substituents.
TL;DR: C−−H activation by acetate-assisted cyclometallation of a phenyl group with half-sandwich complexes [{MCl(2)Cp*}(2)] (M=Ir, Rh) and [{RuCl( 2)-(p-cymene)}(2] can be directed by a wide range of nitrogen donor ligands including pyrazole, oxazoline, oxime, imidazole and triazole, and X
Abstract: C−−H activation by acetate-assisted cyclometallation of a phenyl group with half-sandwich complexes [{MCl(2)Cp*}(2)] (M=Ir, Rh) and [{RuCl(2)-(p-cymene)}(2)] can be directed by a wide range of nitrogen donor ligands including pyrazole, oxazoline, oxime, imidazole and triazole, and X-ray structures of a number of complexes are reported. All the ligands tested cyclometallated at iridium, however ruthenium and rhodium fail to cause cyclometallation in some cases. As a result, the nitrogen donors have been categorised based on their reactivity with the three metals used. The relevance of these cyclometallation reactions to catalytic synthesis of carbocycles and heterocycles is discussed.
TL;DR: Diversely substituted pyrazoles, embedded with a variety of functional groups, are important biological agents and a significant amount of research activity has been directed towards this chemical class.
Abstract: Monoamine oxidase plays a significant role in the control of intracellular concentration of monoaminergic neurotransmitters or neuromodulators and dietary amines. The rapid degradation of these molecules ensures the proper functioning of synaptic neurotransmission and is critically important for the regulation of emotional and other brain functions. The development of human MAO inhibitors led to important breakthroughs in the therapy of several neuropsychiatric disorders. Different families of heterocycles containing 2 or 4 nitrogen atoms have been used as scaffolds for synthesizing selective monoamine oxidase inhibitors, but the early period of the MAO-inhibitors started with hydrazine derivatives. Pyrazole, pyrazoline, and pyrazolidine derivatives can be considered as a cyclic hydrazine moiety. This scaffold also displayed promising antidepressant and anticonvulsant properties as demonstrated by different and established animal models. Diversely substituted pyrazoles, embedded with a variety of functional groups, are important biological agents and a significant amount of research activity has been directed towards this chemical class.
TL;DR: The results showed that the pyrazoline derivative is better at inhibiting growth of both types of bacteria (Gram-positive and Gram-negative) compared to chloramphenicol.
Abstract: A chalcone was prepared by the reaction of terephthalaldehyde with 3-acetyl-2,5-dimethylthiophene. Treatment of this chalcone with thiosemicarbazide/phenyl hydrazine/guanidine hydrochloride/thiourea afforded the corresponding pyrazoline, pyrazole, and pyrimidine in good yields. All the new compounds have been characterized by IR, 1H-NMR, 13C-NMR, GC-MS and elemental analyses. The anti-bacterial activity of these compounds were first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined with the reference of standard drug chloramphenicol. The results showed that the pyrazoline derivative is better at inhibiting growth of both types of bacteria (Gram-positive and Gram-negative) compared to chloramphenicol.
TL;DR: Probes/inhibitors 2b, 3a, 3c, and 3f exerted the antiproliferative and neuroprotective activities at micromolar concentrations through inhibition of nuclear HDACs, indicating that they are cell permeable and the presence of an azide or a diazide group does not interfere with the neuroprotection properties, or enhance cellular cytotoxicity, or affect cell permeability.
Abstract: The design, synthesis, docking, and biological evaluation of novel potent HDAC3 and HDAC8 isoxazole- and pyrazole-based diazide probes suitable for Binding Ensemble Profiling with Photoaffinity Labeling (BEProFL) experiments in cells is described. Both the isoxazole- and pyrazole-based probes exhibit low nanomolar inhibitory activity against HDAC3 and HDAC8, respectively. The pyrazole-based probe 3f appears to be one of the most active HDAC8 inhibitors reported in the literature with an IC50 of 17 nM. Our docking studies suggest that unlike the isoxazole-based ligands the pyrazole-based ligands are flexible enough to occupy the second binding site of HDAC8. Probes/inhibitors 2b, 3a, 3c, and 3f exerted the anti-proliferative and neuroprotective activities at micromolar concentrations through inhibition of nuclear HDACs, indicating that they are cell permeable and the presence of an azide or a diazide group does not interfere with the neuroprotection properties, or enhance cellular cytotoxicity, or affect cell permeability.
TL;DR: Novel methyl 1-tert-butyl-1-pyrazol-3-yl)-2-(aryl)-1H-benzo[d]imidazole-5-carboxylates 11 were synthesized by following a four-step strategy involving a nucleophilic aromatic displacement (S(N)Ar) and a solvent free approach as key steps for the formation of the desired products.
TL;DR: Cytotoxicity assays revealed that the platinacycle 4c exhibits a higher toxicity than cisplatin in the three human cell lines and that the complex 2a presents a remarkable cytotoxicity and selectivity in lung versus breast cancer cell lines (IC(50)>20 μM).
Patent•
15 Dec 2011
TL;DR: In this article, the authors describe methods and use of these mixtures for combating insects, arachnids or nematodes in and on plants, and for protecting such plants being infested with pests, especially also for protecting plant propagation material as like seeds.
Abstract: The present invention relates to pesticidal mixtures comprising as active compounds 1) at least one pyrazole compound I of formula I wherein the variables are as defined in the description; and 2) at least one active compound II as defined in the description in synergistically effective amounts, further to methods and use of these mixtures for combating insects, arachnids or nematodes in and on plants, and for protecting such plants being infested with pests, especially also for protecting plant propagation material as like seeds.
TL;DR: In this paper, a four-component reaction of hydrazine hydrate or phenyl hydrazines, ethyl 3-alkyl-3-oxo propanoate, aldehydes and malononitrile has been achieved in the presence of nanosized magnesium oxide as a highly effective heterogeneous base catalyst.
TL;DR: A triazole compound, C46H46N10O2S2, has been synthesized, and the crystal structure was determined by a single crystal X-ray diffraction study as mentioned in this paper.
Abstract: A new triazole compound, C46H46N10O2S2, has been synthesized, and the crystal structure was determined by a single crystal X-ray diffraction study. The fungicidal activity of the title compound was determined, and the results showed that it displays moderate fungicidal activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT
TL;DR: Through an "interrupted" version of the above reaction, carbonylated spiropyrazoline phosphonates have been synthesized from arylidenecycloalkanones under similar conditions (K(2)CO(3)/EtOH) with absolute regio- and diastereoselectivity.
Abstract: Novel carbonylated pyrazole phosphonates have been synthesized as single regioisomers by treating conjugated enones, dienones, tropone, and quinone with the Bestmann–Ohira reagent under KOH/EtOH conditions at room temperature. Through an “interrupted” version of the above reaction, carbonylated spiropyrazoline phosphonates have been synthesized from arylidenecycloalkanones under similar conditions (K2CO3/EtOH) with absolute regio- and diastereoselectivity. The key structures were confirmed by detailed spectroscopic analysis and X-ray crystallography.
TL;DR: The antitumor activity of the new compounds was accompanied by significant increase in the activity of superoxide dismutase with concomitant decrease in the activities of catalase and glutathione peroxidase and reduced glutATHione level, which allowed reactive oxygen species (ROS)-mediated tumor cells death.
TL;DR: It has been found that the introduction of halogen substituents in the phenolate rings of the chelators enhanced the cytotoxicity of the respective Cu(II) complexes.
TL;DR: In the absence of any additional ligands, the efficient N-arylation of nitrogen-containing heterocycles with aryl iodides catalyzed by relative low catalyst amount of Cu(OAc)2·H2O was developed.
TL;DR: 2-arylhdrazononitriles were used as key synthons for the preparation of wide variety of new, uniquely substituted heterocyclic substances and have promising antimicrobial activities against Gram negative bacteria, Gram positive bacteria and Yeast.
TL;DR: The synthesis and extensive biological study of two new tridentates ligands based on pyrazole and triazole suggest that these compounds induce DNA damage and thus exert a different mechanism of action compared to other azole derivatives.
TL;DR: A base mediated reaction of α-diazo-β-ketosulfone with nitroalkenes affords sulfonylpyrazoles as single regioisomers in excellent yield in a one-pot room temperature reaction.
TL;DR: A pyrazole-based fluorescent sensor, 5-amino-3-(5-phenyl-1H-pyrrol-2-yl)-1H pyrazoles-4-carboxamide (compound 1), was studied for fluoride anion (F−) detection in organic or water-containing solution as mentioned in this paper.
Abstract: A new pyrazole-based fluorescent sensor, 5-amino-3-(5-phenyl-1H-pyrrol-2-yl)-1H-pyrazole-4-carboxamide (compound 1), was studied for fluoride anion (F−) detection in organic or water-containing solution. This compound displayed both changes in UV–vis absorption and fluorescence emission spectra upon addition of F−. With increasing of F−, blue emission intensity increases drastically and reaches saturation with 607-fold enhancement at 424 nm. The results indicate that compound 1 has highly selectivity for fluoride detection over other anions, such as Cl−, Br−, I−, HSO4−, H2PO4− and AcO− in DMSO or aqueous DMSO solutions. 1H NMR titration and other experiments confirm that the sensing process is mainly from the deprotonation of the pyrazole–NH in compound 1.