Showing papers on "Pyrazole published in 2008"
TL;DR: The antiviral evaluation of some selected new products showed that they have promising antiviral activity against hepatitis-A virus (HAV) and herpes simplex virus type-1 (HSV-1).
195 citations
TL;DR: A series of novel 1-arylmethyl-3-aryl-1H-pyrazole-5-carbohydrazide hydrazone derivatives were synthesized and the effects of all the compounds on A549 cell growth were investigated, showing that all compounds had almost inhibitory effects on the growth of A549 cells.
191 citations
TL;DR: It was found that title compounds 4a and 4g had the same inactivation effects against TMV as the commercial product Ningnanmycin, the first report on the antiviral activity of pyrazole derivatives containing an oxime moiety.
Abstract: Target compounds 4a- n were obtained by the reaction of 1-substituted phenyl-3-methyl-5-substituted phenylthio-4-pyrazolaldoximes (3) with chloromethylated heterocyclic compounds (ClCH 2-R 3) under reflux conditions in ethanol. Subsequently, the oxidation of 4a- e with KMnO 4 in HOAc at room temperature afforded eight new compounds, 5a- h. The synthesized compounds were characterized by physical constants, and the structures of the title compounds were confirmed by IR, (1)H NMR, (13)C NMR, and elemental analysis. The bioassay revealed that the compounds possessed antiviral activities. It was found that title compounds 4a and 4g had the same inactivation effects against TMV (EC 50 = 58.7 and 65.3 microg/mL) as the commercial product Ningnanmycin (EC 50 = 52.7 microg/mL). To the best of our knowledge, this is the first report on the antiviral activity of pyrazole derivatives containing an oxime moiety.
176 citations
TL;DR: The use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and this modification is used in a straightforward synthesis of fluorination analogs of Tebufenpyrad with acaricide activity.
Abstract: The preparation of N-methylpyrazoles is usually accomplished through reaction of a suitable 1,3-diketone with methylhydrazine in ethanol as the solvent. This strategy, however, leads to the formation of regioisomeric mixtures of N-methylpyrazoles, which sometimes are difficult to separate. We have determined that the use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and we have used this modification in a straightforward synthesis of fluorinated analogs of Tebufenpyrad with acaricide activity.
174 citations
TL;DR: Seven new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones 4a-g have been synthesized by the oxidation of 2-Hydroxychalcone analogues of pyrazole 3a-G with hydrogen peroxide in KOH-MeOH by Algar Flynn Oymanda reaction.
172 citations
TL;DR: The structural differences indicate that the backbone of such dicarboxylate ligands plays an important role in governing the structures of such metal-organic coordination architectures, and the chelating bipyridyl-like ligand H leads to the formation of these coordination polymers with one-dimensional structures by occupying the coordination sites of metal ions.
Abstract: Seven new d10 metal coordination polymers with isomeric benzenedicarboxylates and 3-(2-pyridyl)pyrazole ligands, [Zn2L2(1,2-BDC)(H2O)]n (1), {[Cd2(HL)2(1,2-BDC)2]·H2O}n (2), [Cd(HL)(1,2-BDC)(H2O)]n (3), [Zn(HL)(1,3-BDC)(H2O)·3H2O]n (4), [Cd2L2(1,3-BDC)(H2O)]n (5), [Zn(HL)2(1,4-BDC)]n (6) and [Cd(HL)2(1,4-BDC)]n (7) (BDC = benzenedicarboxylate, HL = 3-(2-pyridyl)pyrazole), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses reveal that each complex takes a different one-dimensional (1D) chain structure. In 1–7, the BDCs act as bridging ligands, exhibiting rich coordination modes to link metal ions. The three BDC isomers exhibit different coordination modes: µ1-η1:η1/µ3-η2:η1, µ3-η1:η2/µ3-η2:η1, µ2-η1:η1/µ1-η1:η0 and µ1-η1:η1/µ1-η1:η0 for 1,2-BDC, µ1-η1:η1/µ1-η1:η0 and µ1-η1:η0/µ2-η2:η1 for 1,3-BDC, and µ1-η1:η0/µ1-η0:η1, µ1-η1:η0/µ1-η1:η0 and µ1-η1:η1/µ1-η1:η1 for 1,4-BDC, respectively. In these complexes, HL acts as a simple bidentate chelate ligand (in 2, 3, 4, 6 and 7), similar to 2,2′-bipyridine, or as a tridentate chelate-bridging ligand (in 1 and 5) via deprotonation of the pyrazolyl NH group and coordination of the pyrazolyl N atom to a second metal ion. The structural differences indicate that the backbone of such dicarboxylate ligands plays an important role in governing the structures of such metal–organic coordination architectures, and the chelating bipyridyl-like ligand HL leads to the formation of these coordination polymers with one-dimensional structures by occupying the coordination sites of metal ions. Moreover, the photoluminescent properties of complexes 1–7 were also studied in the solid-state at room temperature.
139 citations
TL;DR: Two series of pyrazole derivatives were synthesized by parallel solution-phase synthesis and were assayed as inhibitors of Mycobacterium tuberculosis and showed high activity against MTB.
128 citations
TL;DR: The preliminary screening for the antitumor activity of all newly synthesized compounds was carried out against Ehrlich Ascites Carcinoma tumor cells.
119 citations
TL;DR: The attachment of bromoacetyl moiety to pyrazole ring can be considered as a breakthrough in developing a new therapeutic antifungal agent related to phenylpyrazole system.
118 citations
TL;DR: The use of fluorinated alcohols such as trifluoroethanol and hexafluoroisopropanol as solvents is shown to dramatically increase the regioselectivity in the pyrazole formation from 1,3-diketone with methylhydrazine.
Abstract: In previous studies, our group has shown that the use of fluorinated alcohols such as trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation from 1,3-diketone with methylhydrazine. We have now applied this synthetic method to the preparation of new fluorinated pyrazoles, which have then been used as synthetic intermediates in the preparation of fluorinated analogs of Tebufenpyrad, a commercial acaricide. These compounds display a strong acaricidal activity that is either comparable to or better than that of the commercial compound.
117 citations
TL;DR: The bioassay results showed that title compounds possessed weak to good anti-TMV bioactivity with 4l showing significant enhancement of disease resistance in tobacco leaves with high affinity for TMV CP.
TL;DR: Molecular modeling and comparison of molecular models of 5a enantiomers with that of celecoxib model shows that 5a (enantiomer-1) and 5a-2 have more hydrogen bonding interactions in the catalytic domain of COX-2 enzyme than cele Coxib.
TL;DR: An efficient copper-catalyzed N-arylation and N-heteroarylation reactions of imidazole, pyrrole, indole, pyrazole, and perimidine with aryl or heteroaryl halides using pyridine-functionalized 1,3-diketone as ligands have been investigated as discussed by the authors.
TL;DR: Cyclic voltammetry and density functional theory calculations suggest that the lowest-energy excited state is probably best described as heavily mixed pi(L)/d(Pt)/p(Cl) --> pi*(L) (IL/MLCT/LLCT) in character.
Abstract: 1,3-Bis(1-pyrazolyl)-5-methyl-benzene, HL2, undergoes cyclometalation at the C2 position upon reaction with K2PtCl4, to generate an N∧C∧N-coordinated complex, PtL2Cl. This compound is luminescent in degassed solution at 298 K, emitting in the blue region of the spectrum on the microsecond time scale (λmax = 453 nm, τ = 4.0 μs, Φlum = 0.02, in CH2Cl2). Compared to the analogous complex Pt(dpyb)Cl that incorporates pyridyl rather than pyrazole rings {dpybH = 1,3-di(2-pyridyl)-benzene}, the excited state is displaced to higher energy by 1700 cm−1. This effect is rationalized in terms of the poorer π-acceptor nature of pyrazolyl compared to pyridyl rings, leading to destabilization of the lowest unoccupied molecular orbital, which is largely localized on the heteroaromatic rings in both cases. Cyclic voltammetry and density functional theory calculations reinforce this interpretation, and suggest that the lowest-energy excited state is probably best described as heavily mixed πL/dPt/pCl → π*L (IL/MLCT/LLCT) i...
TL;DR: In this article, the copper pyrazole complex based phosphomolybdates are self assembled at room temperature from an aqueous solution containing sodium molybdate, cupric chloride, and pyrazoles acidified with phosphoric acid.
Abstract: Five copper pyrazole complex based phosphomolybdates are self assembled at room temperature from an aqueous solution containing sodium molybdate, cupric chloride, and pyrazole acidified with phosphoric acid: one-dimensional (1D) chains in [{Cu(pz)(H2O)}{Cu(pz)3(H2O)}{Cu(pz)4}{P2Mo5O23}], 1, copper pyrazole complex intercalated two-dimensional (2D) sheets in {Cu(pz)2(H2O)4}[{Cu(pz)2(H2O)}2{Cu(pz)4}2{HP2Mo5O23}2]·6H2O, 2, hexadecameric water clusters incorporated between 1D chains in [{Cu(pz)4}3{Cu(pz)3(H2O)}2{HP2Mo5O23}2]·9H2O, 3, a water-mediated interpenetrated three-dimensional (3D) network in [{Cu(pz)4}2{H2P2Mo5O23}]·H2O, 4, and copper pyrazole complex pillared 2D phosphomolybdate sheets in [{Cu(pz)2}P2Mo2O12(H2O)2], 5. Detailed structural characterization of these solids was established by single crystal and powder X-ray diffraction techniques, FTIR, and thermal analysis. This paper proposes intuitive mechanisms to provide molecular insights into the role of in situ copper pyrazole complexes generated...
TL;DR: Using this approach, several derivatives of Bippyphos are prepared to probe the structure and activity relationships of this family of phosphine ligands and the utility of these ligands in Pd-catalyzed amination reactions and other cross-coupling reactions is demonstrated.
TL;DR: The reaction of cerium(IV) ammonium nitrate (CAN) with a range of N-(p-anisyl)azoles in acetonitrile or methanol solvents leads to N-dearylation releasing the parent NH-azole and p-benzoquinone in comparable yields.
Abstract: The reaction of cerium(IV) ammonium nitrate (CAN) with a range of N-(p-anisyl)azoles in acetonitrile or methanol solvents leads to N-dearylation releasing the parent NH-azole and p-benzoquinone in comparable yields. The scope and limitations of the reaction are explored. It was successful with 1-(p-anisyl)pyrazoles, 2-(p-anisyl)-1,2,3-triazoles, 2-(p-anisyl)-2H-tetrazoles, and 1-(p-anisyl)pentazole. The dearylation renders the p-anisyl group as a potentially useful N-protecting group in azole chemistry. The azole released in solution from 1-(p-anisyl)pentazole is unstable HN5, the long-sought parent pentazolic acid. p-Anisylpentazole samples were synthesized with combinations of one, two, and three 15N atoms at all positions of the pentazole ring. The unstable HN5/N5- produced at −40 °C did not build up in the solution but degraded to azide ion and nitrogen gas with a short lifetime. The 15N-labeling of the N3- ion obtained from all samples proved unequivocally that it came from the degradation of HN5 (ta...
TL;DR: A series of novel pyrazole oxime derivatives containing a 2-chloro-5-thiazolyl moiety were synthesized and showed low acaricidal activity against Tetranychus cinnabarinus, while some title compounds displayed fungicidal and plant growth regulatory activities.
Abstract: A series of novel pyrazole oxime derivatives containing a 2-chloro-5-thiazolyl moiety were synthesized. Their structures were confirmed by (1)H NMR, (13)C NMR, and elemental analysis. The preliminary bioassays showed that all of the title compounds had low acaricidal activity against Tetranychus cinnabarinus . However, most of them exhibited excellent insecticidal activity against Aphis medicagini at the dosage of 0.5 mg/mL, and some compounds still showed good insecticidal activity against A. medicagini even at the dosage of 0.2 mg/mL. Meanwhile, some title compounds displayed fungicidal and plant growth regulatory activities.
TL;DR: Hydrazonyl bromides 2a,b reacted with active methylene compounds to afford the corresponding 1,3,4,5-tetrasubstituted pyrazole derivatives 5-12a, b.
Abstract: Hydrazonyl bromides 2a,b reacted with active methylene compounds (dibenzoylmethane, acetylacetone, ethyl acetoacetate, phenacyl cyanide, acetoacetanilide, ethyl cyanoacetate, cyanoacetamide and malononitrile) to afford the corresponding 1,3,4,5- tetrasubstituted pyrazole derivatives 5-12a,b. Reaction of 12a,b with formamide, formic acid and triethyl orthoformate give the pyrazolo[3,4-d]pyrimidine, pyrazolo[3,4- d]pyrimidin-4(3H)one and 5-ethoxymethylene-aminopyrazole-4-carbo-nitrile derivatives 13-15a,b, respectively. Compounds 15a,b reacted with benzhydrazide and hydrazine hydrate to afford pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine and [4-iminopyrazolo- [3,4-d]pyrimidin-5-yl]amine derivatives 16a,b and 17a,b. Reactions of compounds 17a,b with triethyl orthoformate and carbon disulfide give the corresponding pyrazolo[4,3-e]- [1,2,4]triazolo[1,5-c]pyrimidine derivatives 18a,b and 19a,b, respectively.
TL;DR: In this paper, a one-pot synthesis of dihydrofuro[3′,4′:5,6]pyrido[2,3-c]pyrazole and indeno[2′,1′: 5,6]-pyride derivatives has been investigated using organocatalysts that are recyclable.
TL;DR: Replacement of the carboxylic acid group in a series of previously described methylene-linked pyrazole EP(1) receptor antagonists led to the discovery of amide, reversed amide and carbamate derivatives.
TL;DR: A few pyrazole-functionalized imidazolium salts have been prepared via the reactions of N-alkylimidazole and 3,5-bis(chloromethyl)pyrazole or 2-(1-(2-chloroethyl)-5-methyl-1H-pyrazol-3-yl)-6-(5- methyl-1-vinyl- 1H-polypyridine) pyridine as discussed by the authors.
TL;DR: This in vitro study provides insights into action of palladium and platinum complexes and demonstrates the potential use of these compounds, and in particular complex 3, in the development of new anticancer agents.
Abstract: Cisplatin (cis-diamminedichloroplatinum) was first identified for its anti-bacterial activity, and was later also shown to be an efficient anticancer agent. However, the therapeutic use of this anticancer drug is somewhat limited by its toxic side effects, which include nephrotoxicity, nausea, and vomiting. Furthermore the development of drug-resistant tumours is commonly observed following therapy with cisplatin. Hence there is a need for improved platinum derived drugs to overcome these limitations. Apoptosis contributes significantly to the cytotoxic effects of anticancer agents such as cisplatin; therefore in this study the potential anticancer properties of a series of pyrazole palladium(II) and platinum(II) complexes, [(3,5-R2pz)2PdCl2] {R = H (1), R = Me (2)} and [(3,5-R2pz)2PtCl2] {R = H (3), R = Me (4)}, were evaluated by assessment of their pro-apoptotic activity. The induction of apoptosis was measured in CHO cells by the detection of phosphatidylserine (PS) exposure using the annexin V and APOPercentage™ assays; DNA fragmentation using the Terminal deoxynucleotide transferase dUTP Nick End Labelling (TUNEL) assay; and the detection of activated caspase-3. The platinum complexes were shown to be considerably more active than the palladium complexes, with complex 3 demonstrating the highest level of cytotoxic and pro-apoptotic activity. The LD50 values for complex 3 and cisplatin were 20 and 70 μM, respectively, demonstrating that the cytotoxic activity for complex 3 was three times higher than for cisplatin. Various human cancer cell lines, including CaSki, HeLa, as well as the p53 mutant Jurkat T cell line were also shown to be susceptible to complex 3. Collectively, this in vitro study provides insights into action of palladium and platinum complexes and demonstrates the potential use of these compounds, and in particular complex 3, in the development of new anticancer agents.
TL;DR: A novel pyrazole-based class of ATP competitive B-Raf inhibitors that exhibit both excellent cellular potency and striking B- Raf selectivity is described.
TL;DR: The new 1-phenyl-5-(1 H-pyrrol-1-yl)pyrazole-3-carboxamides were compared with the reference compounds AM251 and SR144528 for cannabinoid hCB 1 and hCB 2 receptor affinity and a H-bonding interaction was proposed to account for the high affinity for receptors' inactive state and the inverse agonist activity.
Abstract: The new 1-phenyl-5-(1H-pyrrol-1-yl)pyrazole-3-carboxamides were compared with the reference compounds AM251 and SR144528 for cannabinoid hCB1 and hCB2 receptor affinity. Compounds bearing 2,4-dichlorophenyl or 2,4-difluorophenyl groups at position 1 and 2,5-dimethylpyrrole moiety at position 5 of the pyrazole nucleus were generally more selective for hCB1. On the other hand, the N-cyclohexyl group at the 3-carboxamide was the determinant for the hCB2 selectivity, in particular when a 3,4-dichlorophenyl group was also present at position 1. Compound 26 was the most selective ligand for the hCB1 receptor (Ki (CB2)/Ki (CB1) = 140.7). Derivative 30, the most potent hCB1 ligand (Ki = 5.6 nM), was equipotent to AM251 and behaved as an inverse agonist in the cAMP assay (EC50 ∼1 nM). The carbonyl oxygen of both 26 and 30 formed a H-bond with K3.28(192), while the substituents at the nitrogen fitted in a pocket formed by lipophilic residues. This H-bonding interaction was proposed to account for the high affinity ...
Patent•
06 Jun 2008TL;DR: In this paper, the substitutions of the formula (I) in which the substituents are as defined in claim 1 are suitable for use as microbiocides, in which they are defined as:
Abstract: Compounds of the formula (I), in which the substituents are as defined in claim 1 are suitable for use as microbiocides.
TL;DR: The pyrazole complexes [ReCl 2 {N 2 C(O)Ph}(Hpz)(PPh 3 ) 2 ] 2 (HpZ ǫ=pyrazole), this paper, and their precursors [ReOCl 3 (PPh3 )] 4 ] 2, are stable up to ca. 200°C.
Abstract: The pyrazole complexes [ReCl 2 {N 2 C(O)Ph}(Hpz)(PPh 3 ) 2 ] 2 (Hpz = pyrazole), [ReCl 2 {N 2 C(O)Ph}(Hpz) 2 (PPh 3 )] 3 and [ReClF{N 2 C(O)Ph}(Hpz) 2 (PPh 3 )] 4 , and their precursor [ReOCl 3 (PPh 3 ) 2 ] 1 , immobilized on 3-aminopropyl functionalized silica, catalyze the cyclohexane oxidation with dioxygen, to cyclohexanol and cyclohexanone (the main product), in the absence of solvent and additives and under relatively mild conditions. Complex 4 , whose synthesis and characterization are reported herein for the first time, provides the best activity ( ca . 16% overall conversion towards the ketone and alcohol, at the O 2 pressure of 19 atm, at 150 °C, 8 h reaction time). The reaction is further promoted by pyrazinecarboxylic acid. TGA analysis shows that the supported complexes are stable up to ca . 200 °C. The use of radical traps supports the involvement of a free-radical mechanism via carbon- and oxygen-centred radicals. The effects of various factors were studied towards the optimization of the processes. Complex 4 also catalyzes the oxidation of other cycloalkanes to the corresponding cycloalkanols and cycloalkanones.
TL;DR: In this article, a tripodal pyrazolyl ligand, 5-(bis(3,5-dimethyl- 1H -pyrazol-1-ylmethyl)amino)pentan-1ol, has been synthesized.
TL;DR: A modular approach for the regiocontrolled preparation of pyrazoles bearing substituents on all three carbon atoms is described, using a switchable metal-directing group to enable sequential direct lithiation of the 3- and 5-positions of the pyrazole ring.
Abstract: A modular approach for the regiocontrolled preparation of pyrazoles bearing substituents on all three carbon atoms is described. Central to this method is the use of a switchable metal-directing group (MDG) to enable sequential direct lithiation of the 3- and 5-positions of the pyrazole ring. Pyrazole boronic esters obtained from these lithiated intermediates can undergo efficient Suzuki cross-coupling under the developed nonaqueous conditions, which minimize undesirable protolytic deboronation. Halogenation of the 4-position provides the means for substitution at the remaining carbon atom.