- REACTIONS OF SODIUM SALTS OF TOSYLHYDRAZONE COMPOUNDS WITH SILVER CHROMATE. FORMATION OF INDAZOLE, PYRAZOLE, AND BENZONITRILE DERIVATIVES.
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Tropone tosylhydrazone sodium salt was allowed to react with silver chromate to give 2-tosyl-2H-indazole. The reaction is thought to proceed through the cyclization of the hydrazyl radical intermediate. Under the same conditions, sodium salts of m-nitrobenzaldehyde tosylhydrazone (5), benzylideneacetone tosylhydrazone derivatives (7a and 7b), and beta -ionone tosylhydrazone (9) reacted to yield m-nitrobenzonitrile from 5 and pyrazole derivatives from 7a, b, and 9, respectively. m-Nitrobenzonitrile is formed by homolytic fission of nitrogen-nitrogen bond of 5. Formation of the pyrazole derivatives can be explained by intramolecular 1,3-dipolar additions of the corresponding diazo intermediates.
- Saito,Toda,Mukai
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- Discovery of pyrazole N-aryl sulfonate: A novel and highly potent cyclooxygenase-2 (COX-2) selective inhibitors
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Based on a new pyrazole sulfonate synthetic method, a novel class of molecules with a basic structure of pyrazole N-aryl sulfonate have been designed and synthesized. The interest in conducting intensive research stems from quite evident anti-inflammatory effects exhibited by the compounds in preliminary animal experiments. A series of compounds were synthesized by different substitutions of the R1, R2, and R3 groups. Within the series, 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and phenyl 5-methyl-3-(4-(trifluoromethyl) phenyl)-1H-pyrazole-1-sulfonate exhibited excellent anti-inflammatory activity (% inhibition of auricular edemas = 27.0 and 35.9, respectively); the in vivo analgesic activity of phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate was confirmed to be effective (inhibition ratio of writhing = 50.7% and 48.5% separately), and compounds phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate, 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate were identified as selective COX-2 inhibitors (SI = 455, 10,497 and >189 severally). In Acute Oral Toxicity assays conducted in vivo, the lethal dose 50 (LD50) of 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate to mice was >2000 mg/kg BW.
- Guo, Quanping,Wang, Mengran,Wang, Rui,Xu, Zhaoqing,Yao, Haiyan
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- Predicting the catalytic activity of azolium-based halogen bond donors: an experimentally-verified theoretical study
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This report demonstrates the successful application of electrostatic surface potential distribution analysis for evaluating the relative catalytic activity of a series of azolium-based halogen bond donors. A strong correlation (R2> 0.97) was observed between the positive electrostatic potential of the σ-hole on the halogen atom and the Gibbs free energy of activation of the model reactions (i.e., halogen abstraction and carbonyl activation). The predictive ability of the applied approach was confirmed experimentally. It was also determined that the catalytic activity of azolium-based halogen bond donors was generally governed by the structure of the azolium cycle, whereas the substituents on the heterocycle had a limited impact on the activity. Ultimately, this study highlighted four of the most promising azolium halogen bond donors, which are expected to exhibit high catalytic activity.
- Bolotin, Dmitrii S.,Il'in, Mikhail V.,Novikov, Alexander S.,Suslonov, Vitalii V.,Sysoeva, Alexandra A.
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p. 7611 - 7620
(2021/09/22)
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- Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3-Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
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3-(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium Ptb ligand under Jeffery's and Fu's conditions. The formation of these three-carbon building blocks is embedded into consecutive three- and pseudo-four-component syntheses of 3-(hetero)aryl and 3,5-diarylpyrazoles with a broad substitution pattern in moderate to excellent yield.
- Stephan, Marvin,Panther, Jesco,Wilbert, Fabio,Ozog, Pauline,Müller, Thomas J. J.
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p. 2086 - 2092
(2020/03/23)
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- Monohydrochloride Assisted Synthesis of Functionalized Isoxazoles and Pyrazoles from Allenic Ketones: First Synthesis of (Z)-2-Methyl-7H-benzo[b]pyrazolo[5,1-d][1,5]oxazocines
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A facile hydrochloride promoted regioselective synthesis of isoxazoles and pyrazoles from 1,2-allenic ketones is reported. The reaction has been scaled up to gram scale. A direct 8-endo dig ring annulations towards the first synthesis of (Z)-2-methyl-7H-b
- Sarkar, Debayan,Sahoo, Sushree Ranjan
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p. 2035 - 2049
(2019/03/07)
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- Pyrazole compound containing N-aryl sulfonate and synthesis and application thereof
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The invention discloses a pyrazole compound containing N-aryl sulfonate. A structural formula of the pyrazole compound is shown in the description. Proofed by pharmacological study, the pyrazole compound has the advantages that the activity of cyclooxygenase 2 is inhibited; the high-efficiency inhibition function on the generation of cyclooxygenase 2 due to inflammation mediums is realized, so that the pyrazole compound can be used as an active matter, and the prepared anti-inflammation medicine can be used for treating the inflammations, such as rheumatic arthritis and rheumatalgia, and the diseases and symptoms, such as fevers.
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- Iron(III) phthalocyanine chloride-catalyzed oxidation-aromatization of α,β-unsaturated ketones with hydrazine hydrate: Synthesis of 3,5-disubstituted 1H-pyrazoles
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We have developed an iron(III) phthalocyanine chloride-catalyzed oxidation-aromatization of α,β-unsaturated ketones with hydrazine hydrate. Various 3,5-disubstituted 1H-pyrazoles were obtained in good to excellent yields. This method offers several advantages, including room-temperature conditions, short reaction time, high yields, simple work-up procedure, and use of air as an oxidant. The catalyst can be recovered and reused five times without loss of activity.
- Zhao, Junlong,Qiu, Jun,Gou, Xiaofeng,Hua, Chengwen,Chen, Bang
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p. 571 - 578
(2016/04/20)
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- An efficient synthesis of isoxazoles and pyrazoles under ultrasound irradiation
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A series of 5-arylisoxazole and 5-aryl-1H-pyrazole derivatives was synthesized by the reaction of 3-(dimethylamino)-1-arylprop-2-en-1-one with hydroxylamine hydrochloride or hydrazine hydrate under ultrasound irradiation without using any catalyst. This m
- Huang, Zhi-Bin,Li, Li-Li,Zhao, Yan-Wei,Wang, Hui-Yuan,Shi, Da-Qing
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p. E309-E313
(2014/11/07)
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- Synthesis of aryl-substituted or aryl-fused N-hydroxyethyl and N-hydroxymethypyrazole derivatives as potential ligands for the estrogen receptor
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A new series of N-hydroxyethylpyrazole (12a-f) and N-hydroxymethylpyrazole derivatives (15a-f) were designed for their estrogenic activities, having a 11.0 ± 0.5 A distance between their two hydroxyl groups, aliphatic-OH and phenolic-OH similar to 17β-estradiol (E2) as an endogenous hormone. To synthesize the title compounds, the key intermediate 1,3-dicarbonyl derivatives (2 and 8), were treated with hydrazine hydrate to produce the pyrazole ring 5 and 9. Further hydroxyalkylation of the latter produced the title pyrazoles. The position of hydroxyethyl or hydroxymethyl substituents in the products was determined through 2D NOE NMR spectroscopy.
- Allahyari-Devin, Maryam,Abedi, Behnam,Navidpour, Latifeh,Shafiee, Abbas
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- A regioselective synthesis of some new pyrazol-1′-ylpyrazolo[1,5-a] pyrimidines in aqueous medium and their evaluation as antimicrobial agents
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An efficient and environmental benign regioselective synthesis of some new pyrazol-1′-ylpyrazolo[1,5-a]pyrimidines (7b-h) has been accomplished via treatment of 3(5)-amino-5(3)-hydrazinopyrazole dihydrochloride (5) with several unsymmetrical 1,3-diketones (6b-h) using water as a solvent without any catalysts or additives. The structure of 7b-h was established on the basis of rigorous analysis of 1H, 13C NMR, IR spectral data and MS. Eight compounds (7a-h) were screened for their antibacterial activity against two gram-positive and two gram-negative bacteria and compounds (7a, b, d and e) for antifungal activity against four phytopathogenic fungi. Compounds 7c and 7e manifest rather broad antibacterial activity than standard antibiotics. One lead compound, 7a (10 mg/ml and 200 mg/ml) exhibited equipotent or more potent antifungal activity against all tested microorganisms than standard drug.
- Aggarwal, Ranjana,Sumran, Garima,Garg, Neelam,Aggarwal, Ashok
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experimental part
p. 3038 - 3046
(2011/07/08)
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- A simple and efficient synthesis of pyrazoles in water
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A simple, highly efficient, and environmentally friendly method for the synthesis of substituted 1H-pyrazoles by one-pot condensation reaction of α,β-unsaturated carbonyl compounds with tosyl hydrazide in water was developed. The reaction system exhibited tolerance with various functional groups, Aromatic moiety with both electron-rich and electron-deficient substituents could give desired products in good to excellent yields.
- Wen, Jun,Fu, Yun,Zhang, Ruo-Yi,Zhang, Ji,Chen, Shan-Yong,Yu, Xiao-Qi
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supporting information; experimental part
p. 9618 - 9621
(2011/12/14)
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- β-Acetyl-β-nitrostyrenes: Structure and use for synthesis of heteryl-containing structures
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1H, IR, and electronic absorption spectroscopy and X-ray diffraction analysis were used to establish that 1-acetyl-1-nitro-2-phenyl-and 2-(p-methoxyphenyl)ethenes have Z configuration, and their 2-(p-N, Ndimethylaminophenyl)-substituted analog exists in chloroform-d 3 as a mixture of Z and E isomers. The reactions of gem-acetylnitroethenes with N-methylpyrrole were shown to involve alkylation at the C2-reaction center of the heterocycle. The reactions of these nitroalkenes with hydrazine form pyrazoles and azines, with acetylhydrazine, the corresponding hydrazones (via transalkenylation), and with sodium azide, acetylsubstituted 1,2,3-triazoles.
- Aboskalova,Smirnova,Kataeva,Baichurin,Fel'gendler,Berkova,Berestovitskaya
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experimental part
p. 1711 - 1718
(2009/02/06)
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- 5-Hydroxy-2-pyrazolines and some of their 1-substituted analogs
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The use of 1,3-dicarbonyl compounds containing strong electron-withdrawing substituents (perfluoroalkyl, 4-nitrophenyl) at one of the carbonyl groups in reaction with hydrazine or its monosubstituted derivatives (4-nitro- and 2,4-dinitrophenylhydrazines) leads to the formation of stable intermediates for the synthesis of pyrazoles (5-hydroxy-2-pyrazolines) or their linear tautomers (hydrazones).
- Zelenin,Tugusheva,Yakimovich,Alekseev,Zerova
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p. 668 - 676
(2007/10/03)
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- Copper(II/I) complexes of a bulky tris(pyrazolylmethyl)amine ligand
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The ligand tris[3-(4-methoxyphenyl)-5-methylpyrazol-1-ylmethyl]amine (L), the copper(II) complexes [CuLCL2] 1, [CuLCL][SbF6] 2 and [CuL(H2O)][SbF6]2 3, and the copper(I) complex [CuL][CF3SO3] 4 have been prepared. Complexes 1-3 are reduced by [BPh4]- ion in a range of solvents to afford [CuL]+ ion. The [CuL]+ ion does not react with dioxygen nor carbon monoxide but does reat with chloride ion. Physicochemical and cyclic voltammetry data are reported for 1/4, along with crystal structure analyses of 1-3 and [CuL][CuCl2]. There are some notable differences between the structures and properties of these copper complexes and those reported for analogues with pyridyl- or imidazolyl amine ligands.
- Chen, Zhixuan (Jack),Karasek, Natasha,Craig, Donald C.,Colbran, Stephen B.
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p. 3445 - 3452
(2007/10/03)
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- Reactivity of p-Phenyl Substituted β-Enamino Compounds using K-10/ultrasound. I. Synthesis of Pyrazoles and Pyrazolinones
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The reactivity of the β-enamino ketones, 3-amino-l-(p-phenyl-substituted)-2-buten-l-ones la-d and β-enamino esters. Ethyl-3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d were evaluated by systematic studies of the reactions with hydrazine and methylhydrazine by reactions with solid support K-10/ultrasound and homogeneous media (reflux in ethanol or dichloromethane) yielding pyrazole rings 2a-d, Af-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization showed dependence of the reaction conditions employed as well as the substituent in the aromatic ring.
- Valduga, Claudete J.,Braibante, Hugo S.,Braibante, Mara E.F.
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p. 189 - 192
(2007/10/03)
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- Reactivity of p-phenyl substituted β-enamino compounds using K- 10/ultrasound. I. Synthesis of pyrazoles and pyrazolinones
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The reactivity of the β-enamino ketones, 3-amino-1-(p-phenyl- substituted)-2-buten-1-ones 1a-d and β-enamino esters, ethyl 3-amino-3-(p- phenyl-substituted)-2-propenoates 5a-d was systematically studied when allowed to react with hydrazine and methylhydrazine under solid support K- 10/ultrasound conditions and in homogeneous media (reflux in ethanol or dichloromethane). The products were pyrazoles 2a-d, N-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization reactions showed dependence upon the reaction conditions employed as well as upon the substituent in the aromatic ring.
- Valduga,Braibante,Braibante
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p. 1453 - 1457
(2007/10/03)
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- Synthesis of Pyrazole, 1,2,4,5-Tetrazine, and 1,2,4-Triazole Derivatives from Thiocarbonohydrazides and β-Dicarbonyl Compounds
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Reactions of acetylacetone, α-methylacetylacetone, and benzoyl- and 4-methoxybenzoylacetone with thiocarbonohydrazide yield corresponding pyrazoles with no substituent at N1.Reactions of 1-substituted thiocarbonohydrazides with acetylacetone, as well as of trifluoromethyl-substituted β-diketones and aroylacetones containing acceptor substituents with unsubstituted thiocarbonohydrazide, result in formation of corresponding 1-(N-aminothiocarbamoyl)-5-hydroxy-Δ5-pyrazolines which in some cases are converted into respective 1-(N-aminothiocarbamoyl)pyrazoles and further into 1-unsubstituted pyrazoles.Reaction of thiocarbonohydrazide with aroylacetaldehyde leads to 1,2,4,5-tetrazine-3-thiones.The product of reactions of 1,1,4-trimethylthiocarbonohydrazide with acetylacetone is a 1,2,4-triazole derivative.
- Alekseev, V. V.,Zelenin, K. N.,Yakimovich, S. I.
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p. 868 - 873
(2007/10/03)
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- 5-Hydroxy-4,5-Dihydropyrazoles
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The use of β-diketones with strong electron-withdrawing substituents in reaction with hydrazine and its monosubstituted derivatives leads to the stable intermediates of pyrazole synthesis - 5-hydroxy-4,5-dihydropyrazoles or their open chain isomers.
- Zelenin, Kirill N.,Alekseyev, Valery V.,Tygysheva, Alja R.,Yakimovitch, Stanislav I.
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p. 11251 - 11256
(2007/10/02)
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- THERMAL HETEROCYCLIZATION OF METHYL ARYL KETAZINES. REACTIONS OF THE TAUTOMERIC ENEHYDRAZINE FORM
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Over the temperature range 220-280 deg C the thermal reactions of methyl aryl ketazines (Ar=C6H5-, 4-CH3C6H4-, 4-CH3OC6H4-, and α-naphthyl-) proceed with their cyclization to give pyrazoline and benzodiazepine derivatives.With an increase in temperature to 320-350 deg C the subsequent transformations of these compounds lead to the formation of substituted pyrazoles, 1-methyl-1,2-diarylcyclopropanes isomeric olefins, low-molecular-weight aromatic hydrocarbons, and isoquinolines.
- Shurukhin, Yu. V.,Klyuev, N. A.,Grandberg, I. I.
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p. 723 - 732
(2007/10/02)
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- INVESTIGATION OF THE MECHANISMS OF FORMATION OF HETEROCYCLES BY NMR SPECTROSCOPY. III. THE EFFECT OF ELECTRONIC FACTORS ON THE KINETICS OF THE DEHYDRATION OF DIHYDROXYPYRAZOLIDINES AND HYDROXYPYRAZOLINES- THE INTERMEDIATES IN THE REACTION OF HYDRAZINE WITH 1,3-DIKETONES
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The rate constants for the dehydration of the dihydroxypyrazolidine and hydroxypyrazoline intermediates in the reaction of hydrazine with substituted benzoylacetones p-XC6H4COCH2COCH3 (X= CH3O, CH3, H, Cl, NO2) in methanol were determined by NMR spectroscopy using the stopped-flow technique.Increase in the electronegativity of the substituent leads, on the one hand, to an increase in the contribution from the reaction path involving the formation of the tautomeric pyrazoles with the participation of 3-methyl-5-(p-XC6H4)-5-hydroxypyrazoline and, on the other hand, to an increase in the rate of its conversion into the corresponding pyrazole.Analysis of the relationships between the dehydration rates and the Hammett ? constants confirms a reaction mechanism with the participation of the cyclic dihydroxypyrazolidine intermediate.
- Selivanov, S. I.,Golodova, K. G.,Abbasov, Ya. A.,Ershov, B. A.
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p. 1361 - 1364
(2007/10/02)
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