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Journal articles on the topic '2-pyrazoles'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 February 2022

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1

Deacon, Glen B., Peter C. Junk, and Aron Urbatsch. "Lanthanoid and Alkaline Earth Complexes Involving New Substituted Pyrazolates." Australian Journal of Chemistry 65, no. 7 (2012): 802. http://dx.doi.org/10.1071/ch12069.

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From the pyrazoles 3,5-di-(2′-furanyl)pyrazole (fu2pzH), 3-phenyl-5-(2′-thienyl)pyrazole (PhtpzH) and 3-(2′-furanyl)-5-(2′′-naphthyl)pyrazole (funappzH), a range of alkaline earth and lanthanoid pyrazolate complexes has been prepared by redox transmetallation/protolysis reactions between free metals, Hg(C6F5)2 and the pyrazoles, by reaction of I2‐activated metals with the pyrazoles, and in one case by a similar reaction of unactivated metal, in the donor solvents tetrahydrofuran (thf) and 1,2-dimethoxyethane (dme). Thus the divalent [Ca(Phtpz)2(thf)4], [Ba(Phtpz)2(thf)4] and [Ca(funappz)2(thf)

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2

Andicsová, Anita, Angelika Lásiková, Marek Fronc, Jozef Kožíšek, and Daniel Végh. "3-(2-Heteroaryl)-pyrazolotetrazoles – a subunits for losartan-like structures." Acta Chimica Slovaca 5, no. 2 (2012): 220–24. http://dx.doi.org/10.2478/v10188-012-0033-z.

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Abstract A modification of biphenylyltetrazole moiety of Losartan (A) by 3-(2-heteroaryl)-pyrazolotetrazole (B) is described. Ketone semicarbazones react with two moles of phosphorus oxychloride-dimethylformamide with the formation of 3-substituted pyrazol-4-carbaldehydes. The transformations of 3-substituted pyrazole-4- carboxaldehydes to 3-substituted pyrazole-4-nitriles were carried out by reaction of hydroxylamine in DMFA. The prepared cyano pyrazoles were converted to tetrazoles by heating with trimethylsilylazide and dibuthyltinoxide in toluene.

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3

Gill, Agagia, Udo R. Werz, and Gerhard Maas. "N-vinylation and N-allylation of 3,5-disubstituted pyrazoles by N–H insertion of vinylcarbenoids." Zeitschrift für Naturforschung B 70, no. 10 (2015): 747–56. http://dx.doi.org/10.1515/znb-2015-0115.

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AbstractA vinylcarbenoid approach toward N-functionalization of NH-pyrazoles is presented. The rhodium(II)-catalyzed reaction of methyl styryl-diazoacetate (1) or dimethyl 2-diazoglutaconate (3) with 3,5-disubstituted pyrazoles gave products of carbenoid N–H insertion in high combined yields, although regioselectivity issues posed by the pyrazole or the vinylcarbenoid moiety as well as positional and configurational isomerism concerning the C,C double bond of the latter led to product mixtures. The ambident reactivity of the vinylcarbenoid derived from 1 could be steered by the catalyst: while

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4

Jansa, Josef, Ramona Schmidt, Ashenafi Damtew Mamuye, et al. "Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents." Beilstein Journal of Organic Chemistry 13 (May 12, 2017): 895–902. http://dx.doi.org/10.3762/bjoc.13.90.

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A synthesis of tetrasubstituted pyrazoles containing two, three or four pyridinyl substituents is described. Hence, the reaction of 1,3-dipyridinyl-1,3-propanediones with 2-hydrazinopyridine or phenylhydrazine, respectively, affords the corresponding 1,3,5-trisubstituted pyrazoles. Iodination at the 4-position of the pyrazole nucleus by treatment with I2/HIO3 gives the appropriate 4-iodopyrazoles which served as starting materials for different cross-coupling reactions. Finally, Negishi cross-coupling employing organozinc halides and Pd catalysts turned out to be the method of choice to obtain

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5

Frampton, Christopher S., Michael W. Majchrzak, and John Warkentin. "Sense of sequential 1,5-sigmatropic rearrangements of dimethyl-3,3-dialkyl-3H-pyrazole-4,5-dicarboxylates. Crystal and molecular structures of two dimethyl-4,5-dialkyl-1H-pyrazole-1,3-dicarboxylates." Canadian Journal of Chemistry 69, no. 3 (1991): 373–78. http://dx.doi.org/10.1139/v91-057.

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3,3-Dialkyl-3H-pyrazole-4,5-dicarboxylic acid dimethyl esters (4), obtained by cycloaddition of R1R2C=N+=N− (R1 = R2 = CH3; R1 = CH3, R2 = CH2CH3) to CH3O2CC≡CCO2CH3, rearrange thermally by 1,5-sigmatropic alkyl shifts to both N and C. The latter rearrangement is followed by two successive 1,5-sigmatropic shifts of a methoxycarbonyl group. Final products of the threefold rearrangement were shown to be 4,5-dialkyl-1H-pyrazole-1,3-dicarboxylic acid dimethyl esters (6), rather than the isomeric 3,4-dialkyl-1H-pyrazole-1,5-dicarboxylic acid dimethyl esters (7), by means of single crystal X-ray dif

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6

Ding, Zhengwei, Qitao Tan, Mingchun Gao, and Bin Xu. "Copper-catalyzed aerobic cascade cycloamination and acyloxylation: a direct approach to 4-acyloxy-1H-pyrazoles." Organic & Biomolecular Chemistry 13, no. 16 (2015): 4642–46. http://dx.doi.org/10.1039/c5ob00409h.

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An efficient copper-catalyzed regioselective olefinic C(sp<sup>2</sup>)–H bond cycloamination and acyloxylation was developed to give acyloxylated pyrazoles under mild conditions, which combines the formation of the pyrazole skeleton and installation of an acyloxyl group in a single step.

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7

Lévai, Albert, Artur M. S. Silva, José A. S. Cavaleiro, José Elguero, Ibon Alkorta, and József Jekő. "Synthesis of 4-Aryl-3(5)-(2-hydroxyphenyl)pyrazoles by Reaction of Isoflavones and their 4-Thio Analogues with Hydrazine Derivatives." Australian Journal of Chemistry 60, no. 12 (2007): 905. http://dx.doi.org/10.1071/ch07268.

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4-Aryl-3(5)-2-(hydroxyphenyl)pyrazoles have been prepared by the reaction of isoflavones and their 4-thio analogues with hydrazine hydrate and phenylhydrazine in hot pyridine. The reaction mechanism for the formation of these pyrazoles is discussed. All the new compounds have been fully characterized by NMR spectroscopy. In [D6]DMSO, a 1H NMR study allows observation of the presence of both pyrazole annular tautomers, due to the presence of intramolecular hydrogen bonds in each tautomer (OH···N and NH···O). Theoretical calculations have been carried out on tautomers and conformers of compounds

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8

Alsayari, Abdulrhman, Abdullatif Bin Muhsinah, Yahya I. Asiri, et al. "Arylhydrazono/Aryldiazenyl Pyrazoles: Green One-Pot Solvent-Free Synthesis and Anticancer Evaluation." Letters in Organic Chemistry 17, no. 10 (2020): 772–78. http://dx.doi.org/10.2174/1570178617666200320104923.

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The aim of this study was to synthesize and evaluate the biological activity of pyrazole derivatives, in particular, to perform a “greener” one-pot synthesis using a solvent-free method as an alternative strategy for synthesizing hydrazono/diazenyl-pyridine-pyrazole hybrid molecules with potential anticancer activity. Effective treatment for all types of cancers is still a long way in the future due to the severe adverse drug reactions and drug resistance associated with current drugs. Therefore, there is a pressing need to develop safer and more effective anticancer agents. In this context, s

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9

Bertolasi, Valerio, Paola Gilli, Valeria Ferretti, Gastone Gilli, and Cristina Fernàndez-Castaño. "Self-assembly of NH-pyrazoles via intermolecular N—H...N hydrogen bonds." Acta Crystallographica Section B Structural Science 55, no. 6 (1999): 985–93. http://dx.doi.org/10.1107/s0108768199004966.

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The crystal structures of two NH-pyrazole derivatives forming intermolecular N—H...N hydrogen bonds are reported: 5-methyl-4-(3-methylpyrazol-5-yl)pyrazol-3-ol, C8H10N4O (P1), and 3-methyl-5-dihydro-1H-naphtho[1,2-d]pyrazole hemihydrochloride, C12H12N2.-C12H13N_{2}^{+}.Cl− (P2). 26 other structures are surveyed in order to obtain a deeper insight into the ways NH-pyrazoles self-assemble by means of intermolecular N—H...N hydrogen bonds in molecular crystals. A limited number of compounds form chains or dimers via homonuclear N+—H...N positive-charge-assisted hydrogen bonds, typical of proton s

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10

Muhammad, Zeinab A., Fatimah Alshehrei, Mohie E. M. Zayed, Thoraya A. Farghaly, and Magda A. Abdallah. "Synthesis of Novel Bis-pyrazole Derivatives as Antimicrobial Agents." Mini-Reviews in Medicinal Chemistry 19, no. 15 (2019): 1276–90. http://dx.doi.org/10.2174/1389557519666190313095545.

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Background: bis-heterocycles especially those containing pyrazole moiety display much better antibacterial activity than mono heterocycles. Objective: Herein, we synthesised a series of new bis-pyrazoles and investigated their antimicrobial agents. Methods: A novel series of bis-pyrazole derivatives have been synthesized in good yield by coupling reaction of cyanoacetic acid 4-[(2-cyano-acetyl)-hydrazonomethyl]-benzylidene-hydrazide with a number of diazonium salts of aromatic amines in DMF in the presence of NaOH. Refluxing of the produced hydrazones with hydrazine-hydrate in ethanolic soluti

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11

Yahyavi, Hoda, Fatemeh Hosseinzadeh, Nastaran Karimi, et al. "Synthesis and biological evaluation of 1,3,4,5-tetrasubstituted pyrazole derivatives." Zeitschrift für Naturforschung B 71, no. 9 (2016): 973–77. http://dx.doi.org/10.1515/znb-2016-0092.

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AbstractWe report a solvent-free synthesis of novel 1,3,4,5-tetrasubstituted pyrazoles and investigate their inhibitory activity against soybean 15-lipoxygenase. It was revealed that all synthesized compounds exhibited good activity, and among them, 3-(furan-2-yl)-1,4,5-triphenyl-1H-pyrazole (5j) showed 10 times stronger inhibitory activity in comparison to the reference drug quercetin.

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12

Halcrow, M. A., H. R. Powell, and M. J. Duer. "Tautomerism in 3{5}-(dimethoxyphenyl)pyrazoles." Acta Crystallographica Section B Structural Science 52, no. 4 (1996): 746–52. http://dx.doi.org/10.1107/s0108768196005204.

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The single-crystal X-ray structures of 3{5}-(2′,5′-dimethoxyphenyl)pyrazole (HI) and the hemihydrate of 3 {5}-(3/,4′-dimethoxyphenyl)pyrazole (IV) have been determined. Compound (HI) exists purely as the 5-substituted prototropomer in the crystal; the pyrazole pyrollic N—H proton is involved in a three-way hydrogen bond, involving an intramolecular contact with a methoxy oxygen donor and an intermolecular interaction to the pyridinic N atom of a neighbouring molecule, forming discrete hydrogen-bonded dimers. There is no evidence of degenerate proton transfer within the dimeric units from CPMAS

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13

Yavari, Issa, Zohreh Taheri, Maryam Naeimabadi, Samira Bahemmat, and Mohammad Halvagar. "A Convenient Synthesis of Tetrasubstituted Pyrazoles from Nitrile Imines and 2-(Thioxothiazolidin-5-ylidene)acetates." Synlett 29, no. 07 (2018): 918–21. http://dx.doi.org/10.1055/s-0036-1591921.

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Alkyl 2-(3-alkyl-4-oxo-2-thioxothiazolidin-5-ylidene)acetates react with hydrazonoyl chlorides in the presence of triethylamine to afford tetrasubstituted pyrazole derivatives. Formally, this transformation is regarded as a 1,3-dipolar cycloaddition of the exocyclic carbon–carbon double bond of the thioxothiazolidine derivatives with nitrile imines generated in situ. This efficient method provides fast access to a range of structurally diverse pyrazoles. The structure of a typical product is confirmed by X-ray crystallography.

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14

Farag, Awatef A., Mohamed F. El Shehry, Samir Y. Abbas, et al. "Synthesis of pyrazoles containing benzofuran and trifluoromethyl moieties as possible anti-inflammatory and analgesic agents." Zeitschrift für Naturforschung B 70, no. 7 (2015): 519–26. http://dx.doi.org/10.1515/znb-2015-0009.

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AbstractSearching for new anti-inflammatory and analgesic agents, we have prepared a series of novel pyrazoles containing benzofuran and trifluoromethyl moieties. The pyrazole derivatives have been synthesized via two routes starting from 5-(3-(trifluoromethyl)phenyl azo) salicylaldehyde. The first route involved the synthesis of 2-acetylbenzofuran and then treatment with aldehydes to afford the corresponding chalcones. The cyclization of the latter chalcones with hydrazine hydrate led to the formation of new pyrazoline derivatives. The second route involved the synthesis of benzofuran-2-carbo

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15

Sevenard, D. V., O. G. Khomutov, M. I. Kodess, et al. "Novel polyfluoroalkylated pyrazoles from 2-polyfluoroacylcycloalkanones and hydrazines: syntheses and unequivocal molecular structure assignment." Canadian Journal of Chemistry 79, no. 2 (2001): 183–94. http://dx.doi.org/10.1139/v01-003.

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The reaction between 2-trifluoroacetylcycloalkanones and methylhydrazine or phenylhydrazine exclusively yields 3-CF3-pyrazoles. When the chain length of the polyfluorinated substituent in RFC(O) group increases, 5-RF-pyrazoles are isolated. The reaction of 2-trifluoroacetylcyclohexanone with 2-hydrazinopyradine gives 5-hydroxypyrazoline, an intermediate in the formation of 5-CF3-pyrazoles. The regiochemistry of the condensation is probably controlled by the nucleophilicity of the terminal nitrogen in the mono substituted hydrazines and by the steric requirements of the RF group in the 1,3-dike

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16

Albar, Hassan A. "1,3-Dipolar Cycloaddition of Four Hydrazonoyl Chlorides to β-Diketones and α,β-Unsaturated Ketones". Journal of Chemical Research 23, № 3 (1999): 182–83. http://dx.doi.org/10.1177/174751989902300306.

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The 1,3-dipolar cycloaddition of four hydrazonoyl chloride derivatives with the sodium salt of unsymmetrical β-diketones (benzoylacetone) offers a versatile method for the regioselective synthesis of 2 H-pyrazoles in a similar fashion to the cycloaddition of the nitrilimides with α,β-unsaturated ketones and esters; the structures of the prepared isomeric pyrazole and pyrazoline derivatives are established by spectroscopic and chemical methods.

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17

Zapol’skii, Viktor A., Jan C. Namyslo, Mimoza Gjikaj, and Dieter E. Kaufmann. "Chemistry of Polyhalogenated Nitrobutadienes, Part 9: Acyclic and Heterocyclic Nitroenamines and Nitroimines from 2-Nitroperchlorobuta-1,3-diene." Zeitschrift für Naturforschung B 65, no. 7 (2010): 843–60. http://dx.doi.org/10.1515/znb-2010-0710.

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Various amino, diamino, aminothio, or benzotriazolo compounds derived from the exceedingly versatile 2-nitroperchlorobutadiene (1) gave structurally interesting and physiologically promising nitro-enamines, -imines, -amidines, and hydrazines as well as ring closure reaction products, e. g. pyrimidines and pyrazoles. Most of these reactions turned out to be highly selective with good to very good yields. The structure of the pyrazole precursor (E,E)-1-(benzotriazol-1-yl)-4,4-dichloro-3- (4-ethoxyphenylamino)-1-(4-ethoxyphenylimino)-2-nitrobut-2-ene (30), due to its exceptional substitution patt

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18

Attaryan, O. S., S. S. Martirosyan, G. A. Panosyan, and S. G. Matsoyan. "Synthesis of N-(2-vinyloxyethyl)pyrazoles." Russian Journal of General Chemistry 74, no. 8 (2004): 1264–66. http://dx.doi.org/10.1007/s11176-005-0149-6.

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19

Gerster, Holger, Michael Keim, and Gerhard Maas. "Cycloaddition reactions of acetylenic iminium salts and diazoacetates leading to pyrazole iminium salts." Zeitschrift für Naturforschung B 74, no. 4 (2019): 347–55. http://dx.doi.org/10.1515/znb-2019-0001.

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AbstractAcetylenic iminium triflates with the general formula [R–C≡ C–C(Ar)=N+R2 TfO−] were found to be excellent dipolarophiles in [3+ 2] cycloaddition reactions with diazoacetates leading to (1H-pyrazol-3(5)-yl)methanaminium triflates in high yields. The terminal acetylenic iminium salt (propyne iminium salt) [HC≡C–C(Ph)=N+Me2 TfO−] reacted with an equimolar amount of methyl diazoacetate instantaneously at 20°C to form the expected pyrazole in almost quantitative yield. When a 2:1 stoichiometry was applied, subsequent Michael addition of the pyrazole at the alkyne occurred and the bis(iminiu

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20

Kumar, Ajay, Om Prakash, Mayank Kinger, and Shiv P. Singh. "Synthesis of some new 1-aryl-4-formyl-3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles using the Vilsmeier–Haack reaction — Isolation of the key intermediate 1-aryl-3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles." Canadian Journal of Chemistry 84, no. 3 (2006): 438–42. http://dx.doi.org/10.1139/v06-015.

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Arylhydrazones of dehydroacetic acid (DHA) underwent Vilsmeier–Haack reaction to generate the corresponding 1-aryl-4-formyl-3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles (1) with the pyrone moiety of the DHA remaining intact. However, when the reaction was performed using 1 equiv. of the reagent, compounds of 1-aryl-3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles (2a–2f) were obtained, which underwent smooth conversion to 1-aryl-4-formyl-3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)pyrazoles (1) on further treatment with another equivalent of the Vilsmeier–Haack reagent. This unreported

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21

Chertkova, V. V., E. I. Chernoburova, M. Kh Dzhafarov, et al. "Functionalization of NH-unsubstituted androstano[17,16-d]pyrazoles. Synthesis of 2-arylamino-2-thioxoacetylandrostano[17,16-d]pyrazoles." Russian Chemical Bulletin 65, no. 3 (2016): 819–21. http://dx.doi.org/10.1007/s11172-016-1381-4.

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22

Yang, Yiwen, Chunxiang Kuang, Hui Jin, Qing Yang, and Zhongkui Zhang. "Efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles from 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes." Beilstein Journal of Organic Chemistry 7 (December 12, 2011): 1656–62. http://dx.doi.org/10.3762/bjoc.7.195.

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An efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles was achieved. The synthesis involves the [3 + 2] dipolar cycloaddition of 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes. The process proceeds smoothly in moderate to excellent yields. 1,3-Diaryl-4-halo-1H-pyrazoles are found to be important intermediates that can easily be converted into 1,2,5-triaryl-substituted pyrazoles via Pd-catalyzed C–H bond activation.

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23

Hartwig de Oliveira, Daniela, Fernanda Severo Sabedra Sousa, Paloma Taborda Birmann, et al. "Evaluation of antioxidant activity and toxicity of sulfur- or selenium-containing 4-(arylchalcogenyl)-1H-pyrazoles." Canadian Journal of Physiology and Pharmacology 98, no. 7 (2020): 441–48. http://dx.doi.org/10.1139/cjpp-2019-0356.

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Pyrazoles represent a significant class of heterocyclic compounds that exhibit pharmacological properties. The present study aimed to investigate the antioxidant potential of pyrazol derivative compounds in brain of mice in vitro and the effect of pyrazol derivative compounds in the oxidative damage and toxicity parameters in mouse brain and plasma of mice. The compounds tested were 3,5-dimethyl-1-phenyl-4-(phenylselanyl)-1H-pyrazol (1a), 3,5-dimethyl-4-(phenylselanyl)-1H-pyrazole (2a), 4-((4-methoxyphenyl)selanyl)-3,5-dimethyl-1-phenyl-1H-pyrazole (3a), 4-((4-chlorophenyl)selanyl)-3,5-dimethy

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24

Singh, Karan, Pawan K. Sharma, S. N. Dhawan, and Shiv P. Singh. "Synthesis and Characterisation of Some Novel Indeno[1,2-c]pyrazoles." Journal of Chemical Research 2005, no. 8 (2005): 526–29. http://dx.doi.org/10.3184/030823405774663345.

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1-(Benzothiazol-2-yl)-4-phenylindeno [1,2-c]pyrazoles (1) and 1-(4-arylthiazol-2-yl)-4-phenylindeno[1,2-c]pyrazoles (2) have been synthesised by the reaction between 1-oxo-3-phenylindan-2-carboxaldehyde (4) and 2-hydrazinobenzothiazoles or 2-hydrazinothiazoles.

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25

Pejic, Marijana, Sebastian Popp, Michael Bolte, Matthias Wagner, and Hans-Wolfram Lerner. "Functionalized Pyrazoles as Agents in C–C Cross-Coupling Reactions." Zeitschrift für Naturforschung B 69, no. 1 (2014): 83–97. http://dx.doi.org/10.5560/znb.2014-3224.

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The 1-tetrahydropyranyl-(THP-)protected pyrazoles 4-R-pz(THP) (R=pinacolatoboryl=Bpin (3a(THP)), Me3Si (4a(THP)), Me3Sn (5a(THP)), and 4-R-3,5-Ph2pz (R=Bpin (3b(THP)), Me3Si (4b(THP)), Me3Sn (5b(THP)) were obtained by the following syntheses: i) In a first step, 4-X-pz (X=Br (1a), I (2a)) and 4-X-3,5-Ph2pz (X=Br (1b), I (2b)) were reacted with 3,4-dihydro-2Hpyran (DHP) to give the related THP-protected bromo- or iodopyrazole derivatives. ii) In a second step these THP derivatives were metalated by treatment with nBuLi or iPrMgCl. Subsequent reactions of the THP-protected metallopyrazoles 4-M-p

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26

Kukharev, B. F., V. K. Stankevich, N. A. Lobanova, G. R. Klimenko, and E. Kh Sadykov. "N-(2-Vinyloxyethyl)-4,5-dihydro-1H-pyrazoles." Russian Journal of Organic Chemistry 43, no. 4 (2007): 628–29. http://dx.doi.org/10.1134/s1070428007040264.

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27

Nazarinia, M., A. Sharifian, and A. Shafiee. "Syntheses of substituted 1-(2-phenethyl)pyrazoles." Journal of Heterocyclic Chemistry 32, no. 1 (1995): 223–25. http://dx.doi.org/10.1002/jhet.5570320137.

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28

El-Shehry, Mohamed F., Emad M. El-Telbani, and H. Randa Swellem. "Synthesis of polyfunctional substituted pyrazoles." Journal of Chemical Research 2009, no. 10 (2009): 625–29. http://dx.doi.org/10.3184/030823409x12523423287039.

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Synthesis of pyrazoles incorporating substituted derivatives of 2, 4-dichloroacetic acid residues is described. Reactions with different reagents afford fused and polyfunctional substituted pyrazoles.

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29

Liu, Kun, Xinye Shang, Yuyu Cheng, Xiaoyong Chang, Pengfei Li, and Wenjun Li. "Regioselective [3 + 2]-annulation of hydrazonyl chlorides with 1,3-dicarbonyl compounds for assembling of polysubstituted pyrazoles." Organic & Biomolecular Chemistry 16, no. 42 (2018): 7811–14. http://dx.doi.org/10.1039/c8ob02352b.

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The facile approach to polysubstituted pyrazoles from hydrazonyl chlorides and 1,3-dicarbonyl compounds has been developed. Hydrazonyl chlorides reacted with N-phenyl-3-oxobutanamides smoothly to afford a series of polysubstituted pyrazoles in 67–98% yields via the [3 + 2]-cycloaddition.

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30

Utecht-Jarzyńska, Greta, Karolina Nagła, Grzegorz Mlostoń, Heinz Heimgartner, Marcin Palusiak, and Marcin Jasiński. "A straightforward conversion of 1,4-quinones into polycyclic pyrazoles via [3 + 2]-cycloaddition with fluorinated nitrile imines." Beilstein Journal of Organic Chemistry 17 (June 28, 2021): 1509–17. http://dx.doi.org/10.3762/bjoc.17.108.

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In-situ-generated N-aryl nitrile imines derived from trifluoroacetonitrile efficiently react with polycyclic 1,4-quinones, yielding fused pyrazole derivatives as the exclusive products. The reactions proceed via the initially formed [3 + 2]-cycloadducts, which undergo spontaneous aerial oxidation to give aromatized heterocyclic products. Only for 2,3,5,6-tetramethyl-1,4-benzoquinone, the expected [3 + 2]-cycloadduct exhibited fair stability and could be isolated in moderate yield (53%). The presented method offers a straightforward access to hitherto little known trifluoromethylated polycyclic

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31

Zhersh, Sergey, Oleksandr Karpenko, Vasyl Ripenko, Andrey Tolmachev, and Oleksandr Grygorenko. "Synthesis of 1-(pyrrolidin-2-ylmethyl)-1H-azoles and their piperidine-derived homologues." Open Chemistry 12, no. 1 (2014): 67–73. http://dx.doi.org/10.2478/s11532-013-0344-y.

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AbstractA convenient preparation of 1-(pyrrolidin-2-yl)-1H-pyrazoles, -imidazoles, and -1H-1,2,4-triazoles, 1-(piperidin-2-yl)-1H-pyrazoles and -1H-1,2,4-triazoles, and 1-(piperidin-3-yl)-1H-1,2,4-triazoles by alkylation of azoles (viz. pyrazoles, imidazoles, and triazoles) with N-Cbz-prolinol mesylate or its analogues and subsequent deprotection is reported. The two-step method allows for synthesis of the title compounds in 16–65% yields. The utility of the procedure has been demonstrated by multigram preparation of a 15-member building block mini-library for the lead-oriented synthesis of co

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32

Schowtka, Björn, Christoph Müller, Helmar Görls, and Matthias Westerhausen. "Synthesis, Structures, and Spectroscopic Properties of 3-Aryl-5-(2-pyridyl)pyrazoles and Related Pyrazoles." Zeitschrift für anorganische und allgemeine Chemie 640, no. 5 (2014): 916–25. http://dx.doi.org/10.1002/zaac.201300637.

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33

Mansha, Muhammad, Nisar Ullah, and Khalid Alhooshani. "Synthesis of structural analogues of GGT1-DU40, a potent GGTase-1 inhibitor." Zeitschrift für Naturforschung B 71, no. 4 (2016): 333–44. http://dx.doi.org/10.1515/znb-2016-0019.

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AbstractA series of new substituted pyrazoles 2–12 have been synthesized. The synthesized compounds are structural analogues of GGT1-DU40 1, a highly potent and selective inhibitor of protein geranylgeranyltransferase I (GGTase-I) both in vitro and in vivo. The implications of GGTase-I in oncogenesis have highlighted its potential as a cancer therapeutic target. Accordingly, the development of GGTase-I inhibitors has been a subject of much interest. The synthesis of 2–12 stemmed from the acetylation or acylation of N-function of amino acids to produce suitably modified amino acids. Meanwhile,

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34

Sheludyakov, V. D., N. E. Kuz’mina, A. M. Abramkin, et al. "Synthesis and structure of N-(2-silatranylethyl)pyrazoles." Russian Journal of General Chemistry 81, no. 12 (2011): 2478–86. http://dx.doi.org/10.1134/s1070363211120097.

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35

Hayotsyan, S. S., H. N. Khachatryan, H. S. Attaryan, and G. V. Hasratyan. "Thermal addition of pyrazoles to but-2-enal." Russian Journal of General Chemistry 86, no. 2 (2016): 412–13. http://dx.doi.org/10.1134/s1070363216020365.

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36

Driowya, Mohsine, Hassan Allouchi, José Manuel Gally, Pascal Bonnet, and Gérald Guillaumet. "Synthesis of novel series of 7,7′-(substituted methylene)bis-imidazo[1,2-b]pyrazoles via an acid catalyzed one-pot three-component reaction." New Journal of Chemistry 42, no. 8 (2018): 5728–41. http://dx.doi.org/10.1039/c7nj05088g.

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An efficient and rapid synthesis of new series of N-alkyl-2-aryl-5H-imidazo[1,2-b]pyrazoles has been achieved in high yields through a three-component reaction of 3-amino-4-substituted pyrazoles, aromatic aldehydes and isocyanides mediated by acid catalysts.

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37

Shi, Tao, Zhaoxiao Wu, Tingting Jia, et al. "Sequential [3+2] annulation reaction of prop-2-ynylsulfonium salts and hydrazonyl chlorides: synthesis of pyrazoles containing functional motifs." Chemical Communications 57, no. 68 (2021): 8460–63. http://dx.doi.org/10.1039/d1cc02735b.

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38

Katla, Ramesh, Rakhi Chowrasia, Padma S. Manjari, Caren D. G. da Silva, Beatriz F. dos Santos, and Nelson L. C. Domingues. "[Ce(l-Pro)2]2 (Oxa) as a heterogeneous recyclable catalyst: synthesis of pyrazoles under mild reaction conditions." New Journal of Chemistry 40, no. 11 (2016): 9471–76. http://dx.doi.org/10.1039/c6nj01723a.

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39

Signorello, Maria Grazia, Federica Rapetti, Elda Meta, Adama Sidibè, Olga Bruno, and Chiara Brullo. "New Series of Pyrazoles and Imidazo-Pyrazoles Targeting Different Cancer and Inflammation Pathways." Molecules 26, no. 19 (2021): 5735. http://dx.doi.org/10.3390/molecules26195735.

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(1) Background: different previously synthesized pyrazoles and imidazo-pyrazoles showed interesting anti-angiogenic action, being able to interfere with ERK1/2, AKT and p38MAPK phosphorylation in different manners and with different potency; (2) Methods: here, a new small compound library, endowed with the same differently decorated chemical scaffolds, has been synthetized to obtain new agents able to inhibit different pathways involved in inflammation, cancer and human platelet aggregation. (3) Results: most of the new synthesized derivatives resulted able to block ROS production, platelet ag

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40

Schmidt, Andreas, and Andrij Dreger. "Recent Advances in the Chemistry of Pyrazoles. Part 2. Reactions and N-Heterocyclic Carbenes of Pyrazole." Current Organic Chemistry 15, no. 16 (2011): 2897–970. http://dx.doi.org/10.2174/138527211796378497.

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Bharathi, R. "In vitro and molecular docking studies of an antiinflammatory scaffold with human peroxiredoxin 5 and tyrosine kinase receptor." Bioinformation 16, no. 11 (2020): 929–36. http://dx.doi.org/10.6026/97320630016929.

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A new series of 4-(3-(2-amino-3,5-dibromophenyl)-1-(4-substitutedbenzoyl)-4,5-dihydro-1H-pyrazol-5-yl)benzonitrile (4a-h) compounds were synthesized and evaluated for in-vitro anti-inflammatory activities. The spectral (IR, NMR) and elemental analyses data of the product indicated the formation of new pyrazoles 4a-h. Compound 4e exhibited potent anti-inflammatory property with 85.45 % inhibitions. This value was compared with standard diclofenac sodium. This data is explained using molecular docking analysis of receptor-ligand binding. These results demonstrated that pyrazole derivatives are p

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42

Gaddam, Ganga Reddy, Pramod Kumar Dubey, and Venkata Ramana Reddy Chittireddy. "Synthesis of Indolyl Pyrazole Scaffolds as Potential Anti-cancer Agents and their Molecular Modelling Studies." Letters in Drug Design & Discovery 17, no. 7 (2020): 828–39. http://dx.doi.org/10.2174/1570180816666191024103534.

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Background:: Indole and pyrazoles are one of the prime structural units in the field of medicinal chemistry and have been reported to exhibit a variety of biological activities specifically anti-cancer. In view of their medicinal significance, we synthesized a conjugate of the two moieties to get access to newer and potential anti-cancer agents. Methods: Indolyl pyrazoles [3-(1,3-diphenyl-1H-pyrazol-4-yl)-2-(1-methyl-1H-indole-3-carbon yl)acrylonitriles] (4a-l) were synthesized by adopting simple and greener protocol and all the synthesized derivatives were docked against Bcl-2 protein and the

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Li, Yao, Deng Hong, Ping Lu, and Yanguang Wang. "Synthesis of pyrazoles from 2-azidoacrylates and hydrazonyl chlorides." Tetrahedron Letters 52, no. 32 (2011): 4161–63. http://dx.doi.org/10.1016/j.tetlet.2011.05.147.

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44

Catalan, Javier, Fernando Fabero, Rosa M. Claramunt, et al. "New ultraviolet stabilizers: 3- and 5-(2'-hydroxyphenyl)pyrazoles." Journal of the American Chemical Society 114, no. 13 (1992): 5039–48. http://dx.doi.org/10.1021/ja00039a014.

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Janjić, Monika, Rok Prebil, Uroš Grošelj, et al. "A Simple Synthesis of 5-(2-Aminophenyl)-1H-pyrazoles." Helvetica Chimica Acta 94, no. 9 (2011): 1703–17. http://dx.doi.org/10.1002/hlca.201100055.

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NAZARINIA, M., A. SHARIFIAN, and A. SHAFIEE. "ChemInform Abstract: Syntheses of Substituted 1-(2-Phenethyl)pyrazoles." ChemInform 26, no. 30 (2010): no. http://dx.doi.org/10.1002/chin.199530138.

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Fahim, Asmaa Mahmoud, Ahmad Mahmoud Farag, Mohamed Rabie Shaaban, and Eman Ali Ragab. "Synthesis and DFT study of novel pyrazole, thiophene, 1,3-thiazole and 1,3,4-thiadiazole derivatives." European Journal of Chemistry 9, no. 1 (2018): 30–38. http://dx.doi.org/10.5155/eurjchem.9.1.30-38.1675.

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Regioselective facile synthesis of innovative heterocycles from the reaction of 2-cyano-N-cyclohexylacetamide (3) with hydrazonoyl chloride (4) in basic condition afforded amino pyrazole derivative 6. The behavior of acetamide 3 with phenylisothiocyanate in DMF/KOH surveyed by addition of the α-halo ketones to yeild the corresponding thiophene derivative 13a, 13b, 16, 18 and 1,3-thiazoles 21. Reaction of intermediate potassium salt 9 with hydrazonoyl chloride 22a-e furnished the corresponding 1,2,4-thiadiazoles 24a-e. Density functional theory (DFT) calculations at the B3LYP and HF techniques

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48

Ponnala, Shashikanth, and Devi Prasad Sahu. "Iodine‐Mediated Synthesis of 2‐Arylbenzoxazoles, 2‐Arylbenzimidazoles, and 1,3,5‐Trisubstituted Pyrazoles." Synthetic Communications 36, no. 15 (2006): 2189–94. http://dx.doi.org/10.1080/00397910600638879.

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Chirkova, Zhanna V., Sergey I. Filimonov, and Igor G. Abramov. "SYNTHESIS OF BENZOFURAN-5,6-DICARBONITRILES ANNELATED WITH PYRAZOLE CYCLE." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 6 (2017): 45. http://dx.doi.org/10.6060/tcct.2017606.5576.

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The principal method for the preparation of substituted 4-formyl-1H-pyrazoles was the treatment of hydrazones of different structure with Vilsmeier-Haack reagent. However, for the heterocyclic benzofuran system this reaction is rarely used. Synthetic methods for preparation of novel substituted 3-(4-fomyl-1H-pyrazole-3-yl)-2-methylbenzofuran-5,6-dicarbonitriles and 2-(1H-pyrazole-4-yl)-benzofuran-5,6-dicarbonitriles were developed by modification of 2,3-disubstituted benzofuran-5,6-dicarbonitriles via Vilsmeier-Haack reaction. New substituted 3-(4-fomyl-1H-pyrazole-3-yl)-2-methylbenzofuran-5,6

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50

Noshiranzadeh, Nader, Ali Ramazani, Amir Tofangchi Mahyaria, Katarzyna Ślepokurab, and Tadeusz Lisb. "Stereoselective Synthesis and Single Crystal X-Ray Structures of Some Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives." Zeitschrift für Naturforschung B 63, no. 1 (2008): 65–70. http://dx.doi.org/10.1515/znb-2008-0109.

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A one-pot synthesis of sterically congested electron-poor N-vinyl pyrazoles in fairly good yields by the reaction of ethyl 3-phenyl-2-propynoate, pyrazoles and triphenylphosphine is reported. The structures of these compounds were confirmed by IR, 1H, and 13C NMR spectroscopy, and single crystal X-ray structure determination. The structural analysis of the products indicated that the reaction is completely regio- and stereoselective.

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