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Journal articles on the topic 'Pyrazolic acid'

Author: Grafiati

Published: 4 June 2021

Last updated: 16 February 2022

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1

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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2

Sophy, Mohamed Ahmed Elian, and Mohamed Ahmed Mahmoud Abdel Reheim. "Synthesis of Some New 1, 3, 4-Oxadiazole, Pyrazole, and Pyrimidine Bearing Thienopyrazole Moieties." Current Organic Synthesis 17, no. 8 (2020): 661–70. http://dx.doi.org/10.2174/1570179417999200730215318.

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Aim and Objective: According to the literature survey, pyrazole is a unique template that is associated with several biological activities. This article highlighted the research work of many researchers reported in the literature for synthesis and different pharmacological activities of the pyrazole nucleus. In the present work, pyrazol- 3-one 1 was reacted with cyanoacetic acid hydrazide and elemental sulfur to afford the corresponding thieno[3,2-c]pyrazol-6-carbohydrazide 3 derivatives. The latter compound reacted with some electrophilic reagents such as DMF-DMA, triethylorthoformate, arylid

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3

Perepelytsya, O. O., I. M. Yaremiy, K. P. Kupchanko, N. V. Panasenko, M. K. Bratenko, and M. V. Vovk. "Synthesis and hypoglycemic activity of derivatives of 4-((1,3-thiazolydine-5-yliden)methy)pyrazole-3-carbonic acid and its esters." Chernivtsi University Scientific Herald. Chemistry, no. 819 (2019): 37–44. http://dx.doi.org/10.31861/chem-2019-819-06.

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An effective preparative method of synthesis of a series of new (pyrazole-4-il)methylenethiazolidine structures has been elaborated. The structures are functionalized in the 3rd position by the carboxylate or carboxyle group and in the 3rd and 5th positions of the thiazolidine cycle – by the oxo-, thio- or iminogroups. The method involves condensation of 4-formylpyrazole-3-carbonic acids and their ethyl esters with a series of the substituted thiazolidines: 1,3-thiazolidine-2,4-dione, 4-thioxo-1,3-thiazolidine-2-one, 2-thioxo-1,3-thiazolidine-4-one and 2-imino-1,3-thiazolidine-4-one. A group o

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4

Deeb, Ali, Medhat El-Mobayed, Abdel Naby Essawy, Adel Abd El-Hamid, and Atef Mohamid Abd El-Hamid. "Heterocyclic synthesis from 3-amino-4-cyanopyrazole." Collection of Czechoslovak Chemical Communications 55, no. 3 (1990): 728–33. http://dx.doi.org/10.1135/cccc19900728.

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3-Amino-4-cyanopyrazole I reacts with hydroxylamine and with hydrazine to yield 1H,6H-3-aminopyrazolo[3,4-c]pyrazole (III and IV). Diazotized IV couples with 2-naphthol to give the arylazo derivative VI which cyclizes to 9H-naphthol[2,1-e]pyrazolo[3',4':3,4]pyrazolo[5,1-c]-[1,2,4]triazine VII by means of acetic acid. The pyrazol-5-ylthiourea obtained from I and phenyl isothiocyanate undergoes base-catalyzed cyclization to give pyrazolo[3,4-d]pyrimidinethione derivative IX. Compound I reacts with cyclohexane in the presence of zinc chloride to give the tetrahydropyrazolo[3,4-b]quinoline derivat

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5

Mantzanidou, Martha, Eleni Pontiki, and Dimitra Hadjipavlou-Litina. "Pyrazoles and Pyrazolines as Anti-Inflammatory Agents." Molecules 26, no. 11 (2021): 3439. http://dx.doi.org/10.3390/molecules26113439.

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The five-membered heterocyclic group of pyrazoles/pyrazolines plays important role in drug discovery. Pyrazoles and pyrazolines present a wide range of biological activities. The synthesis of the pyrazolines and pyrazole derivatives was accomplished via the condensation of the appropriate substituted aldehydes and acetophenones, suitable chalcones and hydrazine hydrate in absolute ethanol in the presence of drops of glacial acetic acid. The compounds are obtained in good yields 68–99% and their structure was confirmed using IR, 1H-NMR, 13C-NMR and elemental analysis. The novel derivatives were

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6

Abd El-Aal, Hassan A. K., and Ali A. Khalaf. "Friedel–Crafts Chemistry. Part 46. Unprecedented Construction of Tricyclic Pyrazolo[3,4-b]quinolines, -[1,8]naphthyridines, -azepines, -azocines, -pyrido[3,2-g]azocines, and pyrazolo[3,4-b]azonines via Friedel–Crafts Ring Closures." Australian Journal of Chemistry 69, no. 6 (2016): 652. http://dx.doi.org/10.1071/ch15526.

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A series of keto-substituted pyrazolo[3,4-b]quinolines, pyrazolo[3,4-b][1,8]naphthyridines, benzo[e]pyrazolo[3,4-b]azepines, benzo[g]pyrazolo[3,4-b]azocines, pyrazolo[3,4-b]pyrido[3,2-g]azocines, and benzo[g]pyrazolo[3,4-b]azonines scaffolds were synthesized via a Friedel–Crafts cyclialkylation approach. The precursor acids were obtained by utilizing the modified Ullman coupling reactions of 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid with different aryl amines followed by ring closures in the presence of AlCl3/CH3NO2 or P2O5 or polyphosphoric acid catalysts. Particular attention

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7

Taherkhorsand, Hasti, and Mohammad Nikpassand. "One-pot Synthesis of Novel 2-pyrazolo-3-phenyl-1,3-thiazolidine-4-ones Using DSDABCOC as an Effective Media." Combinatorial Chemistry & High Throughput Screening 21, no. 1 (2018): 65–69. http://dx.doi.org/10.2174/1386207321666180124094055.

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Background: Thiazolidine compounds are known to show interesting pharmacological activity. In particular, they are used as antiseizure, fungicidal, anti-bacterial, antitubercular, antiinflammatory, antiamoebic, anti-diabetic and local anesthetic agents. Some of these compounds have also shown antiparkinsonism, antioxidant, anticonvulsant, hypoglycemic and non-narcotic analgesic activities. On the other hand, pyrazoles have shown antibacterial, antitumor, antiviral, antifungal, anti-tubercular, antiparasitic, anesthetic, anti-diabetic, anti-inflammatory, analgesic and insecticidal activities. I

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8

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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9

Archana, Sreeramapura D., Channappa N. Kavitha, Hemmige S. Yathirajan, Sabine Foro, and Christopher Glidewell. "Two 3-amino-1H-pyrazol-2-ium salts containing organic anions, and an orthorhombic polymorph of 3-amino-1H-pyrazol-2-ium nitrate." Acta Crystallographica Section E Crystallographic Communications 77, no. 1 (2021): 34–41. http://dx.doi.org/10.1107/s2056989020015959.

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Co-crystallization from methanol of 3-amino-1H-pyrazole with 3,5-dinitrobenzoic acid produces 3-amino-1H-pyrazol-2-ium 3,5-dinitrobenzoate monohydrate, C3H6N3 +·C7H3N2O6 −·H2O, (I), while similar co-crystallization of this pyrazole with an equimolar quantity of fumaric acid produces bis(3-amino-1H-pyrazol-2-ium) fumarate–fumaric acid (1/1), 2C3H6N3 +·C4H2O4 2−·C4H4O4, (II). The reaction of 3-amino-1H-pyrazole with a dilute solution of nitric acid in methanol yields a second, orthorhombic polymorph of 3-amino-1H-pyrazol-2-ium nitrate, C3H6N3 +·NO3 −, (III). In each of (I)–(III), the bond distan

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10

Zhang, Furen, Chunmei Li, and Chenze Qi. "Synthesis of 4,8-dihydro-1H-pyrazolo[3,4-e][1,4]thiazepin-7(6H)-one derivatives by solid acid-catalyzed multi-component reaction in water." RSC Advances 6, no. 105 (2016): 102924–30. http://dx.doi.org/10.1039/c6ra24310j.

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A solid acid is found to efficiently catalyze the condensation of substituent-pyrazoles, aldehydes, and thioglycollic acid to afford a wide range of pyrazolo[3,4-e][1,4]thiazepine derivatives with good to excellent yields.

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11

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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12

Erdem, Ahmet, Hasan Genc, Nejdet Sen, Rafet Kilincarslan, and Emin Erdem. "The Synthesis and Reactions of Novel Pyrazole Derivatives by 4-phenylcarbonyl-5-phenyl-2,3-dihydro-2,3-furandione Reacted with Some Hydrazones." Revista de Chimie 68, no. 1 (2017): 143–46. http://dx.doi.org/10.37358/rc.17.1.5407.

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We report some novel pyrazole derivatives taking 4-phenylcarbonyl-5-phenyl-2,3-dihydro-2,3-furandione, 1. For this, 4-phenylcarbonyl-5-phenyl-2,3-dihydro-2,3-furandione, 1 was reacted with benzaldehyde(2- or 4-fluorophenyl)hydrazone to give 4-benzoyl-1-(2- or 4-fluorophenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid 2a,b. Pyrazol derivative containing 2-fluorophenyl group 2a was converted into carboxylic chloride derivative 3a by thionyl chloride and then the compound 4a was obtained from reaction ammonia with compound 3a. In the next step, 4-benzoyl-1-(2-fluorophenyl)-5-phenyl-1H-pyrazole-3-carb

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13

Nurlaili, Jasril, and Hilwan Yuda Teruna. "UJI AKTIVITAS ANTIOKSIDAN SENYAWA PIRAZOLIN 3-(2- METOKSI-FENIL)-5-NAFTALEN-1-IL-4,5-DIHIDRO-1H-PIRAZOL." Photon: Jurnal Sain dan Kesehatan 8, no. 2 (2018): 53–58. http://dx.doi.org/10.37859/jp.v8i2.716.

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Pyrazoline compounds are reported to have many useful biological activities such as antimicrobials, antihyperglycemia, antioxidants, anti-inflammatory, anticancer and anticonvulsants. The pyrazoline analogues of 3- (2-methoxy-phenyl) -5-naphthalene-1-yl-4,5-dihydro-1H-pyrazol were synthesized usingglacial acetic acid as catalyst and assisted by microwave irradiation. The structures of the compounds were obtainedby UV, IR and HRMS spectroscopy data. Antioxidant activity test using DPPH method showed that pyrazoline compound had IC50 value of 27.41 μg/mL.

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14

Norman, Rebecca E., Michael V. Perkins, Andris J. Liepa, and Craig L. Francis. "N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XIII. Cleavage and Rearrangement Reactions of Pyrazolo[1,5-b][1,2,4,6]thiatriazine 1,1-Dioxides." Australian Journal of Chemistry 69, no. 1 (2016): 61. http://dx.doi.org/10.1071/ch15445.

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Treatment of pyrazolo[1,5-b][1,2,4,6]thiatriazines 1 with the Vilsmeier–Haack reagent afforded pyrazolo[1,5-a][1,3,5]triazines 5. Reaction of compounds 1 with trifluoroacetic anhydride, dimethyl sulfoxide, and triethylamine afforded 5-dimethylsulfanylidene derivatives 8. The guanidino-pyrazole-sulfonic acid 9 was produced from treatment of compounds 1 with trifluoroacetic acid under anhydrous conditions. Similar treatment in the presence of water afforded the desulfonated pyrazolo-guanidine 6. Reactions of 6 with one-carbon electrophiles provided various 4-substituted pyrazolo[1,5-a][1,3,5]tri

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15

Mcfadden, HG, and JL Huppatz. "Synthesis of (Pyrazol-4-yl)alkanones and Alkylpyrazole-4-Carbonitriles." Australian Journal of Chemistry 44, no. 9 (1991): 1263. http://dx.doi.org/10.1071/ch9911263.

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1-(5-Aminopyrazol-4-yl)alkan-1-ones and 5-alkylpyrazole-4-carbonitriles were obtained by reaction of 2-(1-ethoxyalkylidene)-3-oxoalkanenitriles (acrylonitriles) with hydrazines. The ratios of the various pyrazole products depended on the solvent used, and on the nature of the substituents on both the acrylonitrile and hydrazine reactants. In general, formation of pyrazole-4-carbonitriles was favoured by the use of acetic acid whereas use of ethanol favoured the formation of 1-(pyrazol-4-yl)alkan-1-ones. The use of 3-ethylacrylonitrile gave predominantly 3-ethylpyrazole-4-carbonitriles whereas

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16

Schmidt, Arthur H., Timo Schreck, Ralf Rötz, and Sarah von Freytag-Loringhoven. "Oxokohlenstoffe und verwandte Verbindungen, 30 [1]. Über die Umsetzung von Quadratsäure mit Pyrazolinonen / Oxocarbons and Related Compounds, 30 [1]. On the Reaction of Squaric Acid with Pyrazolinones." Zeitschrift für Naturforschung B 61, no. 3 (2006): 311–19. http://dx.doi.org/10.1515/znb-2006-0311.

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Abstract Heating of squaric acid (1) with the 1-aryl-3-methyl-5-oxo-2,5-dihydro-1H-pyrazoles 3a - j and the 1,3-disubstituted pyrazolinones 7a - d in the molar ratio of 1:2 in a mixture of n-BuOH/toluene afforded the bis(pyrazolyl)-squaraines 4a - j and 8a - d, respectively. Reaction of an excess of 1 with the pyrazolinone 3j yielded 4j and the 3-hydroxy-4-pyrazolyl-cyclobutene-1,2-dione 6 as a byproduct. In contrast to disubstituted pyrazolinones, the trisubstituted pyrazolinones 9a - e reacted with squaric acid (1) to give the hydroxy-oxopyrazolyl-cyclobutenediones 10a - e.

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17

Altıntop, Mehlika Dilek. "Synthesis, In vitro and In silico Evaluation of a Series of Pyrazolines as New Anticholinesterase Agents." Letters in Drug Design & Discovery 17, no. 5 (2020): 574–84. http://dx.doi.org/10.2174/1570180816666190618111023.

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Background: Pyrazolines, electron-rich nitrogen carriers, are of great importance due to their potential applications for the treatment of many diseases including inflammation, infectious diseases and neurodegenerative disorders. Objectives: The purpose of this work was to synthesize new pyrazoline derivatives and evaluate their anticholinesterase effects. Methods: 1-Aryl-5-[4-(piperidin-1-yl)phenyl]-3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazoles (1-7) were synthesized via the treatment of 1-(3,4-dimethoxyphenyl)-3-[4-(piperidin-1-yl)phenyl]prop-2- en-1-one with arylhydrazine hydrochloride d

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18

Girisha, Marisiddaiah, Hemmige S. Yathirajan, Jerry P. Jasinski, and Christopher Glidewell. "Different acid–base behaviour of a pyrazole and an isoxazole with organic acids: crystal and molecular structures of the salt 3-(4-fluorophenyl)-1H-pyrazolium 2,4,6-trinitrophenolate and of the cocrystal 4-amino-N-(3,4-dimethyl-1,2-oxazol-5-yl)benzenesulfonamide–3,5-dinitrobenzoic acid (1/1)." Acta Crystallographica Section C Structural Chemistry 72, no. 8 (2016): 612–18. http://dx.doi.org/10.1107/s2053229616010494.

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Pyrazole and isoxazole rings differ only in the notional replacement of a potential hydrogen-bond-donor NH unit in pyrazole by a potential hydrogen-bond-acceptor O atom in isoxazole. It is thus of interest to compare the hydrogen-bonding characteristics of these rings. (4-Fluorophenyl)pyrazole undergoes protonation in the presence of 2,4,6-trinitrophenol to yield the salt 3-(4-fluorophenyl)-1H-pyrazolium 2,4,6-trinitrophenolate, C9H8FN2+·C6H2N3O7−, (I), whereas there is no proton transfer between 4-amino-N-(3,4-dimethyl-1,2-oxazol-5-yl)benzenesulfonamide and 3,5-dinitrobenzoic acid, whose reac

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19

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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20

Deepa, M., V. Harinadha Babu, R. Parameshwar, and B. Madhava Reddy. "Synthesis of 3-(1, 3-Diphenyl-1H-pyrazol-4-yl) Propanoic Acids Using Diimide Reduction." E-Journal of Chemistry 9, no. 1 (2012): 420–24. http://dx.doi.org/10.1155/2012/481682.

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Pyrazole-1H-4-yl-acrylic acids (3a-j) were prepared from pyrazole-1H-4-carbaldehydes which in turn were prepared by the Vilsmeier-Haack reaction of phenyl hydrazone derivatives (1a-j). The reaction of pyrazole-1H-4-yl-acrylic acids to 3-(1, 3-diphenyl-1H-pyrazol-4-yl) propanoic acids (4a-j) was carried out using Pd-charcoal and diimide methods and % yields were compared. Though the yields may be slightly less in diimide method, the method was found to be economical, highly effective with simple operating procedure.

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21

Abd El-Aal, Hassan A. K., and Talaat I. El-Emary. "Synthesis of Tetracyclic Fused Quinolines via a Friedel–Crafts and Beckmann Ring Expansion Sequence." Australian Journal of Chemistry 72, no. 12 (2019): 945. http://dx.doi.org/10.1071/ch19363.

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An efficient protocol for the construction of tetracyclic fused quinolines (pyrazole-fused azepino-, azocino-, and azonino[3,2-b]quinolinones) via consecutive Friedel–Crafts and Beckmann reactions has been developed. The key steps in the syntheses of these new molecular scaffolds involve acid-mediated cyclization of 2-(pyrazol-3-yl)quinoline based carboxylic acids 6a–c, 8, and 12 to ketones 13a–e, followed by Beckmann rearrangements of the corresponding oximes 14a–e to provide the tetracyclic-fused quinoline skeletons 15a–e. Structures of synthesised compounds without stereochemical implicatio

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22

Abd El-Aal, Hassan A. K., and Talaat I. El-Emary. "Corrigendum to: Synthesis of Tetracyclic Fused Quinolines via a Friedel–Crafts and Beckmann Ring Expansion Sequence." Australian Journal of Chemistry 72, no. 12 (2019): 990. http://dx.doi.org/10.1071/ch19363_co.

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An efficient protocol for the construction of tetracyclic fused quinolines (pyrazole-fused azepino-, azocino-, and azonino[3,2-b]quinolinones) via consecutive Friedel–Crafts and Beckmann reactions has been developed. The key steps in the syntheses of these new molecular scaffolds involve acid-mediated cyclization of 2-(pyrazol-3-yl)quinoline based carboxylic acids 6a–c, 8, and 12 to ketones 13a–e, followed by Beckmann rearrangements of the corresponding oximes 14a–e to provide the tetracyclic-fused quinoline skeletons 15a–e. Structures of synthesised compounds without stereochemical implicatio

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23

Zhang, Mo, Peng Liu, Yu-Heng Liu, Ze-Ren Shang, Hai-Chuan Hu, and Zhan-Hui Zhang. "Magnetically separable graphene oxide anchored sulfonic acid: a novel, highly efficient and recyclable catalyst for one-pot synthesis of 3,6-di(pyridin-3-yl)-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles in deep eutectic solvent under microwave irradiation." RSC Advances 6, no. 108 (2016): 106160–70. http://dx.doi.org/10.1039/c6ra19579b.

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A magnetic separable sulfonic acid catalyst was prepared and applied for the synthesis of 3,6-di(pyridin-3-yl)-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles via three-component reaction of 1-phenyl-3-(pyridin-3-yl)-1H-pyrazol-5-amine, β-ketonitrile and aldehydes in DES.

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24

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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25

Kasimogullari, Rahmi, Belma Zengin, Makbule Maden, Samet Mert, and Cavit Kazaz. "Synthesis of new derivatives of 1-(3-amino-phenyl)-4- benzoyl-5-phenyl-1h-pyrazole-3-carboxylic acid." Journal of the Serbian Chemical Society 75, no. 12 (2010): 1625–35. http://dx.doi.org/10.2298/jsc101018135k.

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4-Benzoyl-1-(3-aminophenyl)-5-phenyl-1H-pyrazole-3- carboxylic acid (1) was synthesized according to the literature.1 2-(3- Aminophenyl)-3,4-diphenyl-2H-pyrazolo[3,4-d]pyridazin-7(6H)-one (5) was obtained by the cyclocondensation reaction of 1 with hydrazine hydrate. New pyrazole derivatives of compounds 1 and 5 were synthesized by their reaction with ?-diketones, ?-ketoesters, ?-naphthol, phenol and various other reagents. The structures of the synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR and Mass spectroscopy, as well as elemental analysis.

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26

Sofei, Maria-Daniela, Maria Ilici, Valentin Badea, Carol Csunderlik, and Vasile-Nicolae Bercean. "Synthesis and Caracterization of some New 1H-3-aryl-7-etoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles." Revista de Chimie 59, no. 1 (2008): 41–44. http://dx.doi.org/10.37358/rc.08.1.1703.

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The synthesis of 1H-3-aryl-7-ethoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles (2) was carried out by cyclization of 1H-5-arylidenehydrazino-4-ethoxycarbonyl-3-methyl-pyrazoles (1) in the presence of bromine using glacial acetic acid as solvent and sodium acetate as base. The new nine obtained compounds were characterized by IR and NMR spectroscopy and mass spectrometry.

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27

Chovatia, P. T., J. D. Akabari, P. K. Kachhadia, P. D. Zalavadia, and H. S. Joshi. "Synthesis and selective antitubercular and antimicrobial inhibitory activity of 1-acetyl-3,5-diphenyl-4,5-dihydro-(1h)-pyrazole derivatives." Journal of the Serbian Chemical Society 71, no. 7 (2006): 713–20. http://dx.doi.org/10.2298/jsc0607713c.

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The new compounds 1-aryl-3-{1-phenyl-3-[p (methylthio)phenyl]pyrazol-4-yl}-2-propen-1-ones 2a?l were prepared by the condensation of 1-phenyl-3-[p (methylthio)phenyl]-4-formylpyrazole 1 with different aryl ketones. Compounds 2a?l in reaction with hydrazine hydrate yielded 3-aryl-5-{1-phenyl-3-[p-(methylthio)phenyl]pyrazol-4 yl}-4,5-dihydro-(1H)-pyrazoles 3a?l and in the presence of hydrazine hydrate in glacial acetic acid gave 1-acetyl-3-aryl 5-{1-phenyl-3-[p-(methylthio)phenyl]pyrazol-4-yl}-4,5 dihydro-(1H)-pyrazoles 4a?l. These compounds were tested in vitro for their antitubercular and anti

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28

Rádl, Stanislav. "Preparation of Some Pyrazole Derivatives by Extrusion of Elemental Sulfur from 1,3,4-Thiadiazines." Collection of Czechoslovak Chemical Communications 57, no. 3 (1992): 656–59. http://dx.doi.org/10.1135/cccc19920656.

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In connection with our research of pyrazolo[3,4-b]quinolines we were also interested in the preparation of various pyrazole intermediates. In some cases we found a method useful based on extrusion of elemental sulfur from intermediate 1,3,4-thiadiazines. This short contribution describes the preparation of some new 3-anilino-4-pyrazolecarboxylic acid derivatives using this method.

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29

Dinoiu, Vasile, and Jian-Ming LÜ. "Synthesis of new trifluoromethyl-containing 1-(3,5-dialkyl-4-hydroxybenzyl)-pyrazole and -pyrazol-5-one deriatives and their corresponding aroxyls." Journal of the Serbian Chemical Society 71, no. 4 (2006): 323–30. http://dx.doi.org/10.2298/jsc0604323d.

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3,5-Dialkyl-4-hydroxybenzylhydrazine 1 reacted with hexafluoroacetylacetone and trifluoroacetylacetone yielding the pyrazoles 2 bearing trifluoromethyl and/or methyl substituents in positions 3 and 5. The same hydrazine derivatives 1 afforded the pyrazol-5-ones 3 with trifluoroacetoacetic acid ethyl ester. On oxidation with lead tetraacetate in CH2Cl2, some stable aroxyls were obtained and their ESR spectra are described.

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30

Hussain, Zahid, Cristiane Schwalm, Raoní Rambo, Renieidy Dias, Rafael Stieler, and Adriano Monteiro. "Synthesis of Mono- and Bis-Pyrazoles Bearing Flexible p-Tolyl Ether and Rigid Xanthene Backbones, and Their Potential as Ligands in the Pd-Catalysed Suzuki–Miyaura Cross-Coupling Reaction." Catalysts 9, no. 9 (2019): 718. http://dx.doi.org/10.3390/catal9090718.

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The present work describes the synthesis of mono- and bis-pyrazole compounds bearing flexible p-tolyl ether and rigid 4,5-dibromo-2,7-di-tert-butyl-9,9-dimethyl-9H-xanthene backbones as pyrazolyl analogues of DPEphos and Xantphos ligands, respectively. The synthesis of new pyrazolyl analogues was accomplished following an Ullmann coupling protocol, and the resulting products were isolated in overall good yields. In addition, a hybrid imidazolyl–pyrazolyl analogue bearing a xanthene backbone was synthesized using the same protocol, whereas a hybrid selanyl–pyrazolyl analogue with a xanthene bac

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31

Jasril, Jasril, Hilwan Yuda Teruna, Aisyah Aisyah, Nurlaili Nurlaili, and Rudi Hendra. "Microwave Assisted Synthesis and Evaluation of Toxicity and Antioxidant Activity of Pyrazoline Derivatives." Indonesian Journal of Chemistry 19, no. 3 (2019): 583. http://dx.doi.org/10.22146/ijc.34285.

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Four pyrazoline analogues, 3-(4-methoxyphenyl)-5-naphthalene-1-yl-1-phenyl-4,5-dihydro-pyrazole (3), 3-(4-methoxyphenyl)-5-naphthalene-1-yl-4,5-dihydro-1H-pyrazole (4), 3-(2-methoxyphenyl)-5-naphthalene-1-yl-1-phenyl-4,5-dihydro-pyrazole (5) and 3-(2-methoxyphenyl)-5-naphthalene-1-yl-4,5-dihydro-1H-pyrazole (6) were synthesized via intermolecular cyclization between substituted chalcones and hydrazine derivatives. The compounds were synthesized in two steps. In the first step, the chalcones were synthesized by Claisen-Schmidt reaction. In the second step, they were cyclized with some hydrazine

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32

Herfindo, Noval, Riska Prasetiawati, Daniel Sialagan, Neni Frimayanti та Adel Zamri. "Synthesis, Antiproliferative Activity and Molecular Docking Studies of 1,3,5-Triaryl Pyrazole Compound as Estrogen α Receptor Inhibitor Targeting MCF-7 Cells Line". Molekul 15, № 1 (2020): 18. http://dx.doi.org/10.20884/1.jm.2020.15.1.585.

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This research has been successfully synthesized three compounds of 1,3,5-triaryl pyrazole derivatives by two steps reaction. Firstly, pyrazoline (4a-c) compound was obtained by one-pot reaction of aromatic ketones, aldehyde and hydrazine in basic condition. Then, pyrazole (5a-c) compound was obtained by oxidative aromatization of compound 4 in the presense of acetic acid. Chemical structure of predicted molecules was confirmed by FTIR, NMR and HRMS spectroscopy data analysis. Antiproliferative activity of compound 5a-c were evaluated by in vitro assay against MCF-7 cells line and molecular doc

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33

Safieh, Kayed A. Abu, Feda’a S. Al-Masri, Mikdad T. Ayoub, Mustafa M. El-Abadelah, and Wolfgang Voelter. "Synthesis of Some 1,3-Dimethyl-6-substituted-1H-pyrazolo[3,4-b]pyrazin-5(4H)-ones." Zeitschrift für Naturforschung B 66, no. 11 (2011): 1136–40. http://dx.doi.org/10.1515/znb-2011-1109.

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A series of new 6-substituted-1,3-dimethyl-1H-pyrazolo[3,4-b]pyrazin-5(4H)-ones (13a - e) and 1,3-dimethyl-5a,6a,7,8-tetrahydro-1H-pyrazolo[4,3-e]pyrrolo[1,2-a]pyrazin-5(4H)-one (15) have been synthesized. The synthetic strategy involves direct interaction of D,L-α-amino acids with 5- chloro-1,3-dimethyl-4-nitro-1H-pyrazole (10) to produce the respective N-(1,3-dimethyl-4-nitro-1Hpyrazol- 5-yl) D,L-α-amino acids 11a - e and 14. The latter compounds underwent reductive lactamization to deliver the corresponding target heterocyclic systems 13a - e and 15

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34

Burlutskiy, Nikita P., and Andrei S. Potapov. "Approaches to the Synthesis of Dicarboxylic Derivatives of Bis(pyrazol-1-yl)alkanes." Molecules 26, no. 2 (2021): 413. http://dx.doi.org/10.3390/molecules26020413.

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Carboxylation of bis(pyrazol-1-yl)alkanes by oxalyl chloride was studied. It was found that 4,4′-dicarboxylic derivatives of substrates with electron-donating methyl groups and short linkers (from one to three methylene groups) can be prepared using this method. Longer linkers lead to significantly lower product yields, which is probably due to instability of the intermediate acid chlorides that are initially formed in the reaction with oxalyl chloride. Thus, bis(pyrazol-1-yl)methane gave only monocarboxylic derivative even with a large excess of oxalyl chloride and prolonged reaction duration

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35

Matulevičiūtė, Gita, Eglė Arbačiauskienė, Neringa Kleizienė, et al. "Synthesis and Characterization of Novel Methyl (3)5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates." Molecules 26, no. 13 (2021): 3808. http://dx.doi.org/10.3390/molecules26133808.

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Series of methyl 3- and 5-(N-Boc-piperidinyl)-1H-pyrazole-4-carboxylates were developed and regioselectively synthesized as novel heterocyclic amino acids in their N-Boc protected ester form for achiral and chiral building blocks. In the first stage of the synthesis, piperidine-4-carboxylic and (R)- and (S)-piperidine-3-carboxylic acids were converted to the corresponding β-keto esters, which were then treated with N,N-dimethylformamide dimethyl acetal. The subsequent reaction of β-enamine diketones with various N-mono-substituted hydrazines afforded the target 5-(N-Boc-piperidinyl)-1H-pyrazol

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36

Journal, Baghdad Science. "Synthesis of New Pyrazoline - Phenoxathiin Derivatives." Baghdad Science Journal 10, no. 2 (2013): 405–19. http://dx.doi.org/10.21123/bsj.10.2.405-419.

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Phenoxathiin was prepared by the reaction of diphenyl ether with sulfur in the presence of anhydrous aluminum chloride. This work comprised the synthesis of new phenoxathiin derivatives containing heterocyclic moieties. These heterocyclic compounds were synthesized in three groups. The first group was made up of 2-(oxoalken-1-yl) phenoxathiin derivatives (3a-3j) obtained from the reaction of 2-acetylphenoxathiin with different aromatic aldehyde in the presence of sodium hydroxide. The other two groups involved compounds produced from the reaction of (3a-3j) with hydrazine hydrate in acetic aci

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37

Zaderenko, P., M. S. Gil, P. López, P. Ballesteros, I. Fonseca, and A. Albert. "Diethyl 2-Benzimidazol-1-ylsuccinate–Picric Acid (1/1) – An Inclusion Molecular Complex." Acta Crystallographica Section B Structural Science 53, no. 6 (1997): 961–67. http://dx.doi.org/10.1107/s0108768197008562.

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The crystal structure of the diethyl 2-benzimidazol-1-ylsuccinate–picric acid (1/1) molecular complex has been determined by X-ray diffraction analysis. Diethyl 2-benzimidazol-l-ylsuccinate molecules form channels along the a axis, in which the picric acid molecules are located. The benzimidazole moiety and the phenol group are held together by hydrogen bonding between the hydrogen of the phenol and the N3 atom of benzimidazole. Additionally, this hydrogen forms an intramolecular hydrogen bond with one O atom of the ortho-nitro group, thus producing a bifurcated hydrogen bond. 1H NMR spectra i

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38

Venkata Narsimha Reddy, Chintalapani, Eligeti Rajanarendar, and Ananthula Krishnamurthy. "Synthesis of 3-methyl-1,5-diphenyl-7-aryl-7,8-dihydro-6H-pyrazolo[4,5-b]azepines." Collection of Czechoslovak Chemical Communications 55, no. 4 (1990): 1055–58. http://dx.doi.org/10.1135/cccc19901055.

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3,5-Dimethyl-4-nitro-1-phenylpyrazole (I) on treatment with chalcones II under phase transfer conditions gives the Michael adducts, 3-methyl-4-nitro-1-phenyl-5-(2-aryl-4-phenyl-4-oxo-1-butyl)pyrazoles (III). The Michale adducts on cycloreduction with stannous chloride-hydrochloric acid furnish 3-methyl-1,5-diphenyl-7-aryl-7,8-dihydro-6H-pyrazolo[4,5-b]azepines (IV). IR, 1H NMR, 13C NMR and mass spectra support the structures of III and IV.

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39

Bustos, Carlos, Luis Alvarez-Thon, Tania Oportus, Angela Mesías-Salazar, and Ricardo Baggio. "On substituted pyrazole derivatives. II. (E)-1-(4-{[1-(4-Fluorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone and (E)-1-(4-chlorophenyl)-3,5-dimethyl-4-[2-(2-nitrophenyl)diazenyl]-1H-pyrazole." Acta Crystallographica Section C Structural Chemistry 71, no. 1 (2015): 53–58. http://dx.doi.org/10.1107/s2053229614024619.

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The molecular structures of (E)-1-(4-{[1-(4-fluorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl]diazenyl}phenyl)ethanone, C19H17FN4O, (III), and (E)-1-(4-chlorophenyl)-3,5-dimethyl-4-[2-(2-nitrophenyl)diazenyl]-1H-pyrazole, C17H14ClN5O2, (IV), prepared by reaction of the corresponding β-diketohydrazones with substituted arylhydrazines in acid media, are nonplanar, with the planes of the lateral phenyl rings forming dihedral angles with that of the central pyrazole ring varying from 2.71 (7) to 45.22 (7)°. The crystal structures are supported by C—H...O, C—H...π and π–π weak intermolecular interactions

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40

Li, Yi, Yuan-Yuan Liu, Xiao-Hui Xiong, and Ping Wei. "2-(1,5-Diphenyl-1H-pyrazol-3-yloxy)-1-(2-sulfanylidene-1,3-thiazolidin-3-yl)ethanone." Acta Crystallographica Section E Structure Reports Online 68, no. 8 (2012): o2419. http://dx.doi.org/10.1107/s1600536812029959.

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The title compound, C20H17N3O2S2, was synthesized by the reaction of 2-(1,5-diphenyl-1H-pyrazol-3-yloxy)acetic acid and thiazolidine-2-thione. The C-linked benzene ring, N-linked benzene ring and thiazolidine-2-thione ring are twisted 31.33 (2), 62.87 (1) and 82.71 (2)°, respectively, from the plane of the bridging 1H-pyrazole ring. The phenyl rings are oriented at a dihedral angle of 72.16 (2)°.

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41

Lynda, Golea. "Synthesis, DFT, Molecular docking Analysis and Antibacterial, Antioxidant Activities of tri-substituted pyrazoles." ASM Science Journal 16 (July 15, 2021): 1–7. http://dx.doi.org/10.32802/asmscj.2021.696.

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Pyrazole and its derivatives are contemplated crucial compounds in heterocyclic chemistry which are also used extensively in organic synthesis. These cycles are known for their biological and pharmacological activities. The present investigation is in the interest of some synthesized derivatives containing the pyrazole moieties. (5-Hydroxy-3,5-dimethyl-4,5-dihydro-pyrazol-1-yl)-pyridin-4-yl-methanone (1) and Furan-2-yl-(5-hydroxy-3,5-dimethyl-4,5-dihydro-pyrazol-1-yl)-methanone (2) were synthesized by cyclocondensation of the 1,3-dicarbonyl with the hydrazine derivative with a simple and rapid

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42

Kantlehner, Willi, Jochen Mezger, Rüdiger Stieglitz, et al. "Orthoamide, LXV [1]. Kondensationsreaktionen von Amidinen, Guanidinen, Hydrazin und Hydrazin-Derivaten mit Orthoamiden von Alkincarbonsäuren / Orthoamides,LXV [1]. Condensation Reactions of Amidines, Guanidines, Hydrazine and Hydrazine Derivatives with Orthoamides of Alkyne Carboxylic Acids." Zeitschrift für Naturforschung B 62, no. 8 (2007): 1015–29. http://dx.doi.org/10.1515/znb-2007-0804.

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The orthoamide derivatives 4 react with amidines 10 and guanidines 11 to give 4-dimethylaminopyrimidines 12. The 3-dimethylamino-pyrazoles 13a - c can be prepared from orthoamides 4 and hydrazine. The hydrazine derivative 14, whose constitution was established by crystal structure analysis, is obtained in low yield when hydrazine is added dropwise to a boiling solution of 4d in THF.Methyl- and phenylhydrazine, undergo reaction with the orthoamides 4a, c yielding mixtures of the isomeric pyrazoles 19 and 20. The reaction of 4c with acylhydrazines 21a - e affords the pyrazole 13b. The pyrazole 2

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43

El-Ossaily, Y. A. B., R. M. Zaki, and S. A. Metwally. "Investigation and Synthesis of Some Novel Spiro Heterocycles Related to Indoline Moiety." Journal of Scientific Research 6, no. 2 (2014): 293–307. http://dx.doi.org/10.3329/jsr.v6i2.17590.

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Reactions of indole-2,3-dione 1 with 2-mercaptobenzimidazole, o-phenylenediamine, 2-aminophenol, 2-aminobenzothiazole, 2-aminobenzimidazole and 3-methyl-1-phenyl-2-pyrazolin-5-one were carried out to give compounds spiroindolethiazetobenzimidazole 2, spirobenzimidazole(oxazole)indoline 3a,b, benzothiazol(imidazol) iminoindolinone 4a,b and methyloxoindolylidenepyrazolone 5 respectively. Compound 5 was reacted with 2-aminophenol as well as o-phenylenediamine to give new spirooxazepine and diazepine derivatives 6a,b respectively. Reaction of 5 with nitrogen nucleophiles as well as carbon nucleoph

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44

Hrynyshyn, Yevhenii, Hanna Musiichuk, Olena Komarovska-Porokhnyavets, et al. "Synthesis and Antimicrobial Activity of 4-Arylthio- and 4 Alkylthiofunctionalized Pyrazolo[1,5-a]pyrazines." Ukrainian Chemistry Journal 85, no. 1 (2019): 58–66. http://dx.doi.org/10.33609/0041-6045.85.1.2019.58-66.

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The reaction of pyrazolo[1,5-a]pyrazine-4(5H)ones with phosphorus tribromoxide in boiling benzene yielded 4-bromopyrazolo[1,5-a]pyrazines, and the thionation with phosphorus pentasulfide in pyridine at 90 °C led to pyrazolo[1,5-a]pyrazine-4(5H)thiones. The synthesized bromine derivatives are electrophilic, and thiones are nucleophilic substrates. Their subsequent structural modification in the first case was carried out by interaction with thiophenols, and in the second case was conducted with functional halogenoalkanes. It was shown that bromides react with substituted thiophenols in dimethyl

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45

Sikandar, Sana, Ameer Fawad Zahoor, Sajjad Ahmad, Muhammad Naveed Anjum, Mirza Nadeem Ahmad, and Muhammad Sami Ullah Shah. "L-Cysteine Catalyzed Environmentally Benign One-pot Multicomponent Approach Towards the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives." Current Organic Synthesis 17, no. 6 (2020): 457–63. http://dx.doi.org/10.2174/1570179417666200511092332.

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Background: The pyrano[2,3-c]pyrazole derivatives are important building blocks of many biologically active compounds owing to their diverse biological potential for example, anti-inflammatory, anticancer, anti-microbial and anti-oxidant properties. Objective: Keeping in mind the wide range of applications of pyrano[2,3-c]pyrazoles, herein we intended to develop a novel synthetic methodology for dihydropyranopyrazoles. We were also interested in determining the influence of amino acids and dipeptides as a catalyst on the synthesis of pyrano[2,3-c]pyrazole derivatives. Methods: To achieve our o

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46

Butković, Kristina, Željko Marinić, Krešimir Molčanov, Biserka Kojić-Prodić, and Marija Šindler-Kulyk. "Photochemical and thermal intramolecular 1,3-dipolar cycloaddition reactions of new o-stilbene-methylene-3-sydnones and their synthesis." Beilstein Journal of Organic Chemistry 7 (December 13, 2011): 1663–70. http://dx.doi.org/10.3762/bjoc.7.196.

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New trans- and cis-o-stilbene-methylene-sydnones 3a,b were synthesized by transforming the trans- and cis-o-aminomethylstilbene derivative, obtained by reduction of corresponding o-cyano derivatives, into glycine ester derivatives (43 and 31% yield) followed by hydrolysis (90 and 96% yield), nitrosation and ring closure with acetic acid anhydride (30 and 40% yield). The products were submitted to photochemical and thermal intramolecular [3 + 2] cycloadditions to afford diverse heteropolycyclic compounds. Photochemical reactions afforded cis-3-(4-methylphenyl)-3a,8-dihydro-3H-pyrazolo[5,1-a]iso

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47

Thokchom, Herojit S., Anita D. Nongmeikapam, and Warjeet S. Laitonjam. "Synthesis of fused pyrazolo-, isoxazolo-, pyrimido-, and pyridopyrimidines." Canadian Journal of Chemistry 83, no. 8 (2005): 1056–62. http://dx.doi.org/10.1139/v05-054.

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A systematic study of the synthesis of the 5,7-diaryl-4-oxo-pyrazolo[3,4-d]pyrimidin-6-thiones (3), 2-phenyl-5,7-bis(2′-methylphenyl)-4-oxo-pyrazolo[3,4-d]pyrimidin-6-thiones (4b), 2(3H)-3-phenyl-5,7-diaryl-4-oxo-pyrazolo[3,4-d]pyrimidin-6-thiones (5), 5,7-diaryl-4-oxo-isoxazolo[5,4-d]pyrimidin-6-thiones (7), 3,5,7-triaryl-2,3-dihydro-4-oxo-isoxazalo[5,4-d]pyrimidin-6-thiones (8), 2-amino-6,8-diaryl-5-oxo-pyrimido[4,5-d]pyrimidin-7-thiones (9), 3,4-dihydro-2-amino-4-phenyl-6,8-diaryl-5-oxo-pyrimido[4,5-d]pyrimidin-7-thiones (10), 3-cyano-6,8-diaryl-2,5-dioxo-pyrido[2,3-d]pyrimidin-7-thiones (1

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48

Vora, J. J., S. B. Vasava, K. C. Parmar, S. K. Chauhan, and S. S. Sharma. "Synthesis, Spectral and Microbial Studies of Some Novel Schiff Base Derivatives of 4-Methylpyridin-2-amine." E-Journal of Chemistry 6, no. 4 (2009): 1205–10. http://dx.doi.org/10.1155/2009/247209.

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Schiff base derivatives ofN-{(1E)-[3-(mono or di-substituted aryl)-1-phenyl-1H-pyrazol-4-yl]methylene{-4-methylpyridin-2-amine were synthesized by the acid catalyzed condensation of 3-(mono- or di- substituted aryl)-1-phenyl-1H-pyrazole-4-carbaldehyde derivatives with 4-methylpyridin-2-amine. Schiff base derivatives were characterized by FT-IR,1H-NMR, Mass spectral analysis and elemental analysis. All the synthesized compounds have been screened for their antimicrobial activities by using broth dilution method.

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49

Tan, Zheng-De, Feng-Jiao Tan, Bo Tan, and Cheng-Ming Zhang. "4-(1H-Pyrazol-3-yl)pyridine–terephthalic acid–water (2/1/2)." Acta Crystallographica Section E Structure Reports Online 68, no. 6 (2012): o1942. http://dx.doi.org/10.1107/s1600536812021599.

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In the title compound, 2C8H7N3·C8H6O4·2H2O, the pyridine and pyrazole rings are approximately coplanar, the dihedral angle between them being 4.69 (9)°. The asymmetric unit consists of half of the terephthalic acid (an inversion centre generates the other half of the molecule), one 4-(1H-pyrazol-3-yl)pyridine (4pp) molecule and one water molecule. In the crystal, two 4pp and one terephthalic acid molecules form a linear three-molecule unit as a result of O—H...N hydrogen bonds. These units are further assembled into a three-dimensional network by two types of hydrogen bonds, viz. O—H...O and N

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50

Xi, Li Min, and Xin Xin Zhang. "Direct Synthesis of 3,5-Dinitropyrazole Catalyzed by Newly Sulfated Nanosolid Superacid TiO₂/ SO." Advanced Materials Research 391-392 (December 2011): 1296–301. http://dx.doi.org/10.4028/www.scientific.net/amr.391-392.1296.

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The newly sulfated nanosolid superacid TiO2/SO4 prepared by sol-gel method was broadly characterized by acid base titration, XRD and TEM, which identified that the superfine solid TiO2/SO4 showing good dispersibility with average size of 27 nm belongs to kind of crystalline nanoparticles. With the help of the catalyst TiO2/SO4, the optimal reaction condition for direct transformation of pyrazole and nitrosonitric acid into 3, 5-Dinitropyrazole was n (pyrazol)=0.10 mol, m (TiO2/SO4 )＝1.5g, V(n-octannol)＝90mL, and V(nitrosonitric acid)＝50mL. Moreover, the optimal yield of the catalytic reaction

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