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Journal articles on the topic 'Pyrazolo[5'

Author: Grafiati

Published: 1 July 2022

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1

Abaszadeh, Mehdi, Hassan Sheibani, and Kazem Saidi. "The Condensation of (Chlorocarbonyl)phenyl Ketene with Bisnucleophiles. Synthesis of 4-Hydroxy-5-phenylpyro-[2,3-c]pyrazol-6-ones and Formation of Pyrazolo[1,2-a]pyrazole-triones by Hydrogen Exchange in Unstable Mesoionic Compounds." Australian Journal of Chemistry 63, no. 1 (2010): 92. http://dx.doi.org/10.1071/ch09344.

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The addition of (chlorocarbonyl)phenyl ketene 2 to 5-alkylpyrazol-3(4H)-ones 1 led to the formation of 3-hydroxypyrazolo[1,2-a]pyrazole-dione/pyrazolo[1,2-a]pyrazole-trione derivatives 3. This is ascribed to hydrogen exchange in initially formed unstable, mesoionic pyrazolo[1,2-a]pyrazol-4-ium-5-olates. In contrast, condensation of the same ketene with 3-alkyl-1-phenyl-2-pyrazolin-5-ones 4 afforded 4-hydroxy-3-alkyl-1,5-diphenylpyrano[2,3-c]pyrazol-6-one derivatives 5. The latter reaction provides a new and rapid route to 4-hydroxy-2-pyrones fused to pyrazole rings, in good to excellent yields.

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2

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 derivative XI. The reaction of I with pyridine 1-oxide affords 4H,5H-pyrazolo[5',1':2,3] [1,2,4]triazolo[1,5-a]pyridine-3-carbonitrile XII.

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3

Hosny, Mona A., Yasser H. Zaki, Wafaa A. Mokbel, and Abdou O. Abdelhamid. "Synthesis, Characterization, Antimicrobial Activity and Anticancer of Some New Pyrazolo[1,5-a]pyrimidines and Pyrazolo[5,1-c]1,2,4-triazines." Medicinal Chemistry 16, no. 6 (September 7, 2020): 750–60. http://dx.doi.org/10.2174/1573406415666190620144404.

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Background: Pyrazole and its derivatives are known to exhibit significant biological and pharmacological activities such as anticancer, anti-inflammatory, antioxidant, antibacterial, analgesic, antiviral, antimicrobial, antifungal, anti-glycemic, antiamoebic, and antidepressive. Considering the immense biological properties, pyrazole is one of the most widely studied nitrogen- containing heterocyclic nuclei. Fused pyrazole derivatives are composed of the pyrazole nucleus attached to other heterocyclic moieties. Objective: The objective of this article is the synthesis of some new pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c]1,2,4-triazine derivatives with potential anticancer and antimicrobial activities. Methods: The in vitro growth inhibitory rates (%) and inhibitory growth activity (as measured by IC50) of the newly synthesized compounds were determined against the MCF-7 human breast carcinoma cell line in comparison with the well-known anticancer drug doxorubicin as the standard, using the MTT viability assay. The data generated were used to plot a dose-response curve from which the concentration (μM) of tested compounds required to kill 50% of the cell population (IC50) was determined. Cytotoxic activity was expressed as the mean IC50 of three independent experiments. The difference between inhibitory activities of all compounds with different concentrations was statistically significant p < 0.001. All compounds were structurally characterized by different spectroscopic techniques EI-MS, 1H-NMR, and 13C-NMR, and evaluated for their anticancer and antimicrobial activities (antibacterial and antifungal). Results: Several pyrazolo[1,5-a]pyrimidine derivatives were synthesized from the reaction of 2-(4- (5-amino-1H-pyrazol-3-yl)phenyl)-1H-indene-1,3(2H)-dione with the appropriate active methylene compounds in boiling ethanol. Also, pyrazolo[5,1-c]triazines were obtained through the reaction of 2-(4-(5-(chlorodiazenyl)-1H-pyrazol-3-yl)phenyl)-1H-indene-1,3(2H)-dione with various active methylene compounds in ethanol containing sodium acetate at 0-5 °C. The structures of the newly synthesized compounds were elucidated on the basis of elemental analysis, spectral data, and alternative synthetic routes whenever possible. The newly synthesized compounds were evaluated for their antitumor activity against a breast cancer cell line (MCF-7) and a human colon cancer cell line (HCT-116). The results revealed that the tested compounds showed high variation in the inhibitory growth rates and activities against the tested tumor cell lines. All newly synthesized compounds screen towards microorganisms e.g. Gram-negative bacteria, Gram-positive bacteria, and Fungi. Conclusions: 2-(4-(5-Amino-1H-pyrazol-3-yl)phenyl)isoindoline-1,3-dione proved to be a useful precursor for the synthesis of various pyrazolo[1,5-a]pyrimidine and pyrazolo[5,1-c]-1,2,4- triazines. The structures of the newly synthesized compounds were confirmed by spectral data and elemental analyses. The newly synthesized compounds were tested in vitro against the MCF-7, HCT-116 human cancer cell line and compared with doxorubicin as the standard, using the MTT viability assay. Most of the tested compounds were found to have moderate to high anticancer activity.

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4

Elnagdi, Mohamed Hilmy, Ahmed Hafez Hussien Elghandour, Kamal Usef Sadek, and Mahmoud Mohamed Mahfouz Ramiz. "Studies on Condensed Pyrazoles. A New Route for Synthesis of Pyrazolo[4,3-c]pyrazoles." Zeitschrift für Naturforschung B 44, no. 8 (August 1, 1989): 951–54. http://dx.doi.org/10.1515/znb-1989-0816.

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A novel synthesis of pyrazolo[4,3-c]pyrazoles via 1,5-dipolar cyclization of products of coupling of 2,3-dimethyl-1-phenyl-5-oxo-3-pyrazolin-4-diazonium chloride with active methylene reagents is reported.

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5

Lindsay-Scott, Peter J., and Eloise Rivlin-Derrick. "Regiocontrolled Synthesis of 6,7-Dihydro-4H-pyrazolo[5,1-c][1,4]oxazines." Synthesis 52, no. 01 (October 8, 2019): 105–18. http://dx.doi.org/10.1055/s-0037-1610734.

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Synthetic access to 6,7-dihydro-4H-pyrazolo[5,1-c][1,4]oxazines has been achieved in 3–4 steps from commercially available pyrazoles. Optimization of a protected hydroxyethyl group on N1 enabled the regiocontrolled construction of pyrazole-5-aldehydes in high yields; subsequent deprotection and reduction generated fused heterocyclic scaffolds bearing multiple substitution patterns. Moreover, the intermediate pyrazole lactols were shown to be versatile synthetic building blocks.

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6

Abdelhamid, Abdou O., Zeineb H. Ismail, and Anhar Abdel-Aziem. "Reactions with Hydrazonoyl Halides 601: Synthesis of Thieno[2′,3′:4,5] Pyrimidino[1,2-b][1,2,4,5]tetrazines, [1]benzothieno[2′,3′:4,5]pyrimidino [1,2-b][1,2,4,5]tetrazines, Pyrazolo[3′,4′:4,5]pyrimidino[1,2-b] [1,2,4,5]tetrazines and Pyrazolo[3,4-d]pyridazines." Journal of Chemical Research 2007, no. 10 (October 2007): 609–16. http://dx.doi.org/10.3184/030823407x256118.

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Thieno[2′,3′:4,5]pyrimidino[1,2- b][1,2,4,5]tetrazine, [1]benzothieno-[2′,3′:4,5]pyrimidino[1,2- b][1,2,4,5]tetrazine, pyrazolo [3′,4′:4,5]pyrimidino[1,2- b][1,2,4,5]tetrazine, triazolo[4,3- a]pyrimidin-5(1 H)-one, 1-{[2-(1-benzofuran-2-yl)-5-phenyl-4,5-dihydro-1 H-pyrazol-1-yl]-4-substituted-1,3-thiazol-5-yl}-2-phenyldiazene, 3-acyl-4-(1-benzofuran-2-ylcarbonyl) pyrazole and pyrazolo[3,4- d]pyridazine derivatives could be obtained via reactions of hydrazonoyl halides with the appropriate pyrimidine-2-thione, 3-amino-5,6-dimethyl-2-sulfanylthieno[2,3- d]pyrimidin-4(3 H)-one, 5-amino-6-mercapto-1-phenyl-1,5-dihydropyrazolo[3,4- d]pyrimidin-4-one and 1-(benzofuran-2-yl)-3-(dimethylamino)prop-2-en-1-one. Structures of the products have been determined by elemental analyses, spectral data studies and alternative synthesis whenever possible.

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7

Forsyth, Craig M., Craig L. Francis, Saba Jahangiri, Andris J. Liepa, Michael V. Perkins, and Anna P. Young. "N,N-Dialkyl-N'-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part VIII. Novel Pyrazolo-Fused Oxathiadiazines and Thiatriazoles." Australian Journal of Chemistry 63, no. 4 (2010): 659. http://dx.doi.org/10.1071/ch09581.

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N,N-dialkyl-N′-chlorosulfonyl chloroformamidines 1 reacted with pyrazol-3-ones 2 under a variety of conditions to give pyrazolo[2,3-e][1,2,3,5]oxathiadiazine dioxides 3 and pyrazolo[3,2-b][1,4,3,5]oxathiadiazine dioxides 5, and frequently, one or both of pyrazolo[1,2-b][1,2,3,5]thiatriazole 1,1,5-trioxides 4 and 1,1,7-trioxides 6. In all reactions, the pyrazolo[3,2-b][1,4,3,5]oxathiadiazine 5 was the major product, with the pyrazolo[2,3-e][1,2,3,5]oxathiadiazine 3 being a significant product in the absence of base. Prior to our recent work, the core ring systems of compounds 3 and 5 had not been reported and compounds 4 and 6 are new derivatives of a rare ring system.

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8

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]triazines 5. Attempted catalytic hydrogenolysis of N7-benzyl pyrazolo[1,5-b][1,2,4,6]thiatriazines 2 in alcohols led to sulfamates 12 from thiatriazine ring cleavage. Ethyl acetate or tert-butanol as solvent allowed successful debenzylation to provide compounds 1. Aminolysis of compounds 2 gave sulfamides 13. Thermal rearrangement of compounds 2 afforded 6-benzyl-pyrazolo[3,4-e][1,2,4]thiadiazines 14.

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9

Mokhonova, Inna D., Evgenij A. Maksimov, Irina V. Ledenyona, Alevtina Y. Yegorova, and Khidmet S. Shikhaliev. "Reactions of 3H-furan-2-ones and 2H-chromen-2-ones with pyrazole-3(5)-diazonium salts." Heterocyclic Communications 24, no. 4 (August 28, 2018): 183–85. http://dx.doi.org/10.1515/hc-2017-0192.

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AbstractDerivatives of the new heterocyclic system, 6H-chromeno[4,3-e]pyrazolo[5,1-c][1,2,4]triazin-6-one, were obtained by the reaction of pyrazole-3(5)-diazonium salts with 4-hydroxy-2H-chromen-2-one. Similar reactions with 5-phenyl-3H-furan-2-one followed by intramolecular heterocyclization furnished 6-(4-halophenyl)-7-alkyl-2-phenylfuro[2,3-e]pyrazolo[5,1-c][1,2,4]triazines.

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10

Abdelhamid, Abdou O., Victorin B. Baghos, and Mervat M. A. Halim. "Synthesis and reactivity of N-[3-amino-4-(benzoxazol-2-yl)pyrazol-5-yl]phenylamine." Journal of Chemical Research 2007, no. 7 (July 2007): 420–25. http://dx.doi.org/10.3184/030823407x228830.

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Pyrazolo[5,1- a]pyrimidines and pyrazolo[5,1-c][1,2,4]triazines containing benzooxazole moiety are synthesised from N-[3-amino-4-(benzoxazol-2-yl)pyrazol-5-yl]phenylamine or its diazonium chloride with the appropriate active methylene compounds. The newly synthesised compounds were elucidated by elemental analysis, spectral data and alternative synthetic route whenever possible.

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11

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 is given to the novel structures especially in regard to the promising pharmaceutical and therapeutic values associated with their skeletons.

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12

Hu, Hua-nan, You Peng, Hua-nan Huang, Tao Yang, Fu-shan Chen, and Ping Yan. "Deacylation during the Synthesis of New 4-Amino-1H-Pyrazolo [3,4-B] Pyridines Catalysed by Sncl4." Journal of Chemical Research 42, no. 8 (August 2018): 412–15. http://dx.doi.org/10.3184/174751918x15337230783041.

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A series of novel 1-(4-amino-6-methyl-1-aryl-1H-pyrazolo[3,4-b]pyridin-5-yl)-ethanones and 6-methyl-1-aryl-1H-pyrazolo[3,4-b]pyridin-4-amines were prepared by the annulation of 5-amino-1-aryl-1H-pyrazole-4-carbonitriles with acetylacetone in the presence of tin(IV) chloride. The results demonstrated that the ethanones are the precursors of second compounds.

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13

Dodiya, Dipti, Amit Trivedi, Samir Jarsania, Shailesh Vaghasia, and Viresh Shah. "Characterization and biological evaluation of some novel pyrazolo[3',4':4,5]thieno[2,3-d]pyrimidin-8-ones synthesized via the Gewald reaction." Journal of the Serbian Chemical Society 73, no. 7 (2008): 683–90. http://dx.doi.org/10.2298/jsc0807683d.

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The synthesis of substituted pyrazolo[3',4':4,5]thieno[2,3-d]pyrimidin-8-ones (IIIa-j) from 5-amino-3-methyl-1H-thieno[3,2-c]pyrazole-6-carbonitrile (II) is described. The key compound II was synthesized from (5-methyl- -2,4-dihydro-3H-pyrazol-3-ylidene)malononitrile I via the Gewald reaction. The synthesis of the title compounds IIIa-j was accomplished by condensation of II with different aromatic aldehydes. The newly synthesized heterocyles were characterized by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectroscopic investigation. All the newly synthesized compounds were evaluated for antimicrobial activity against a variety of bacterial strains. .

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14

Rizk, Sameh, Ismail M. Awheda, and Fathi A. Smida. "Synthesis and DFT Study of Newly Schiff Base and Fused Heterocyclic Compounds as Antibacterial Agent." JOURNAL OF ADVANCES IN CHEMISTRY 16 (November 7, 2019): 5395–403. http://dx.doi.org/10.24297/jac.v16i0.8499.

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Treatment of 2,3-di-(4-chlorophenyl) oxirane-2,3-dicarbonitriles(1) with nitrogen nucleophiles, e.g. N2H4, NH2OH afforded pyrazole 2, 1.2oxazole 3 derivatives respectively The 3-amino pyrazole-4-one derivatives 2 can be used as a key starting materials to synthesize some important Schiff base 4 and fused heterocyclic compounds e.g. Imidazolo-[4,5-c]pyrazole 5, Pyrazolo[3,4-e]1,2,4-triazine 6, pyrazol[1,2-a] 1,3,5-triazine 7, 8 and 9. The electromeric effect of the halogen atom in the aryl moieties can be controlled upon the rate of reaction and the yield of the product. The structures of synthesized new compounds were characterized by spectral data and screened for their antimicrobial activities against various bacteria and fungi strains. The heterocyclic compounds 7, 8 and 9 that contained bridgehead nitrogen gave an excellent result.

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15

Ogurtsov, Vladimir, and Oleg Rakitin. "4-Chloro-6-(chloromethyl)-1-methyl-1H-pyrazolo[3,4-d]pyrimidine." Molbank 2021, no. 3 (July 22, 2021): M1253. http://dx.doi.org/10.3390/m1253.

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A novel 4-chloro-6-(chloromethyl)-1-methyl-1H-pyrazolo[3,4-d]pyrimidine was prepared by a rational and short two-step synthesis from commercially available ethyl 5-amino-1-methyl-1H-pyrazole-4-carboxylate via 6-(chloromethyl)-1-methyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one. The structure of the synthesized compounds was established by elemental analysis, high-resolution mass-spectrometry, 1H, 13C-NMR and IR spectroscopy and mass-spectrometry. 4-Chloro-6-(chloromethyl)-1-methyl-1H-pyrazolo[3,4-d]pyrimidine is a convenient intermediate for various disubstituted 1-methyl-1H-pyrazolo[3,4-d]pyrimidines, which may be of interest as substances with useful pharmacological properties.

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16

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 (November 1, 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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17

Halim, Shimaa Abdel, and Magdy A. Ibrahim. "Synthesis, spectral analysis, quantum studies, NLO, and thermodynamic properties of the novel 5-(6-hydroxy-4-methoxy-1-benzofuran-5-ylcarbonyl)-6-amino-3-methyl-1H-pyrazolo[3,4-b] pyridine (HMBPP)." RSC Advances 12, no. 21 (2022): 13135–53. http://dx.doi.org/10.1039/d2ra01469f.

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Ring opening followed by ring closure reactions of 4-methoxy-5-oxo-5H-furo[3,2-g] chromene-6-carbonitrile with 5-amino-3-methyl-1H-pyrazole gave the novel 5-(6-hydroxy-4-methoxy-1-benzofuran-5-ylcarbonyl)-6-amino-3-methyl-1H-pyrazolo[3,4-b] pyridine.

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18

Dorn, Helmut, and Alfred Zubek. "Pyrazolo [1, 5-a]pyrimidine aus 3 (5)-Amino-pyrazol und Acetessigester." Zeitschrift für Chemie 7, no. 9 (September 2, 2010): 343. http://dx.doi.org/10.1002/zfch.19670070908.

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19

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 (August 1, 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 (11) from the condensation products 1 and 2, derived from 1,3-diaryl-2-thiobarbituric acids is described.Key words: synthesis, fused, pyrazole, isoxazole, pyrimidines.

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20

Palka, Barbara, Angela Di Capua, Maurizio Anzini, Gyté Vilkauskaité, Algirdas Šačkus, and Wolfgang Holzer. "Synthesis of trifluoromethyl-substituted pyrazolo[4,3-c]pyridines – sequential versus multicomponent reaction approach." Beilstein Journal of Organic Chemistry 10 (July 31, 2014): 1759–64. http://dx.doi.org/10.3762/bjoc.10.183.

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A straightforward synthesis of 6-substituted 1-phenyl-3-trifluoromethyl-1H-pyrazolo[4,3-c]pyridines and the corresponding 5-oxides is presented. Hence, microwave-assisted treatment of 5-chloro-1-phenyl-3-trifluoromethylpyrazole-4-carbaldehyde with various terminal alkynes in the presence of tert-butylamine under Sonogashira-type cross-coupling conditions affords the former title compounds in a one-pot multicomponent procedure. Oximes derived from (intermediate) 5-alkynyl-1-phenyl-3-trifluoromethyl-1H-pyrazole-4-carbaldehydes were transformed into the corresponding 1H-pyrazolo[4,3-c]pyridine 5-oxides by silver triflate-catalyzed cyclization. Detailed NMR spectroscopic investigations (1H, 13C, 15N and 19F) were undertaken with all obtained products.

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21

Norman, Rebecca E., Michael V. Perkins, Andris J. Liepa, and Craig L. Francis. "N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XI. Some Substitution Reactions of Pyrazolo[1,5-b][1,2,4,6]thiatriazine 1,1-Dioxides." Australian Journal of Chemistry 68, no. 7 (2015): 1011. http://dx.doi.org/10.1071/ch14547.

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The recently discovered pyrazolo[1,5-b][1,2,4,6]thiatriazine template was shown to possess four nucleophilic sites (N2, N4, C5, N7) that underwent a range of substitution reactions. Methylation occurred at both N4 and N7. Alkylation with benzylic halides occurred preferentially at N7, regardless of the solvent, but also occurred at C5, N4, and N2. Similar alkylation with α-halo esters occurred at both N4 and N7, but the latter derivatives underwent a novel pyrazole ring expansion to afford pyrimido[1,6-b][1,2,4,6]thiatriazine derivatives. Bromination of pyrazolo[1,5-b][1,2,4,6]thiatriazines afforded unstable 5-bromo derivatives. Tosylation occurred selectively at C5, but in modest yield; catalysis with 1-methylimidazole also led to a low yield of the 5,5′-dimer. The action of HCl on N7-benzylated pyrazolo[1,5-b][1,2,4,6]thiatriazines readily caused extrusion of sulfur dioxide to produce pyrazolo-guanidines.

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22

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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23

Secrieru, Alina, Paul Michael O’Neill, and Maria Lurdes Santos Cristiano. "Revisiting the Structure and Chemistry of 3(5)-Substituted Pyrazoles." Molecules 25, no. 1 (December 20, 2019): 42. http://dx.doi.org/10.3390/molecules25010042.

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Pyrazoles are known as versatile scaffolds in organic synthesis and medicinal chemistry, often used as starting materials for the preparation of more complex heterocyclic systems with relevance in the pharmaceutical field. Pyrazoles are also interesting compounds from a structural viewpoint, mainly because they exhibit tautomerism. This phenomenon may influence their reactivity, with possible impact on the synthetic strategies where pyrazoles take part, as well as on the biological activities of targets bearing a pyrazole moiety, since a change in structure translates into changes in properties. Investigations of the structure of pyrazoles that unravel the tautomeric and conformational preferences are therefore of upmost relevance. 3(5)-Aminopyrazoles are largely explored as precursors in the synthesis of condensed heterocyclic systems, namely pyrazolo[1,5-a]pyrimidines. However, the information available in the literature concerning the structure and chemistry of 3(5)-aminopyrazoles is scarce and disperse. We provide a revision of data on the present subject, based on investigations using theoretical and experimental methods, together with the applications of the compounds in synthesis. It is expected that the combined information will contribute to a deeper understanding of structure/reactivity relationships in this class of heterocycles, with a positive impact in the design of synthetic methods, where they take part.

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24

Ning, Yi, Xinwei He, Youpeng Zuo, Jian Wang, Qiang Tang, Mengqing Xie, Ruxue Li, and Yongjia Shang. "Rh-Catalyzed C–H activation/intramolecular condensation for the construction of benzo[f]pyrazolo[1,5-a][1,3]diazepines." Organic & Biomolecular Chemistry 18, no. 15 (2020): 2893–901. http://dx.doi.org/10.1039/d0ob00382d.

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A novel and mild Rh(iii)-catalyzed cascade C–H activation/intramolecular condensation of 1-aryl-1H-pyrazol-5-amines with cyclic 2-diazo-1,3-diketones for the synthesis of various important benzo[f]pyrazolo[1,5-a][1,3]diazepines has been developed.

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25

Wiethan, Carson, Steffany Z. Franceschini, Helio G. Bonacorso, and Mark Stradiotto. "Synthesis of pyrazolo[1,5-a]quinoxalin-4(5H)-ones via one-pot amidation/N-arylation reactions under transition metal-free conditions." Organic & Biomolecular Chemistry 14, no. 37 (2016): 8721–27. http://dx.doi.org/10.1039/c6ob01407k.

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An efficient one-pot procedure for the synthesis of new pyrazolo[1,5-a]quinoxalin-4(5H)-ones from easily prepared 1-(2-chlorophenyl-5-ethylcarboxylate)pyrazoles and various primary alkylamines is described.

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26

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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27

Polo, Efraín, Valentina Arce-Parada, Xaviera A. López-Cortés, Jesús Sánchez-Márquez, Alejandro Morales-Bayuelo, Oscar Forero-Doria, and Margarita Gutiérrez. "Synthesis of Pyrazolo-Fused 4-Azafluorenones in an Ionic Liquid. Mechanistic Insights by Joint Studies Using DFT Analysis and Mass Spectrometry." Catalysts 9, no. 10 (September 29, 2019): 820. http://dx.doi.org/10.3390/catal9100820.

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A series of pyrazolo-fused 4-azafluorenones (indeno[1,2-b]pyrazolo[4,3-e]pyridines, IPP) were synthesized via the three-component reaction between arylaldehydes, 3-methyl-1H-pyrazol-5-amine and 1,3-indanedione in an ionic liquid as a catalyst at room temperature. The applied synthetic route has the advantages of easy work-up under mild reaction conditions presenting moderate yields and an environmentally benign procedure. A theoretical study based on conceptual-density functional theory has been done, bond reactivity indices have been calculated and an electrophilic and nucleophilic character of localized orbitals has been determined to analyze the possible electronic mechanisms.

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28

Barton, Richard J., Keith E. Johnson, Beverly E. Robertson, F. Wayne Yerhoff, and Shengzhi Hu. "Structures of the pyrazolones formed by oxidative coupling of phenols with 4-aminoantipyrine." Canadian Journal of Chemistry 65, no. 9 (September 1, 1987): 2082–88. http://dx.doi.org/10.1139/v87-345.

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The structures of reaction products between 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one and o-cresol, p-cresol, and p-ethylphenol are reported. The reaction of the former compound with phenols is used to estimate the concentration of phenol in potable water supplies. The reaction products are 2,3-dimethyl-4-[4-oxo-2,5-cyclohexadien-1-ylidene)amino]-1-phenyl-3-pyrazolin-5-one (monoclinic, P21/c, red, Z = 4, a = 7.092(1), b = 26.616(2), c = 8.644(2) Å, β = 79.17(3)°, 1432 reflections, R = 0.083, Rw = 0.040), 1,9a-dihydro-1,6,9a-trimethyl-2-phenylpyrazolo[3,4-b][1,4]benzoxazin-3(2H)-one (orthorhombic, Pbca, yellow, Z = 8, a = 18.943(3), b = 12.749(5), c = 13.223(2) Å, 2122 reflections, R = 0.067, Rw = 0.038), and 6-ethyl-1,9a-dihydro-1,9a-dimethyl-2-phenylpyrazolo[3,4-b|[1,4]benzoxazin-3(2H)-one (orthorhombic, Pbca, yellow, a = 18.895(11), b = 12.737(5), c = 14.041(6) Å, Z = 8, 1126 reflections, R = 0.068, Rw = 0.061), respectively. The latter two compounds rearrange to form 1,2,4,10-tetrahydro-1,6-dimethyl-2-phenyl-3H-pyrazolo[3,4-c][1,5]benzoxazepin-3-one (monoclinic, P21/c, white, Z = 8, a = 15.072(4), b = 14.491(4), c = 15.505(3) Å, β = 111.15(1)°, 3416 reflections, R = 0.101, Rw = 0.046) and 6-ethyl-1,2,4,10-tetrahydro-1-methyl-2-phenyl-3H-pyrazolo[3,4-c][1,5]benzoxazepin-3-one (monoclinic, C2/c, white, Z = 8, a = 33.768(3), b = 6.678(1), c = 15.836(2) Å, β = 115.41(1), 2805 reflections, R = 0.076, Rw = 0.043), respectively. The rearrangement is consistent with the observation that the pyrazolone rings of benzoxazinones are strained, as manifested by enlarged perimeters.

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29

Surya Prakash Rao, H., Ramalingam Gunasundari, and Jayaraman Muthukumaran. "Crystal structure analysis of ethyl 6-(4-methoxyphenyl)-1-methyl-4-methylsulfanyl-3-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate." Acta Crystallographica Section E Crystallographic Communications 76, no. 8 (July 7, 2020): 1209–12. http://dx.doi.org/10.1107/s2056989020008841.

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In the title compound, C24H23N3O3S, the dihedral angle between the fused pyrazole and pyridine rings is 1.76 (7)°. The benzene and methoxy phenyl rings make dihedral angles of 44.8 (5) and 63.86 (5)°, respectively, with the pyrazolo[3,4-b] pyridine moiety. An intramolecular short S...O contact [3.215 (2) Å] is observed. The crystal packing features C—H...π interactions.

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30

Mague, Joel T., Shaaban K. Mohamed, Mehmet Akkurt, Talaat I. El-Emary, and Mustafa R. Albayati. "Crystal structure of 5-(4,5-dihydro-1H-imidazol-2-yl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyrazin-6-amine." Acta Crystallographica Section E Structure Reports Online 70, no. 11 (October 31, 2014): o1212—o1213. http://dx.doi.org/10.1107/s160053681402354x.

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In the title compound, C15H15N7, the phenyl ring is inclined by 19.86 (5)° to the mean plane of the pyrazolo[3,4-b]pyrazine core. In the crystal, N—H...N and C—H...N hydrogen bonds form [010] chains, which stackviaπ–π interactions [centroid–centroid distance between the pyrazole rings = 3.4322 (7) Å].

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31

Poursattar Marjani, Ahmad, Jabbar Khalafy, Fatemeh Salami, and Mahsa Mohammadlou. "Tin(II) Chloride Catalyzed Synthesis of New Pyrazolo[5,4-b]quinolines under Solvent-Free Conditions." Synthesis 47, no. 11 (March 12, 2015): 1656–60. http://dx.doi.org/10.1055/s-0034-1380189.

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A series of new pyrazolo[5,4-b]quinoline derivatives were synthesized in good yields by tin(II) chloride dihydrate catalyzed cyclocondensation of 5-amino-3-(arylamino)-1H-pyrazole-4-carbonitriles with cyclohexane-1,3-dione or dimedone. The synthetic procedure can be carried out by means of simple operations under convenient solvent-free conditions.

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32

Forsyth, Craig M., Craig L. Francis, Saba Jahangiri, Andris J. Liepa, Michael V. Perkins, and Anna P. Young. "N,N-Dialkyl-N'-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part IX. Novel Triazolo-Fused Thiatriazoles and Pyrazolo-Fused Oxathiazines." Australian Journal of Chemistry 63, no. 5 (2010): 785. http://dx.doi.org/10.1071/ch09607.

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N,N-dialkyl-N′-chlorosulfonyl chloroformamidines 1 reacted with 4-substituted urazoles 2 to give [1,2,4]triazolo[1,2-b][1,2,3,5]thiatriazoles 3 in a selective 1,2-NN dinucleophilic mode of reaction. The reaction of 1 with N 1-substituted pyrazol-5-ones 4 afforded pyrazolo[4,3-e][1,4,3]oxathiazines 5 via selective 1,3-CCO dinucleophilic substitution. Compounds 3 and 5 were the sole products isolated from the respective reactions and both represent new ring systems.

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33

Ezzati, Mahnaz, Jabbar Khalafy, Ahmad Poursattar Marjani, and Rolf H. Prager. "An Efficient One-Pot, Four-Component Synthesis of Pyrazolo[3,4-b]pyridines Catalyzed by Tetrapropylammonium Bromide (TPAB) in Water." Australian Journal of Chemistry 71, no. 6 (2018): 435. http://dx.doi.org/10.1071/ch17642.

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A novel and one-pot pseudo-four-component reaction between a series of arylglyoxals, malononitrile, 3-methyl-1-phenyl-1H-pyrazol-5-amine, and acetone in the presence of tetrapropylammonium bromide (TPAB) has been developed to synthesize a series of new substituted pyrazolo[3,4-b]pyridines, using water as an environmentally friendly solvent, in high to excellent yields.

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34

Gharib, Ali, Bibi Robabeh Hashemipour Khorasani, Manouchehr Jahangir, Mina Roshani, and Reza Safaee. "Catalytic Synthesis of 3-Methyl-1-phenyl-1H-benzo[g]pyrazolo[3,4-b]quinoline-5,10-dione Derivatives Using Cerium Oxide Nanoparticles as Heterogeneous Catalyst in Green Conditions." Organic Chemistry International 2013 (August 6, 2013): 1–5. http://dx.doi.org/10.1155/2013/584708.

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We have developed a new methodology for the synthesis of 3-methyl-1-phenyl-1H-benzo[g]pyrazolo[3,4-b]quinoline-5,10-dione derivatives in excellent yields. A new green chemistry protocol with the reusability of the nanoparticle as catalyst has been developed for the synthesis of 3-methyl-1-phenyl-1H-benzo[g]pyrazolo[3,4-b]quinoline-5,10-dione derivatives via one-pot reaction of 3-methyl-1-phenyl-1H-pyrazol-5-amine, arylaldehydes, and 2-hydroxynaphthalene-1,4-dione in water as green solvent and using cerium oxide nanoparticles (CONPs) as heterogeneous catalyst. The present methodology affords several advantages such as simple procedure, excellent yields, and short reaction time. The catalyst is inexpensive, stable, easily recycled, and reused for several cycles with consistent activity.

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35

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]isoindole (11, 12.5% yield) and trans-3-(4-methylphenyl)-3a,8-dihydro-3H-pyrazolo[5,1-a]isoindole (12, 5% yield). Thermal reactions afforded 3-(4-methylphenyl)-3,3a,8,8a-tetrahydroindeno[2,1-c]pyrazole (14, 50% yield) and 11-(4-methylphenyl)-9,10-diazatricyclo[7.2.1.02,7]dodeca-2,4,6,10-tetraene (15, 22% yield).

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36

Hennig, L., T. Müller, and M. Grosche. "Synthese von Pyrazolo[3,4-b]chinolinen aus 4-Aroyl-5-chlor-pyrazolen." Journal für Praktische Chemie 332, no. 5 (1990): 693–98. http://dx.doi.org/10.1002/prac.19903320518.

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37

Abd El Latif, Fawi M., Magda A. Barsy, Eman A. Elrady, and M. Hassan. "New Routes for Novel Pyrazolo[3,4-b][1,6]-naphthyridine, Pyrazolo[3,4-b]pyridine and Pyrazolo[3,4:2,3]pyrido[6,1-a]benzimidazole Derivatives." Journal of Chemical Research 23, no. 12 (December 1999): 696–97. http://dx.doi.org/10.1177/174751989902301206.

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Pyrazolo[3,4- b] [1,6] naphthyridine, pyrazolo[3,4- b] pyridine and pyrazolo[3,4:2,3] pyrido [6,1 -a] benzimidazole derivatives are synthesized starting from the isomeric 3-substituted 5-chloro-1-phenylpyrazole-4-carbaldehyde.

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38

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 (February 9, 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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39

Noh, Eun Sun, Sung Min Kim, and Yang-Heon Song. "4-(3-Phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)thieno[3,2-d]pyrimidine." Molbank 2020, no. 2 (May 17, 2020): M1136. http://dx.doi.org/10.3390/m1136.

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A new hybrid compound, 4-(3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-1-yl)thieno[3,2-d]pyrimidine 3, with promising biological activity was efficiently synthesized by the reaction of 3-phenyl-1-(thieno[3,2-d]pyrimidin-4-yl)-1H-pyrazol-5-amine with Vilsmeier–Haack reagent and subsequent treatment with ammonium carbonate. The structure of the synthesized compound was fully characterized by 1H-, 13C-NMR, IR spectroscopy, mass-spectrometry and elemental analysis.

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40

Alsayari, Abdulrhman, Abdullatif Bin Muhsinah, Yahya I. Asiri, Jaber Abdullah Alshehri, Yahia N. Mabkhot, Mohammad Y. Alfaifi, Serag Eldin I. Elbehairi, Mater H. Mahnashi, and Mohd Zaheen Hassan. "Arylhydrazono/Aryldiazenyl Pyrazoles: Green One-Pot Solvent-Free Synthesis and Anticancer Evaluation." Letters in Organic Chemistry 17, no. 10 (November 17, 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, some hybrid analogues containing the bioactive pharmacophores viz. pyrazole, pyridine, and diazo scaffolds were synthesized by one-pot method. Herein, we describe the expedient synthesis of pyrazoles by a onepot three-component condensation of ethyl acetoacetate/acetylacetone, isoniazid, and arenediazonium salts under solvent-free conditions, and the evaluation of their cytotoxicity using a sulforhodamine B assay on three cancer cell lines. Molecular docking studies employing tyrosine kinase were also carried out to evaluate the binding mode of the pyrazole derivatives under study. 1-(4-Pyridinylcarbonyl)-3- methyl-4-(2-arylhydrazono)-2-pyrazolin-5-ones and [4-(2-aryldiazenyl)-3,5-dimethyl-1H-pyrazol-1- yl]-4-pyridinylmethanones, previously described, were prepared using an improved procedure. Among these ten products, 1-isonicotinoyl-3-methyl-4-[2-(4-nitrophenyl)hydrazono]-2-pyrazolin-5-one (1f) displayed promising anticancer activity against the MCF-7, HepG2 and HCT-116 cell lines, with an IC50 value in the range of 0.2-3.4 μM. In summary, our findings suggest that pyrazoles containing hydrazono/ diazenyl and pyridine pharmacophores constitute promising scaffolds for the development of new anticancer agents.

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41

Moustafa, Moustafa Sherif, Ahmed Moukhtar Nour-Eldeen, Saleh Mohamed Al-Mousawi, Afaf Abd El-Hameed, Michael Magdy, and Kamal Usef Sadek. "Regioselectivity in the reaction of 5-amino-3-anilino-1H-pyrazole-4-carbonitrile with cinnamonitriles and enaminones: Synthesis of functionally substituted pyrazolo[1,5-a]pyrimidine derivatives." Green Processing and Synthesis 11, no. 1 (January 1, 2022): 116–28. http://dx.doi.org/10.1515/gps-2022-0009.

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Abstract The development of efficient methods for the synthesis of polyfunctional N-heterocycles is an important area of research in organic and medicinal chemistry. Pyrazolo[1,5-a]pyrimidine derivatives are purine analogous of biomedical importance and have been extremely studied for their broad spectrum of biological activities. Recently, they have attracted great interest in materials science owing to their photophysical properties. 3(5)-Aminopyrazoles are extensively utilized in the synthesis of condensed heterocyclic systems, particularly pyrazolo[1,5-a]pyrimidines via the reaction with 1,3-biselectrophilic reagents. However, the information available in the literature provides little in the way of reasoning their cyclization, particularly the initial attack either by the exocyclic amino group or endocyclic nitrogen. Unfortunately, the relative nucleophilicity of exo- and endocyclic nitrogen atoms in 1-unsubstituted 3(5)-aminopyrazoles is not clear and contradicting. It has been found that other factors can modulate the regioselectivity rather than basicity or steric hindrance for both active sites. The reported studies in the structure–activity relationship revealed that pyrazolo[1,5-a]pyrimidines having a substitution at fifth, sixth, and seventh positions possess potent biological activities, especially those with an amino group at the seventh position. We here developed a regioselective, high yield synthesis of 7-amino-5-arylpyrazolo[1,5-a]pyrimidine-3,6-dicarbonitriles by the reaction of N-(5-amino-4-cyano-1H-pyrazole-3-yl)-benzamide with various cinnamonitriles and enaminones in pyridine at 120°C under controlled microwave heating conditions. All structures of newly synthesized compounds were established by analytical and spectral data as well as single-crystal diffraction and rationalized for their formation.

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42

El-Kashef, Hussein, Talaat El-Emary, Pierre Verhaeghe, Patrice Vanelle, and Maha Samy. "Anticancer and Anti-Inflammatory Activities of Some New Pyrazolo[3,4-b]pyrazines." Molecules 23, no. 10 (October 16, 2018): 2657. http://dx.doi.org/10.3390/molecules23102657.

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New derivatives of pyrazolo[3,4-b]pyrazines and related heterocycles were synthesized using 5-amino-3-methyl-4-nitroso-1-phenyl-pyrazole (1) as a starting material. The 5-acetyl derivative 15 was shown to be a useful key intermediate for the synthesis of several derivatives of pyrazolopyrazines. Some of the prepared compounds were evaluated for their anti-inflammatory and anti-breast cancer MCF-7 cell line activities. SAR study showed that compounds 15 and 29 exhibited remarkable anti-inflammatory activity, where 15 showed the same activity as that of the reference drug indomethacin. On the other hand, compounds 25i, 25j showed very significant inhibitory activity (p < 0.001) against MCF-7 breast cancer cell line.

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43

Ho, Yuh-Wen, and Maw Cherng Suen. "Thioxopyrimidine in Heterocyclic Synthesis I: Synthesis of Some Novel 6-(Heteroatom-substituted)-(thio)pyrimidine Derivatives." Journal of Chemistry 2013 (2013): 1–15. http://dx.doi.org/10.1155/2013/765243.

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A series of novel N-cycloalkanes, morpholine, piperazines, pyrazole, pyrimidine, benzimidazolo[1,2-a]pyrimidine, 1,2,3,4-tetrazolo[1,5-a]pyrimidine, azopyrazolo[1,5- a]pyrimidine, pyrimido[4', 5':3,4]pyrazolo[1,5-a]pyrimidines and pyridine derivatives incorporating a 5-cyano-4-methyl-2-phenyl-(thio)pyrimidine moiety were obtained by the intramolecular cyclization of 6-methylthio-pyrimidine, 6-(benzoylmethyl)thio- pyrimidine and 2-[(5-cyano-4-methyl-2-phenylpyrimidin-6-yl)thio]-3-dimethyl- amino-1-phenyl-prop-2-en-1-one with appropriate amines and enaminone compounds, respectively. The structure of all new synthesized compounds was established from their spectral data, elemental analysis and the X-ray crystal analysis.

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44

Ibrahim, Yusria R. "Synthesis of spiro(cyclohexa-diene-pyrazolo[1,5-a]pyrimidine-4-ylidene)-malononitrile derivatives." Journal of Chemical Research 2009, no. 8 (August 2009): 495–98. http://dx.doi.org/10.3184/030823409x466717.

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The reaction of 4-substituted aryldiazenyl-1 H-pyrazole-3,5-diamines with 7,7′,8,8′-tetra-cyanoquinodimethane gave 2-(2′,7′-diamino-6′-cyano-3′-(aryldiazenyl)-4′ H-spiro(cyclohexa[2,5]-diene-1,5′-pyrazolo[1,5- a]pyrimidine-4-ylidene) malononitriles in 63–79% yield, while, by reaction of 2-aminobenzimidazole with 7,7′,8,8′-tetracyanoquinodimethane, 2-(3′-amino-4′-cyano-6′ H-spiro-(cyclohexa[2′,5′]diene-1,5′-benzo( d)-imidazo[1,2- a]pyrimidine)-4-ylidene)malononitrile was formed in 71% yield. Rationales for these transformations are presented.

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45

Abdelhamid, Abdou O., Hamdi M. Hassaneen, and Ahmad S. Shawali. "Synthesis of pyrazolo[3,2-c]-1,2,4-triazines fromN-(5-pyrazolyl)-α-ketohydrazidoyl halides." Journal of Heterocyclic Chemistry 22, no. 2 (March 1985): 453–55. http://dx.doi.org/10.1002/jhet.5570220249.

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46

Voronin, V. G., Z. I. Shramova, S. Ya Skachilova, L. D. Kulikova, A. I. Ermakov, A. S. Zaks, and M. L. Suslina. "Biological activity of 4-methyl-5-phenyl-6-oxo-[4H]-pyrazolo[3,4-d]pyrazole." Pharmaceutical Chemistry Journal 19, no. 10 (October 1985): 700–705. http://dx.doi.org/10.1007/bf00767173.

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47

Gad-Elkareem, Mohamed A. M., Azza M. Abdel-Fattah, and Mohamed A. A. Elneairy. "Pyrazolo[3,4-b]pyridine in heterocyclic synthesis: synthesis of new pyrazolo[3,4-b]pyridines, imidazo[1',2':1,5]pyrazolo[3,4-b]pyridines, and pyrido[2',3':3,4]pyrazolo[1,5-a]pyrimidines." Canadian Journal of Chemistry 85, no. 9 (September 1, 2007): 592–99. http://dx.doi.org/10.1139/v07-089.

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Pyrazolo[3,4-b]pyridine derivatives 7 and 9 were synthesized via the reaction of 3-amino-1H-pyrazolo-[3,4-b]pyridine derivative 2 with ω-bromoacetophenones. Reaction of 7 and 9 with Ac2O afforded the imidazo[1',2':1,5]py razolo[3,4-b]pyridine derivative 8 and pyrazolo[3,4-b]pyridine derivative 10, respectively. Reaction of 2 with chloroacetonitrile followed by DMF-DMA gave imidazo[1',2':1,5]pyrazolo[3,4-b]pyridines 4 and 5, respectively. Acetyl acetone and 1,1-dicyano-2,2-dimethylthioethene were reacted with 2 to afford the pyrido[2',3':3,4]pyrazolo-[1,5-a]-pyrimidines 11 and 14, respectively. Also, 2 reacted with DMF-DMA to yield the formamidine 15, which in turn, reacted with active methylene reagents, yielding the corresponding pyrido[2',3':3,4]pyrazolo[1,5-a]pyrimidines 18 and 23a-23d.Key words: 1H-pyrazolo[3,4-b]pyridines, imidazo[1',2':1,5]pyrazolo[3,4-b]pyridines, pyrido[2',3':3,4]pyrazolo[1,5-a]pyrimidines.

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48

Jin Liu, Jin Liu, Juan Zhao Juan Zhao, and Jiu fu Lu Jiu fu Lu. "Synthesis, Crystal Structure and Antitumor Activity of 3-(2,4-dichlorophenyl)-2-phenyl-5-(p-tolyl)-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine." Journal of the chemical society of pakistan 42, no. 4 (2020): 591. http://dx.doi.org/10.52568/000663.

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Abstract:

The title compound, 3-(2,4-dichlorophenyl)-2-phenyl-5-(p-tolyl)- 7-(trifluoromethyl)pyrazolo[1,5-a] pyrimidine (C26H16Cl2F3N3, Mr = 498.32) has been synthesized by condensation of 4,4,4-trifluoro-1-(p-tolyl)butane- 1,3-dione with 4-(2,4-dichlorophenyl)-3-phenyl-1H-pyrazol-5-amine. The latter was prepared from 2,4-dichlorophenylaceton itrile and ethyl benzoate through Claisen condensation and then cyclization with hydrazine hydrate. The crystal structure of the title compound was determined. In addition, the title compound possesses marked inhibition against the proliferation of human lung adenocarcinoma cell line A549 and human gastric cancer cell line MKN45, displaying promising anticancer activities.

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49

Jin Liu, Jin Liu, Juan Zhao Juan Zhao, and Jiu fu Lu Jiu fu Lu. "Synthesis, Crystal Structure and Antitumor Activity of 3-(2,4-dichlorophenyl)-2-phenyl-5-(p-tolyl)-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidine." Journal of the chemical society of pakistan 42, no. 4 (2020): 591. http://dx.doi.org/10.52568/000663/jcsp/42.04.2020.

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Abstract:

The title compound, 3-(2,4-dichlorophenyl)-2-phenyl-5-(p-tolyl)- 7-(trifluoromethyl)pyrazolo[1,5-a] pyrimidine (C26H16Cl2F3N3, Mr = 498.32) has been synthesized by condensation of 4,4,4-trifluoro-1-(p-tolyl)butane- 1,3-dione with 4-(2,4-dichlorophenyl)-3-phenyl-1H-pyrazol-5-amine. The latter was prepared from 2,4-dichlorophenylaceton itrile and ethyl benzoate through Claisen condensation and then cyclization with hydrazine hydrate. The crystal structure of the title compound was determined. In addition, the title compound possesses marked inhibition against the proliferation of human lung adenocarcinoma cell line A549 and human gastric cancer cell line MKN45, displaying promising anticancer activities.

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50

Hafez, Hend N., and Abdel-Rhman B. A. El-Gazzar. "Synthesis of pyranopyrazolo N-glycoside and pyrazolopyranopyrimidine C-glycoside derivatives as promising antitumor and antimicrobial agents." Acta Pharmaceutica 65, no. 3 (September 1, 2015): 215–33. http://dx.doi.org/10.1515/acph-2015-0022.

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Abstract As a part of systematic investigation of the synthesis and biological activities of pyrazole analogues linked to various heterocyclic systems, a new series of pyrazolo-N-glycoside derivatives, pyrazolopyranopyrimidine and C-glycoside of pyrazolopyranotriazolo-pyrimidine derivatives was synthesized through the reaction of the key intermediate 6-amino-3-methyl-4-(substituted-phenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (3a,b) with different reagents. Structures of the newly synthesized compounds were elucidated by elemental microanalysis and spectroscopic methods. The compounds were subjected to in vitro antitumor evaluation using the MTT assay. N-(β-D-ribofuranosyl)- and N-(β-D-xylofuranosyl)-6{[(1E)-4-chlorophenyl)-methylene] amino}4-(4-florophenyl)-3-methyl-1,4-dihydropyrano[2,3-c]-pyrazole-5-carbonitrile (6a,b) were the most active compounds against three human cancer cell lines. Also, most of the newly synthesized compounds exhibited high activity towards Gram-negative and Gram-positive bacteria. Compound 6a exhibited excellent activity towards bacteria compared to ofloxacine as the reference drug.

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