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Journal articles on the topic 'Pyrazolo[3'

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Published: 4 June 2021

Last updated: 26 July 2025

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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

M., K. A. IBRAHIM, H. H. ELGHANDOUR A., S.M. ABDBL-SAYED G., and S.M. ABDEL FATTAH A. "Synthesis of Pyrazoles and Fused Pyrazoles. Novel Synthesis of Pyrano[2,3-c]pyrazole, Thieno[2,3-c]pyrazole and Pyrazolo[3,4-b ]pyridine Derivatives." Journal of Indian Chemical Society Vol. 74, Mar 1997 (1997): 206–8. https://doi.org/10.5281/zenodo.5885902.

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Department of Chemistry, Faculty of Science, Cairo University, Giza, A. R. Egypt <em>Manuscript received 17 November 1994, revised 26 July 1995, accepted 28 September 1995</em> 3-Metbyl-1-thiocarbamoylpyrazoi-5-one (1) reacted with <em>p</em>-metbylpbenscyl bromide to give 3-metbyl-1(4-tbiazol-2-yl)pyrazol-5-one (2). Compounds 1 and 2 were reacted with reagents such as α-cyanocinnamo. benzaldehyde, elemental suJphurlmalononltrlle, benzenediazomum chloride, pyrazol-5-yl-diazonium chloride malononitriie, and ethyl acetoacetate to afford pyrano[2,3-<em>c</em>]pyrazoles (4, 6) Pyra

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3

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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4

Edrees, Mastoura M. "Synthesis of 4-hydrazinopyrazolo[3,4-d]pyrimidines and their Reactions with Carbonyl Compounds." Journal of Chemical Research 37, no. 1 (2013): 6–10. http://dx.doi.org/10.3184/174751912x13543818811749.

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Synthesis of a new 4-hydrazinopyrazolo[3,4- d]pyrimidine was achieved via heating (4,6-dithioxo-1 H-pyrazolo[3,4- d] pyrimidin-3-yl)acetonitrile with hydrazine hydrate. Reactions of the latter product with thiophene-2-carbaldehyde and ethyl hydrazonoacetoacetate analogues afforded the corresponding hydrazone and pyrazole derivatives, respectively. Similarly, condensation of 2-[6-(benzylsulfanyl)-4-hydrazino-1 H-pyrazolo[3,4- d]pyrimidin-3-yl]acetonitrile with thiophene-2-carbaldehyde and ethyl hydrazonoacetoacetate analogues gave the respective hydrazone and pyrazolone derivatives. Alkylation

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5

I.H. El-Qaliei, Mohamed, Sayed A.S. Mousa, Esam A. Ishak, Hamdi M.D. Nasr, Modather F Hussein, and Abdallah M.A. Hassane. "Synthesis, characterization, antimicrobial, antioxidant activities, and in silico study of new azo disperse dyes containing pyrazole and pyrazolo[1,5-a]pyrimidine rings." Bulletin of the Chemical Society of Ethiopia 39, no. 7 (2025): 1411–24. https://doi.org/10.4314/bcse.v39i7.13.

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New N,N-dimethyl-N'-(5-oxo-4-(aryldiazenyl)-2,5-dihydro-1H-pyrazol-3-yl)formimidamide 5a-c are formed by reaction of 5-amino-1H-pyrazol-3(2H)-one derivatives 4a-c with N,N-dimethylformamide dimethyl acetal (DMF-DMA). Compounds 5a-c serve as excellent precursors for the synthesis of new disazo pyrazole disperse dyes, When refluxed with hydrazine hydrate or active methylene reagents 8a,b, leading to N''-(3-hydroxy-4-(arylaza)-1H-pyrazol-5-yl)formimidohydrazide 7a-c or pyrazolo[1,5-a]. pyrimidines 11a–e. In vitro studies were carried out to evaluate antioxidant properties of the produced compound

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6

M., K. A. IBRAHIM, H. H. ELGHANDOUR A., ABOU-HADEED K., and S. ABDELHAFIZ I. "Utility of Hydrazidoyl Chlorides : Synthesis of New Pyrazoles, Pyrazolo[ 3,4-d]pyridazines, Pyrazolo[4,5-b]pyridines and Pyrazolo[ 4,5-d]pyrimidine Derivatives." Journal of Indian Chemical Society Vol. 69, Jul 1992 (1992): 378–80. https://doi.org/10.5281/zenodo.6004337.

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Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt Chemistry Department, Faculty of Science. Suez-Canal University, Ismalia, Egypt <em>Manuscript received 28 October 1991 revised 26 May 1992, accepted 3 June 1992</em> Hydrazidoyl chlorides (1) were reacted with a variety of active methylene compounds and arylidemnialononitriles .1 medium, to produce polyfunctionally substituted pyrazole derivatives (2-6 and 10). The pyrazoles (2, 3, 6 and 10) were converted into the corresponding pyrazolo[3, 4-<em>d</em>]pyridazine derivatives (7 - 9 and 14), respectively. The aminopyraiol

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7

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 (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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8

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 (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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9

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 (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

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10

M., K. A. IBRAHIM, M. EL-REEDY A., S. EL-GHARIE M., and M. FARAG A. "Activated Nitrile in Heterocyclic Synthesis. A Novel Synthesis of Pyrazolo[3,4-b]pyridine, Pyrrolo[2, 3 -c ]pyrazole, Pyrano[2,-3c ]pyrazole and Pyrrolo[3,4-c ]pyrazole." Journal of Indian Chemical Society Vol. 64, Jun 1987 (1987): 345–47. https://doi.org/10.5281/zenodo.6237953.

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Chemistry Department, Faculty of Science, Cairo University, Giza, A. R. Egypt <em>Manuscript received 14 Match 1986, revised 4 November 1986, accepted 22 April 1987</em> The hydrazidoyl halides (2a — c) react with 2- amino-l,1,3-tricyano-1-propene (1a), diethyl 3-amino-2-cyano-2-pentene-1,5-dicarboxylate (1b), 3-iminobutaronitrile (1c), succinonitrile, 1,3 dicyano-2-iminopropane and 1,3-dicyanoacetone in sodium ethoxide solution to give the corresponding pyrazolo[3,4-<em>b</em>]pyridine (6), pyrano[2,3-<em>c</em>]pyrazole (7), pyrazole (10), pyrrolo[2,3-<em>c</em>]pyrazole (11), pyrazolo

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11

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 (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-

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12

Razmienė, Beatričė, Eva Řezníčková, Vaida Dambrauskienė, et al. "Synthesis and Antiproliferative Activity of 2,4,6,7-Tetrasubstituted-2H-pyrazolo[4,3-c]pyridines." Molecules 26, no. 21 (2021): 6747. http://dx.doi.org/10.3390/molecules26216747.

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A library of 2,4,6,7-tetrasubstituted-2H-pyrazolo[4,3-c]pyridines was prepared from easily accessible 1-phenyl-3-(2-phenylethynyl)-1H-pyrazole-4-carbaldehyde via an iodine-mediated electrophilic cyclization of intermediate 4-(azidomethyl)-1-phenyl-3-(phenylethynyl)-1H-pyrazoles to 7-iodo-2,6-diphenyl-2H-pyrazolo[4,3-c]pyridines followed by Suzuki cross-couplings with various boronic acids and alkylation reactions. The compounds were evaluated for their antiproliferative activity against K562, MV4-11, and MCF-7 cancer cell lines. The most potent compounds displayed low micromolar GI50 values. 4

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13

M. Mohareb, Rafat, Maher H.E. Helal, Amany E. Mayhoub, and Amira E.M. Abdallah. "Multi-component reactions for the synthesis of pyrazolo [1,5-a]quinoline derivatives together with their cytotoxic evaluations." Bulletin of the Chemical Society of Ethiopia 37, no. 3 (2023): 717–34. http://dx.doi.org/10.4314/bcse.v37i3.14.

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ABSTRACT. A new approaches for the synthesis of novel pyrazolo[1,5-a]quinazoline 8a-f and pyrazolo[1,5-a]quinazolin-6-one 10a-s and 12a-s derivatives were obtained using 4-(2-phenylhydrazono)-4H-pyrazol-3-amine derivatives 5a-f via their multi-component reactions. The later pyrazole derivatives were prepared via arylhydrazone derivatives 3a-f. The structures of the synthesized compounds were established based on their respective analytical data. On the other hand, the cytotoxic effects of the synthesized compounds were obtained against the six cancer cell lines, namely A549, HT-29, MKN-45, U87

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14

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 be

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15

Çetin, Adnan, Ishak Bildirici, and Selçuk Gümüş. "Novel Pyrazole Derivatives Having Mono/Di Chiral Centered Group as Organocatalyst for Henry Reaction." Macedonian Journal of Chemistry and Chemical Engineering 39, no. 1 (2020): 17. http://dx.doi.org/10.20450/mjcce.2020.1954.

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The chiral substituted pyrazole-3-carboxamides (4a-c), pyrazole-3-carboxylates (5a-c), pyrazole-3-thioureides (7a-c) and pyrazole-3,4-dicarboxamides (10a-c) were prepared via the pyrazolo-3-chlorocarbonyl 2, pyrazolo-3,4-dicarboxy methyl ester 3 with pyrazole-3-isothiocyanate 6 with different (R)-chiral amino alcohols. All of the synthesized chiral compounds binding a pyrazole skeleton were investigated as organocatalysts for asymmetric aldol reactions between nitromethane and p-nitrobenzaldehyde in the presence of CuCl. Enantiomeric excesses and the reaction yields were found to be appropriat

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16

Dmitrieva, I. G., V. K. Vasilin, V. V. Dotsenko, and N. A. Aksenov. "6-(Pyrazol-1-yl)pyrazolo[3,4-b]pyridines: Synthesis, Structure, and Wheat Growth Regulating Activity." Russian Journal of General Chemistry 94, no. 10 (2024): 2603–15. http://dx.doi.org/10.1134/s1070363224100050.

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Abstract 4-Methyl-6-pyrazolyl-2-chloronicotinonitriles were synthesized by the reaction of 6-hydrazino-4-methyl-2-chloronicotinonitriles with 1,3-diketones. Upon treatment with hydrazine and methylhydrazine, 4-methyl-6-pyrazolyl-2-chloronicotinonitriles were converted into the corresponding 3-amino-4-methyl-6-pyrazolyl-1H-pyrazolo[3,4-b]pyridines. A similar reaction involving 1,1-dimethylhydrazine and ethylhydrazine was accompanied by elimination of the alkyl substituent and also led to the formation of 3-amino-6-pyrazolyl-1H-pyrazolo[3,4-b]pyridines. Acylation and carbamoylation of the prepar

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17

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 synth

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18

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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19

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 fo

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20

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 (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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21

Vydzhak, Roman N., and Svitlana Yа Panchishin. "Synthesis of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles." Ukrainica Bioorganica Acta 19, no. 2 (2024): 10–20. https://doi.org/10.15407/bioorganica2024.02.010.

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Preparative method for the preparation of 2-aminoethyl derivatives of pyrazolo[4,3-c]pyrazoles is presented. Alkylation of 1-alkyl-3-methyl-1,4-dihydropyrazolo[4,3-c]pyrazoles with 2-(2-bromomethyl)-1H-isoindole-1,3(2H)-dione and chloroacetonitrile was carried out. In all cases, mixtures of isomeric products of 1- and 2-alkylation with isomer ratios of 1 : 0.8 were obtained. The mixtures of isomers were separated by chromatography and the target compounds did not contain impurities of another isomer. All phthalimide derivatives of pyrazolo[4,3-c]pyrazoles were converted into the corresponding

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22

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 (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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23

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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24

Abdelhamid, Abdou O., and Sobhi M. Gomha. "Synthesis of New Pyrazolo[1,5-a]pyrimidine, Triazolo[4,3-a]pyrimidine Derivatives, and Thieno[2,3-b]pyridine Derivatives from Sodium 3-(5-Methyl-1-phenyl-1H-pyrazol-4-yl)-3-oxoprop-1-en-1-olate." Journal of Chemistry 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/327095.

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Condensation of sodium 3-oxo-3-(1-phenyl-1H-pyrazol-4-yl)prop-1-en-1-olate (2) with several heterocyclic amines, cyanoacetamide, cyanothioacetamide, and 2-cyanoacetohydrazide gives pyrazolo[1,5-a]pyrimidines (5a–d), pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine (9), benzo[4,5]imidazo[1,2-a]pyrimidine (10), [1,2,4]triazolo[1,5-a]pyrimidine (11), and pyridine derivatives (12–14). Also, thieno[2,3-b]pyridines (15–18) were synthesized via pyridinethione (13) withα-halo ketones andα-halo ester. Structures of the newly synthesized compounds were elucidated by elemental analysis, spectral data, alternat

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25

Yin, Xuelian, and Yang-Heon Song. "5-Methyl-1-phenyl-3-(thieno[2,3-d]pyrimidin-4-yl)chromeno[4,3-d]pyrazolo[3,4-b]pyridin-6(3H)-one." Molbank 2022, no. 4 (2022): M1469. http://dx.doi.org/10.3390/m1469.

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A chromeno[4,3-d]pyrazolo[3,4-b]pyridinone derivative 3 bearing thieno[2,3-d]pyrimidine moiety, 5-methyl-1-phenyl-3-(thieno[2,3-d]pyrimidin-4-yl)chromeno[4,3-d]pyrazolo[3,4-b]pyridin-6(3H)-one, was efficiently prepared in 75% yield by the reaction of 3-phenyl-1-(thieno[2,3-d]pyrimidin-4-yl)-1H-pyrazol-5-amine 1 with 3-acetyl-2H-chromen-2-one 2 in the presence of FeCl3-SiO2 as a catalyst in refluxing ethanol for 6 h. The structure of the new synthesized compound was characterized by 1H-, 13C- NMR, IR spectroscopy, mass-spectrometry, and elemental analysis.

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26

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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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-

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Mohareb, Rafat M., Maher H. E. Helal, Amany E. Mayhoub, and Amira E. M. Abdallah. "Multi-component synthesis of pyrazolo[1,5-a]quinazoline, thiazole and thiophene derivatives as cytotoxic agents." Bulletin of the Chemical Society of Ethiopia 37, no. 6 (2023): 1521–38. http://dx.doi.org/10.4314/bcse.v37i6.17.

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ABSTRACT. This study demonstrated the synthesis of a number of pyrazolo[1,5-a]quinazoline derivatives about 24 products based on the starting material 4-(2-phenylhydrazono)-4H-pyrazol-3-amine derivatives 1a-f. Moreover, other ring systems including thiophene, pyrazole, thiazole and pyran (16 compounds) were prepared based on another starting compounds 2-(furan-2-ylmethylene)cyclohexane-1,3-dione 10 and 5,5-dimethyl-3-phenyl-2-thioxo-2,3,5,6-tetrahydrobenzo[d]thiazol-7(4H)-one 18. The multi-component reaction was used to prepare all the previous compounds. The structures of all the synthesised

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29

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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30

Dzedulionytė, Karolina, Melita Veikšaitė, Vít Morávek, et al. "Convenient Synthesis of N-Heterocycle-Fused Tetrahydro-1,4-Diazepinones." Molecules 27, no. 24 (2022): 8666. http://dx.doi.org/10.3390/molecules27248666.

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A general approach towards the synthesis of tetrahydro-4H-pyrazolo[1,5-a][1,4]diazepin-4-one, tetrahydro[1,4]diazepino[1,2-a]indol-1-one and tetrahydro-1H-benzo[4,5]imidazo[1,2-a][1,4]diazepin-1-one derivatives was introduced. A regioselective strategy was developed for synthesizing ethyl 1-(oxiran-2-ylmethyl)-1H-pyrazole-5-carboxylates from easily accessible 3(5)-aryl- or methyl-1H-pyrazole-5(3)-carboxylates. Obtained intermediates were further treated with amines resulting in oxirane ring-opening and direct cyclisation—yielding target pyrazolo[1,5-a][1,4]diazepin-4-ones. A straightforward tw

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31

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 (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 (orth

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32

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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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 (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 propertie

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34

Fesenko, Anastasia A., and Anatoly D. Shutalev. "Unprecedented synthesis of a 14-membered hexaazamacrocycle." Beilstein Journal of Organic Chemistry 19 (November 15, 2023): 1728–40. http://dx.doi.org/10.3762/bjoc.19.126.

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The transformation of 3-[(ethoxymethylene)amino]-1-methyl-1H-pyrazole-4-carbonitrile into the 14-membered macrocycle, 2,10-dimethyl-2,8,10,16-tetrahydrodipyrazolo[3,4-e:3',4'-l][1,2,4,8,9,11]hexaazacyclotetradecine-4,12-diamine, by the reaction with excess hydrazine under various conditions was studied in detail. The reaction proceeded through the initial formation of 4-imino-2-methyl-2,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5-amine followed by dimerization to give the final macrocycle. A convenient synthesis of the latter starting from 4-imino-2-methyl-2,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5

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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]iso

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36

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 se

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37

Shams, H. Z., M. H. Helal, and F. A. Mohamed. "A NOVEL SYNTHESIS OF POLYFUNCTIONALLY SUBSTITUTED PYRAZOLO [1,2=a]PYRAZOLE, AND THIENO [3′,2′-3,4]PYRAZOLO [1,2-a]PYRAZOLE SYSTEMS." Phosphorus, Sulfur, and Silicon and the Related Elements 174, no. 1 (2001): 255–67. http://dx.doi.org/10.1080/10426500108040250.

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38

Hasan, Muhammad, Anatoly A. Peshkov, Syed Anis Ali Shah, et al. "Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines." Beilstein Journal of Organic Chemistry 21 (May 8, 2025): 915–25. https://doi.org/10.3762/bjoc.21.74.

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A silver(I) triflate-catalyzed post-Ugi assembly of novel pyrazolo[1,5-a][1,4]diazepine scaffolds is reported offering high yields (up to 98%) under mild conditions. The synthetic sequence involves the Ugi four-component reaction (U4CR) of pyrazole-3-carbaldehydes, primary amines, 3-substituted propiolic acids, and isocyanides, followed by a silver(I) triflate-catalyzed intramolecular heteroannulation of the resulting pyrazole-tethered propargylamides occurring in a 7-endo-dig fashion. The approach is scalable and tolerates a diverse range of substitution patterns.

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39

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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40

Polo, Efraín, Valentina Arce-Parada, Xaviera A. López-Cortés, et al. "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 (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

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41

M., B. Deshmukh, A. Deshmukh S., S. Jagtap S., W. Suryavanshi A., Jadhav S.D., and V. Anbhule P. "Synthesis and antimicrobial activity of pyridopyrazole and pyrazolo[3,4-d]dihydrothiazole." Journal of Indian Chemical Society Vol. 86, Jun 2009 (2009): 613–16. https://doi.org/10.5281/zenodo.5811785.

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Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra, India <em>E-mail</em>: m_deshmukhl@rediffmail.com <em>Manuscript received 30 July 2007, revised 2 January 2009, accepted 27 February 2009</em> 6-Methyl-1,3-dihydro-4<em>H,</em>7<em>H</em>-pyrazolo[2,3-c)pyridine-4-one (4) were synthesized by microwave as well as conventional method. The reaction time reduced 10 times than that of conventional method. The pyrazolo[3,4-<em>d</em>]dihydrothiazole (8) were synthesized by reacting phenylisothiocyanate with 1-carbethoxy-5-amino-pyrazol-4-ene-3- one and were screened for thei

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42

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 (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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43

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 (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.

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44

Azam, Mohammed Afzal, Loganathan Dharanya, Charu Chandrakant Mehta, and Sumit Sachdeva. "Synthesis and biological evaluation of some novel pyrazolopyrimidines incorporating a benzothiazole ring system." Acta Pharmaceutica 63, no. 1 (2013): 19–30. http://dx.doi.org/10.2478/acph-2013-0001.

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In the present study, a series of benzothiazol derivatives 3a-l containing pyrazolo[3,4-d]pyrimidine moiety at the second position were synthesized and characterized by analytical and spectral data. The compounds were tested for their in vitro antimicrobial activity. Compounds 1-(1,3-benzothiazol-2- yl)-3-methyl-4-phenyl-1H-pyrazolo[3,4-d]pyrimidine (3a), 1- (1,3-benzothiazol-2-yl)-4-(4-chlorophenyl)-3-methyl-1H-pyrazolo[ 3,4-d]pyrimidine (3d) and 1-(1,3-benzothiazol-2-yl)- 3-methyl-4-substituted phenyl-1H-pyrazolo[3,4-d]pyrimidines (3h-j) showed significant inhibitory activity against P. aeru

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45

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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46

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 (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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47

Galarraga, Elier, Neudo Urdaneta, Keily J. Gutierrez, and Julio C. Herrera. "In vitro cytotoxicity of hydrazones, pyrazoles, pyrazolo-pyrimidines, and pyrazolo-pyridine synthesized from 6-substituted 3-formylchromones." Zeitschrift für Naturforschung B 70, no. 5 (2015): 305–10. http://dx.doi.org/10.1515/znb-2014-0236.

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AbstractPyrazoles 4a–f, hydrazones 5a–c and 6a–c, pyrazolo[1,5-a]pyrimidines 7a, b, and pyrazolo[3,4-b]pyridine 8 were prepared in good yields (80–95 %) from the reaction of 6-substituted (H, Me, F) 3-formylchromones 1a–c with N-substituted hydrazines 2a–c and aminopyrazole 3. The cytotoxicity of the synthesized compounds was assessed through the brine shrimp lethality assay. IC50 values were between 80 and 300 μm. Fluorine substitution decreased IC50 values.

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48

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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49

Rádl, Stanislav, and Viktor Zikán. "Syntheses of some 4-dialkylaminoalkylamino derivatives of 2,3-dimethyl-2H- and 3,9-dimethyl-9H-pyrazolo[3,4-b]quinoline." Collection of Czechoslovak Chemical Communications 51, no. 8 (1986): 1692–97. http://dx.doi.org/10.1135/cccc19861692.

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Reactions of 4-chloro-2,3-dimethyl-2H-pyrazolo[3,4-b]quinoline and 4-chloro-6-methoxy-2,3-dimethyl-2H-pyrazolo[3,4-b]quinoline with 3-dimethylaminopropylamine and/or 2-dimethylaminoethylamine afforded 4-(3-dimethylaminopropylamino)-2,3-dimethyl-2H-pyrazolo[3,4-b]quinoline (IIa), its 6-methoxy derivative (IIc), 4-(2-diethylaminoethylamino)-2,3-dimethyl-2H-pyrazolo[3,4-b]quinoline (IIb) and its 6-methoxy derivative (IId). Reaction of 4,9-dihydro-3,9-dimethyl-4-oxo-1H-pyrazolo[3,4-b]quinoline with thionyl chloride gave an intermediate, whose reaction with 3-dimethylaminopropylamine afforded 4-(3-

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50

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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