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Journal articles on the topic 'Pyrazolones'

Author: Grafiati

Published: 4 June 2021

Last updated: 7 September 2023

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1

Gediz Erturk, Aliye, and Hilal Omerustaoglu. "Synthesis and Cytotoxic Evaluation of Some Substituted 5-Pyrazolones and Their Urea Derivatives." Molecules 25, no. 4 (February 18, 2020): 900. http://dx.doi.org/10.3390/molecules25040900.

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In this paper, a series of new substituted-5-pyrazolones were first synthesized, then formulated by the Vilsmeier–Haack reaction to obtain substituted-4-carbaldehyde-5-pyrazolones. In the final step, when urea was reacted with formulated pyrazolones, we found that, instead of the C=N bond in azomethine form, the compounds tautomerized to form a series of novel pyrazole-4-ylidenemethylurea structures. The structures of these compounds were elucidated by FTIR, 1H, 13C NMR, LC-MS/MS, and elemental analysis methods. The cytotoxic and antioxidant effects of substituted 5-pyrazolones and their pyrazolone-urea derivatives were investigated in metastatic A431 and noncancerous HaCaT human keratinocytes by a mitochondrial activity test. The effects of the compounds on the migration of cancerous and noncancerous cell lines were investigated by using a cell scratch assay. The General Linear Model, Statistical Package for Social Sciences (SPSS v26) was used to determine if there was a statistically significant difference between the control and the treatment groups. Four of the nine compounds showed an antioxidant effect. All 5-pyrazolone-urea compounds showed higher toxicity (p < 0.05) in cancerous A431 cells compared to noncancerous cells at all time points. All compounds also showed a biphasic hormetic effect. Four of the nine compounds inhibited cell migration.

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2

Sun, Jun-Shu, Ying-Ying Wang, Man Liu, Jing Zhang, Chen-Fei Liu, Yan-Jun Xu, and Lin Dong. "Construction of pyrazolone analogues via rhodium-catalyzed C–H activation from pyrazolones and non-activated free allyl alcohols." Organic Chemistry Frontiers 6, no. 15 (2019): 2713–17. http://dx.doi.org/10.1039/c9qo00504h.

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3

Yang, Kai, Xiaoze Bao, Ye Yao, Jingping Qu, and Baomin Wang. "Iodine-mediated cross-dehydrogenative coupling of pyrazolones and alkenes." Organic & Biomolecular Chemistry 16, no. 34 (2018): 6275–83. http://dx.doi.org/10.1039/c8ob01645c.

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4

Zhang, Wande, Shah Nawaz, Yue Huang, Wenjing Gong, Xingfu Wei, Jingping Qu, and Baomin Wang. "C-4 benzofuranylation of pyrazolones by a metal-free catalyzed indirect heteroarylation strategy." Organic & Biomolecular Chemistry 19, no. 46 (2021): 10215–22. http://dx.doi.org/10.1039/d1ob01920a.

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A metal-free catalyzed indirect heteroarylation of pyrazolones with 2-(3-hydroxy-3,3-diarylprop-1-yn-1-yl)phenols has been developed, delivering a wide range of novel 4-benzofuran-substituted pyrazolone derivatives.

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5

Wei, Shiqiang, Xiaoze Bao, Wenyao Wang, Shah Nawaz, Qimin Dai, Jingping Qu, and Baomin Wang. "Enantioselective construction of dispirotriheterocycles featuring a 4-aminopyrazolone motif through a cascade Michael/cyclization process." Chemical Communications 56, no. 73 (2020): 10690–93. http://dx.doi.org/10.1039/d0cc04215c.

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A highly asymmetric approach to multicyclic dispiro [pyrazolone-pyrrolidinethione-oxindole] core structures bearing three contiguous stereogenic centers through a cascade Michael addition/cyclization reaction of 4-isothiocyanato pyrazolones with 3-ylideneoxindoles was developed.

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6

Pattan, S. R., P. A. Chavan, R. A. Muluk, S. S. Dengale, S. V. Hiremath, K. D. Pansare, S. S. Vetal, and J. S. Pattan. "SYNTHESIS AND BIOLOGICAL EVALUATION OF SOME HETEROCYCLES CONTAINING OXADIAZOLE AND PYRAZOLE RING FOR ANTI-BACTERIAL, ANTI-FUNGAL AND ANTI-TUBERCULAR ACTIVITIES." INDIAN DRUGS 49, no. 03 (March 28, 2012): 18–24. http://dx.doi.org/10.53879/id.49.03.p0018.

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1, 3, 4-oxadiazoles were synthesized by treating pyrazine-2-carbohydrazide with CS2 and alc. KOH and their derivatives were prepared by using R-Cl compounds. pyrazolones were synthesized by treatingpyrazine-2-carbohydrazide with ethyl acetoacetate. The derivatives of pyrazolone were prepared by refluxing pyrazolone with formaldehyde and different substituted secondary amines. All the synthesized compounds were characterized by IR, 1H-NMR and elemental analysis and evaluated for antibacterial, antifungal and antitubercular activities.

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7

Kashinath, Dhurke, Kota Sathish, and Sakkani Nagaraju. "Synthesis of Spiro Pyrazolone-Oxindole and Bicyclic Pyrazolone Derivatives via Solvent-Dependent Regioselective Aza-1,4/1,6-Michael and Intramolecular Cycloaddition under Catalyst-Free Conditions." SynOpen 05, no. 02 (April 13, 2021): 123–33. http://dx.doi.org/10.1055/a-1480-9837.

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AbstractA solvent-dependent, highly regioselective [3+2]-cycloaddition reaction of isoxazole-styrenes and azomethine imines under catalyst-free conditions is reported, furnishing a library of pyrazolone–spirooxindole hybrids. Good regioselectivity for the isomeric structures was achieved by the reaction of isoxazole-styrene and azomethine imine in different solvents and temperatures. The developed method was extended for the synthesis of tri-substituted dinitrogen-fused pyrazolones by using a 1,6-Michael addition reaction. Furthermore, the isoxazole moiety was converted into a carboxylic acid as a model study via ring opening.

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8

Hassan, Abdalla E. A., Ahmed H. Moustafa, Mervat M. Tolbah, Hussein F. Zohdy, and Abdelfattah Z. Haikal. "Synthesis and Antimicrobial Evaluation of Novel Pyrazolones and Pyrazolone Nucleosides." Nucleosides, Nucleotides and Nucleic Acids 31, no. 11 (November 2012): 783–800. http://dx.doi.org/10.1080/15257770.2012.732250.

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9

Zhao, Xia, Xiaoyu Lu, Lipeng Zhang, Tianjiao Li, and Kui Lu. "One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water." Current Organic Synthesis 15, no. 3 (April 27, 2018): 380–87. http://dx.doi.org/10.2174/1570179414666171020113745.

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Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

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10

Chu, Ming-Ming, Suo-Suo Qi, Yi-Feng Wang, Biao Wang, Zhen-Hui Jiang, Dan-Qian Xu, and Zhen-Yuan Xu. "Organocatalytic asymmetric [4 + 1] annulation of in situ generated ortho-quinomethanes with 4-halo pyrazolones: straightforward access to chiral spiro-benzofuran pyrazolones." Organic Chemistry Frontiers 6, no. 12 (2019): 1977–82. http://dx.doi.org/10.1039/c9qo00332k.

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11

Wang, Wenyao, Shiqiang Wei, Xiaoze Bao, Shah Nawaz, Jingping Qu, and Baomin Wang. "Enantioselective [3 + 2] annulation of 4-isothiocyanato pyrazolones and alkynyl ketones under organocatalysis." Organic & Biomolecular Chemistry 19, no. 5 (2021): 1145–54. http://dx.doi.org/10.1039/d0ob02423f.

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12

Zhang, Wande, Shiqiang Wei, Jingping Qu, and Baomin Wang. "Acid-catalyzed allenylation of pyrazolones with propargyl alcohols." Organic & Biomolecular Chemistry 19, no. 22 (2021): 4992–5001. http://dx.doi.org/10.1039/d1ob00592h.

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13

Pedro, José R., Carlos Vila, Laura Carceller-Ferrer, and Gonzalo Blay. "Recent Advances in Catalytic Enantioselective Synthesis of Pyrazolones with a Tetrasubstituted Stereogenic Center at the 4-Position." Synthesis 53, no. 02 (October 8, 2020): 215–37. http://dx.doi.org/10.1055/s-0040-1707298.

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AbstractPyrazolone [2,4-dihydro-3H-pyrazol-4-one] represents one of the most important five-membered nitrogen heterocycles which is present in numerous pharmaceutical drugs and molecules with biological activity. Recently, many catalytic methodologies for the asymmetric synthesis of chiral pyrazolones have been established with great success, specially, for the synthesis of pyrazolones bearing a tetrasubstituted stereocenter at C-4. This review summarizes these excellent research studies since 2018, including representative examples and some mechanistic pathways explaining the observed stereochemistry.1 Introduction2 Catalytic Enantioselective Synthesis of Chiral Pyrazolones with a Full Carbon Tetrasubstituted Stereocenter at C-43 Catalytic Enantioselective Synthesis of Chiral Pyrazolones with a Quaternary Carbon Stereocenter at C-4 bearing a Heteroatom4 Catalytic Enantioselective Synthesis of Chiral Spiropyrazolones5 Conclusion

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14

Geng, Jianqi, Xingfu Wei, Biru He, Yuting Hao, Jingping Qu, and Baomin Wang. "Desymmetrization of Prochiral N-Pyrazolyl Maleimides via Organocatalyzed Asymmetric Michael Addition with Pyrazolones: Construction of Tri-N-Heterocyclic Scaffolds Bearing Both Central and Axial Chirality." Molecules 28, no. 11 (May 23, 2023): 4279. http://dx.doi.org/10.3390/molecules28114279.

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The desymmetrization of N-pyrazolyl maleimides was realized through an asymmetric Michael addition by using pyrazolones under mild conditions, leading to the formation of a tri-N-heterocyclic pyrazole–succinimide–pyrazolone assembly in high yields with excellent enantioselectivities (up to 99% yield, up to 99% ee). The use of a quinine-derived thiourea catalyst was essential for achieving stereocontrol of the vicinal quaternary–tertiary stereocenters together with the C–N chiral axis. Salient features of this protocol included a broad substrate scope, atom economy, mild conditions and simple operation. Moreover, a gram-scale experiment and derivatization of the product further illustrated the practicability and potential application value of this methodology.

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15

Awasthi, Annapurna, Pushpendra Yadav, and Dharmendra Kumar Tiwari. "A three-component, general and practical route for diastereoselective synthesis of aza-spirocyclic pyrazolones via a decarboxylative annulation process." New Journal of Chemistry 45, no. 5 (2021): 2374–83. http://dx.doi.org/10.1039/d0nj05915c.

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An efficient, general, and practical route for highly diastereoselective synthesis of aza-spirocyclic pyrazolones from easily available α-amino acids, aldehydes, and alkylidene pyrazolones by means of a decarboxylative annulation process is reported.

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16

Mukherjee, Prasun, and Asish R. Das. "One-flask synthesis of pyrazolone thioethers involving catalyzed and uncatalyzed thioetherification pathways of pyrazolones." Organic & Biomolecular Chemistry 15, no. 35 (2017): 7267–71. http://dx.doi.org/10.1039/c7ob01754e.

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17

Levy, M. "Hypersensitivity to pyrazolones." Thorax 55, no. 90002 (October 1, 2000): 72S—74. http://dx.doi.org/10.1136/thorax.55.suppl_2.s72.

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18

Hassan, Abdalla E. A., Ahmed H. Moustafa, Mervat M. Tolbah, Hussein F. Zohdy, and Abdelfattah Z. Haikal. "ChemInform Abstract: Synthesis and Antimicrobial Evaluation of Novel Pyrazolones and Pyrazolone Nucleosides." ChemInform 44, no. 17 (April 4, 2013): no. http://dx.doi.org/10.1002/chin.201317110.

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19

Wang, Yi-Feng, Xue-Yang Chen, Zhen-Hui Jiang, Wan-Zhen Ju, Hao Yin, Suo-Suo Qi, and Ming-Ming Chu. "Asymmetric Chlorination of 4-Substituted Pyrazolones Catalyzed by Chiral Copper Complexes." Synlett 31, no. 13 (March 31, 2020): 1318–22. http://dx.doi.org/10.1055/s-0039-1690879.

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A fast and highly enantioselective chlorination of 4-pyrazolones catalyzed by bis(oxazoline)–Cu(ClO4)2·6H2O complexes has been developed. Under the optimized conditions, a series of pyrazolones bearing stereogenic chlorine-attached carbon centers were obtained in moderate to high yields (up to 98%) and with enantioselectivities of up to 98% ee.

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20

Bingi, Chiranjeevi, Narender Reddy Emmadi, Madhu Chennapuram, Jagadeesh Babu Nanubolu, and Krishnaiah Atmakur. "A simple and catalyst free one pot access to the pyrazolone fused 2,8-dioxabicyclo[3.3.1]nonanes." RSC Adv. 4, no. 66 (2014): 35009–16. http://dx.doi.org/10.1039/c4ra07278b.

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Synthesis of a series of novel aryl and heteroaryl fused 2,8-dioxabicyclo[3.3.1]nonanes (3) was accomplished by one pot, catalyst free reaction of 2-hydroxy chalcones (1) with 3-trifluoromethyl substituted pyrazolones (2) in xylene at reflux temperature. The role of –CF₃ in formation of 3 was confirmed by comparing with 3-methyl pyrazolones.

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21

Nezhad, Shefa Mirani, Seied Ali Pourmousavi, Ehsan Nazarzadeh Zare, Golnaz Heidari, and Pooyan Makvandi. "Magnetic Sulfonated Melamine-Formaldehyde Resin as an Efficient Catalyst for the Synthesis of Antioxidant and Antimicrobial Pyrazolone Derivatives." Catalysts 12, no. 6 (June 7, 2022): 626. http://dx.doi.org/10.3390/catal12060626.

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Sulfonated polymer-based materials, among heterogeneous catalysts, are frequently utilized in chemical transformations due to their outstanding chemical and physical durability. In this regard, a magnetic sulfonated melamine–formaldehyde resin (MSMF) catalyst was successfully prepared from a mixture of sulfonated melamine–formaldehyde and Fe3O4 nanoparticles in two steps. MSMF was used as a heterogeneous catalyst for the one-pot, three-component condensation of benzyl pyrazolyl naphthoquinones in water as a green solvent and 4-[(indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolones. The antimicrobial and antioxidant activities of catalyst, benzyl pyrazolyl naphthoquinones, and 4-[(indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolones were evaluated using agar disk-diffusion and DPPH assays, respectively. The antioxidant activity of the catalyst and 4-[(indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolones was found to be 75% and 90%, respectively. Furthermore, catalyst, benzyl pyrazolyl naphthoquinones, and 4-[(indol-3-yl)-arylmethyl]-1-phenyl-3-methyl-5-pyrazolones exhibited antimicrobial activity against Staphylococcus aureus and Escherichia coli. In conclusion, MSMF is a superior catalyst for green chemical processes, owing to its high catalytic activity, stability, and reusability.

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22

Achuthanandhan, Jyothi, and Baskar Lakshmanan. "Docking studies of tetra substituted pyrazolone derivatives as potential antiviral agents." JOURNAL OF PHARMACEUTICAL CHEMISTRY 5, no. 2 (December 20, 2018): 5–8. http://dx.doi.org/10.14805/jphchem.2018.art103.

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In an attempt to find potential antiviral agents, a series of pyrazolones (PA1-PA6& PC1-PC6) were designed and evaluated for their DENVNS5 (RNA-dependent RNA polymerase) inhibitory activity. Molecular docking studies of all the designed compounds into the binding site of DENVNS5 (PDB Code: 4C11) were performed to gain a comprehensive understanding into rational binding modes. These compounds were also screened for in silico drug-likeliness properties on the basis of the absorption, distribution, metabolism and excretion (ADME) prediction. Among all the synthesized compounds, analogue PA6showed superior inhibitory activity against RNA dependent RNA polymerase. SAR study indicated that the presence of an electron withdrawing substitution on pyrazolone derivatives significantly improves its binding interaction with the protein.Results of ADME prediction revealed that most of these compounds showed in silico drug-likeliness.

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23

Yang, Wenjun, Yunpeng Zhang, Shuxian Qiu, Chuanqi Zhao, Lei Zhang, Honglei Liu, Leijie Zhou, Yumei Xiao, and Hongchao Guo. "Phosphine-catalyzed [4 + 2] cycloaddition of unsaturated pyrazolones with allenoates: a concise approach toward spiropyrazolones." RSC Advances 5, no. 77 (2015): 62343–47. http://dx.doi.org/10.1039/c5ra11595g.

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24

Šimek, Michal, Marek Remeš, Jan Veselý, and Ramon Rios. "Enantioselective Organocatalytic Amination of Pyrazolones." Asian Journal of Organic Chemistry 2, no. 1 (December 20, 2012): 64–68. http://dx.doi.org/10.1002/ajoc.201200168.

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25

Guo, Jixi, Li Liu, Dianzeng Jia, Mingxi Guo, Yucai Zhang, and Xianli Song. "Photochromism and fluorescence modulation of pyrazolone derivatives in the solid state." New Journal of Chemistry 39, no. 4 (2015): 3059–64. http://dx.doi.org/10.1039/c4nj01970a.

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26

Wang, Xueli, Xingwei Li, Yao Zhang, and Lixin Xia. "Gold(i)- and rhodium(iii)-catalyzed formal regiodivergent C–H alkynylation of 1-arylpyrazolones." Organic & Biomolecular Chemistry 16, no. 16 (2018): 2860–64. http://dx.doi.org/10.1039/c8ob00585k.

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27

Bao, Xiaoze, Shiqiang Wei, Jingping Qu, and Baomin Wang. "C6′ steric bulk of cinchona alkaloid enables an enantioselective Michael addition/annulation sequence toward pyranopyrazoles." Chemical Communications 54, no. 16 (2018): 2028–31. http://dx.doi.org/10.1039/c8cc00154e.

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28

Warghude, Prakash K., Abhijeet S. Sabale, and Ramakrishna G. Bhat. "Access to highly enantioselective and diastereoselective spirooxindole dihydrofuran fused pyrazolones." Organic & Biomolecular Chemistry 18, no. 9 (2020): 1794–99. http://dx.doi.org/10.1039/d0ob00007h.

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29

Lakshmi, Shanta Raj, Vipin Singh, and L. Raju Chowhan. "Highly efficient catalyst-free domino conjugate addition, decarboxylation and esterification/amidation of coumarin carboxylic acid/esters with pyrazolones: a green chemistry approach." RSC Advances 10, no. 23 (2020): 13866–71. http://dx.doi.org/10.1039/d0ra01906b.

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30

Bao, Xiaoze, Shiqiang Wei, Liwei Zou, Yuli He, Fuzhao Xue, Jingping Qu, and Baomin Wang. "Asymmetric chlorination of 4-substituted pyrazolones catalyzed by natural cinchona alkaloid." Chemical Communications 52, no. 76 (2016): 11426–29. http://dx.doi.org/10.1039/c6cc06236a.

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31

Wei, Ran, Li Gao, Gaihui Li, Li Tang, Guoshun Zhang, Feilang Zheng, Heng Song, Qingshan Li, and Shurong Ban. "Squaramide-catalysed asymmetric Friedel–Crafts alkylation of naphthol and unsaturated pyrazolones." Organic & Biomolecular Chemistry 19, no. 15 (2021): 3370–73. http://dx.doi.org/10.1039/d1ob00347j.

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32

Xiao, Yan, Xiaopeng Wu, Jiangang Teng, Song Sun, Jin-Tao Yu, and Jiang Cheng. "Copper-catalyzed acylation of pyrazolones with aldehydes to afford 4-acylpyrazolones." Organic & Biomolecular Chemistry 17, no. 32 (2019): 7552–57. http://dx.doi.org/10.1039/c9ob01486a.

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33

Krylov, Igor B., Stanislav A. Paveliev, Boris N. Shelimov, Boris V. Lokshin, Irina A. Garbuzova, Viktor A. Tafeenko, Vladimir V. Chernyshev, Alexander S. Budnikov, Gennady I. Nikishin, and Alexander O. Terent'ev. "Selective cross-dehydrogenative C–O coupling of N-hydroxy compounds with pyrazolones. Introduction of the diacetyliminoxyl radical into the practice of organic synthesis." Organic Chemistry Frontiers 4, no. 10 (2017): 1947–57. http://dx.doi.org/10.1039/c7qo00447h.

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34

Liu, Xiaobing, Yao Zhou, and Qiuling Song. "Metal-free cyclization of unsaturated hydrazones for the divergent assembly of pyrazolones and pyrazolines." Chemical Communications 55, no. 61 (2019): 8943–46. http://dx.doi.org/10.1039/c9cc04039k.

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35

Wei, Wei, Huanhuan Cui, Daoshan Yang, Xiaoxia Liu, Chenglong He, Shicui Dai, and Hua Wang. "Metal-free molecular iodine-catalyzed direct sulfonylation of pyrazolones with sodium sulfinates leading to sulfonated pyrazoles at room temperature." Organic Chemistry Frontiers 4, no. 1 (2017): 26–30. http://dx.doi.org/10.1039/c6qo00403b.

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36

Putatunda, Salil, Juan V. Alegre-Requena, Marta Meazza, Michael Franc, Dominika Rohal'ová, Pooja Vemuri, Ivana Císařová, Raquel P. Herrera, Ramon Rios, and Jan Veselý. "Proline bulky substituents consecutively act as steric hindrances and directing groups in a Michael/Conia-ene cascade reaction under synergistic catalysis." Chemical Science 10, no. 14 (2019): 4107–15. http://dx.doi.org/10.1039/c8sc05258a.

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37

Cheng, Cheng, Xiaobin Sun, Zelin Wu, Qianwei Liu, Liqiang Xiong, and Zhiwei Miao. "Lewis base catalyzed regioselective cyclization of allene ketones or α-methyl allene ketones with unsaturated pyrazolones." Organic & Biomolecular Chemistry 17, no. 12 (2019): 3232–38. http://dx.doi.org/10.1039/c9ob00179d.

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38

Liu, Xiaoxia, Huanhuan Cui, Daoshan Yang, Shicui Dai, Tiantian Zhang, Jingyu Sun, Wei Wei, and Hua Wang. "Metal-free direct construction of sulfenylated pyrazoles via the NaOH promoted sulfenylation of pyrazolones with aryl thiols." RSC Advances 6, no. 57 (2016): 51830–33. http://dx.doi.org/10.1039/c6ra09739a.

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39

Carceller-Ferrer, Laura, Carlos Vila, Gonzalo Blay, Isabel Fernández, M. Carmen Muñoz, and José R. Pedro. "Organocatalytic enantioselective aminoalkylation of pyrazol-3-ones with aldimines generated in situ from α-amido sulfones." Organic & Biomolecular Chemistry 17, no. 46 (2019): 9859–63. http://dx.doi.org/10.1039/c9ob02252j.

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40

Yue, Deng-Feng, Jian-Qiang Zhao, Zhen-Hua Wang, Xiao-Mei Zhang, Xiao-Ying Xu, and Wei-Cheng Yuan. "A Neber approach for the synthesis of spiro-fused 2H-azirine-pyrazolone." Organic & Biomolecular Chemistry 14, no. 6 (2016): 1946–49. http://dx.doi.org/10.1039/c5ob02559a.

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41

Maity, Rajendra, and Subhas Chandra Pan. "Enantioselective aminocatalytic synthesis of tetrahydropyrano[2,3-c]pyrazoles via a domino Michael-hemiacetalization reaction with alkylidene pyrazolones." Organic & Biomolecular Chemistry 15, no. 38 (2017): 8032–36. http://dx.doi.org/10.1039/c7ob02170d.

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An enantioselective organocatalytic synthesis of fused tetrahydropyranopyrazole products has been achieved via a domino Michael-hemiacetalization reaction between alkylidene pyrazolones and cyclic ketones/pentanal.

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42

Zheng, Ya-Yun, Kai-Xiang Feng, Ai-Bao Xia, Jie Liu, Cheng-Ke Tang, Zhan-Yu Zhou, and Dan-Qian Xu. "Merging catalyst-free synthesis and iodine catalysis: one-pot synthesis of dihydrofuropyrimidines and spirodihydrofuropyrimidine pyrazolones." RSC Advances 9, no. 17 (2019): 9770–76. http://dx.doi.org/10.1039/c9ra01665a.

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43

Thupyai, Akkharaphong, Chaleena Pimpasri, and Sirilata Yotphan. "DABCO-catalyzed silver-promoted direct thiolation of pyrazolones with diaryl disulfides." Organic & Biomolecular Chemistry 16, no. 3 (2018): 424–32. http://dx.doi.org/10.1039/c7ob02860a.

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44

Sun, Pengfei, Daoshan Yang, Wei Wei, Linhong Jiang, Yuquan Wang, Tongxin Dai, and Hua Wang. "DMSO-promoted regioselective synthesis of sulfenylated pyrazoles via a radical pathway." Organic Chemistry Frontiers 4, no. 7 (2017): 1367–71. http://dx.doi.org/10.1039/c7qo00218a.

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45

Xie, Jin, Xiao-Yu Xing, Feng Sha, Zhi-Yan Wu, and Xin-Yan Wu. "Enantioselective synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives via an organocatalytic asymmetric Michael/cyclization cascade reaction." Organic & Biomolecular Chemistry 14, no. 35 (2016): 8346–55. http://dx.doi.org/10.1039/c6ob01256f.

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46

Wu, Weirong, Yuxia Liu, and Siwei Bi. "Mechanistic insight into conjugated N–N bond cleavage by Rh(iii)-catalyzed redox-neutral C–H activation of pyrazolones." Organic & Biomolecular Chemistry 13, no. 30 (2015): 8251–60. http://dx.doi.org/10.1039/c5ob00977d.

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47

Gong, Hao, Yiwen Yang, Zechao Wang, and Chunxiang Kuang. "An easy direct arylation of 5-pyrazolones." Beilstein Journal of Organic Chemistry 9 (October 8, 2013): 2033–39. http://dx.doi.org/10.3762/bjoc.9.240.

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A mild, efficient and catalytic ligand-free method for the direct arylation of 5-pyrazolones by Pd-catalyzed C–H bond activation is reported. The process smoothly proceeds and yields are moderate to excellent.

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48

Chauhan, Pankaj, Suruchi Mahajan, and Dieter Enders. "Asymmetric synthesis of pyrazoles and pyrazolones employing the reactivity of pyrazolin-5-one derivatives." Chemical Communications 51, no. 65 (2015): 12890–907. http://dx.doi.org/10.1039/c5cc04930j.

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The various catalytic asymmetric strategies employing organo- and metal-catalysts utilized pyrazolin-5-one derivatives for the synthesis of potentially bioactive enantiopure pyrazoles and pyrazolones are presented.

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Koch, Rainer, Hans-Joachim Wollweber, and Curt Wentrup. "Oximes in the Isoxazolone, Pyrazolone, and 1,2,3-Triazolone Series: Experimental and Computational Investigation of Energies and Structures of E/Z Isomers of α-Oxo-Oximes in the Gas Phase and in Solution." Australian Journal of Chemistry 68, no. 9 (2015): 1329. http://dx.doi.org/10.1071/ch15095.

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The structures of a series of heterocyclic α-oxo-oximes, viz. 4-oximinoisoxazolone-5(4H)-ones 1 and 2,4-oximino-5(4H)-pyrazolones 3–5, and 4-oximino-1-phenyl-1,2,3-triazol-5(4H)-one 6, were investigated experimentally and computationally. Whereas the intramolecularly H-bonded ZZ isomers of these oximes are usually the most stable in the gas phase, this preference is overcome by intermolecular H-bonding to a solvent or another molecule. For 1,3-dimethyl-4-oximino-5(4H)-pyrazolone 3b a turnaround is seen when going from the solid (predominantly Z isomer) to DMSO solution (predominantly E isomer), which can be ascribed to an intermolecular H-bond between the oxime OH function and a DMSO molecule. Such isomerization is not seen in CDCl3, where intermolecular H-bonding is unimportant. The Z/E-isomerization in DMSO solution is accelerated by photolysis. Calculations of the energies of different conformers, and of 13C NMR data at the GIAO-ωb97xD/6-31G(d)//M06-2X/6-311++G(d,p) level permit a clear-cut correlation of conformer structures with observed 13C NMR spectra.

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50

Parihar, Sanjay, R. N. Jadeja, and Vivek K. Gupta. "C3 symmetric vanadium(iii) complexes with O,N-chelating hexadentate tripodal ligands of pyrazolone." RSC Adv. 4, no. 83 (2014): 43994–97. http://dx.doi.org/10.1039/c4ra04021j.

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Novel C₃ symmetric vanadium(iii) complexes of tripodal ligands of pyrazolones were synthesized and characterized by various spectroscopic and analytical techniques including single crystal XRD.

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