- Base promoted CuFe2O4 catalyzed one-pot synthesis of 3,5-diaryl-1H-pyrazoles
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Available synthetic protocols for 3,5-diaryl-1H-pyrazoles generally demand long reaction time. Herein, we are reporting a CuFe2O4 catalyzed synthetic procedure for the same that delivers products in significantly reduced time starting from tosylhydrazones of aromatic aldehydes and terminal alkynes. Under the reaction condition, tosylhydrazone generates diazo compound in situ, which then undergoes [3 + 2] cycloaddition reaction with the terminal alkyne followed by [1,3]-H shift to deliver the final products in 72%–85% isolated yield. Magnetically active CuFe2O4 nanoparticles can be recovered very easily after the completion of the reaction and can be reused up to fifth cycle without significant loss in its catalytic activity. Operational simplicity of the methodology along with tolerability of various functional groups as well as easy recovery and high reusability of CuFe2O4 nanoparticles make the procedure a practical and handy one for the synthesis of 3,5-diaryl-1H-pyrazoles.
- Bhuyan, Pubanita,Saikia, Lakhinath
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supporting information
(2021/11/16)
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- Denitrative imino-diaza-Nazarov cyclization: Synthesis of pyrazoles
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An iodine-catalyzed denitrative imino-diaza-Nazarov cyclization (DIDAN) methodology has been developed for the synthesis of pyrazoles with high to excellent yields by using α-nitroacetophenone derivatives and in situ generated hydrazones. The key transformation of this oxidative 4π-electrocyclization proceeds through an enamine-iminium ion intermediate. This rapid one-pot DIDAN protocol results in the selective generation of C-C and C-N bonds and cleavage of a C-N bond. This journal is
- Aegurla, Balakrishna,Jarwal, Nisha,Peddinti, Rama Krishna
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p. 6100 - 6107
(2020/10/21)
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- Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3-Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
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3-(Hetero)aryl propenals or propenones are efficiently prepared by a Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using Beller's CataCXium Ptb ligand under Jeffery's and Fu's conditions. The formation of these three-carbon building blocks is embedded into consecutive three- and pseudo-four-component syntheses of 3-(hetero)aryl and 3,5-diarylpyrazoles with a broad substitution pattern in moderate to excellent yield.
- Stephan, Marvin,Panther, Jesco,Wilbert, Fabio,Ozog, Pauline,Müller, Thomas J. J.
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p. 2086 - 2092
(2020/03/23)
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- One-pot regioselective synthesis of substituted pyrazoles and isoxazoles in PEG-400/water medium by Cu-free nano-Pd catalyzed sequential acyl Sonogashira coupling-intramolecular cyclization
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Catalyst efficacy of in situ generated Pd-nanoparticles (PdNPs) in the regioselective one-pot synthesis of 3,5-di & 3,4,5-trisubstituted pyrazoles and 3,5-disubstituted isoxazoles in environmentally benign PEG-400/H2O medium, which involves the sequential (i) Cu-free acyl-Sonogashira coupling (ASC) and (ii) intramolecular ynone-amine cyclization under PTC conditions was described. The results of controlled experiments support the operation of two sequential catalytic cycles (ASC/cyclization) and achievement of complementary/opposite regioselectivity via ynone-bound palladium in a one-pot approach. Moreover, the in situ PdNPs recovered after the first catalytic cycle of the one-pot reaction sequence have been reused again five times successively. Besides, prior to the above studies, the efficacy of some common Pd-N-heterocyclic carbene (Pd-NHC) complexes in catalyzing the same one-pot two-step reaction sequence (Cu-free ASC/cyclization) both in water and organic solvents was also optimized. In situ generation of PdNPs from above Pd-NHCs in water was also identified, but they are not reusable due to their large size distribution.
- Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Botla, Vinayak,Vadde, Ravinder,Jonnalagadda, Sreekantha Babu,Vasam, Chandra Sekhar
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p. 6471 - 6481
(2019/11/20)
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- Copper-Promoted Oxidative Intramolecular C–H Amination of Hydrazones to Synthesize 1H-Indazoles and 1H-Pyrazoles Using a Cleavable Directing Group
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A facile and efficient synthesis of 1H-indazoles and 1H-pyrazoles through a copper-promoted oxidative intramolecular C–H amination of hydrazones using a cleavable directing group was developed. This reaction is characterized by its mild conditions, operational simplicity, readily available reagents, and excellent yields. A tentative mechanism for Cu-mediated C–H oxidative amination was proposed.
- Zhang, Guofu,Fan, Qiankun,Zhao, Yiyong,Ding, Chengrong
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p. 5801 - 5806
(2019/08/02)
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- An Efficient Synthesis of Substituted Pyrazoles from One-Pot Reaction of Ketones, Aldehydes, and Hydrazine Monohydrochloride
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An efficient, one-pot and metal-free process for the preparation of 3,5-disubstituted and 3,4,5-trisubstituted pyrazoles on multi-gram scale was developed. One-pot condensation of ketones, aldehydes and hydrazine monohydrochloride readily formed pyrazoline intermediates under mild conditions. Oxidation of pyrazolines, in situ, employing bromine afforded a wide variety of pyrazoles. The methodology offers a fast, and often chromatography-free protocol for the synthesis of 3,4,5-substituted pyrazoles in good to excellent yields. Alternatively, a more benign oxidation protocol affords 3,5-disubstituted or 3,4,5-trisubstituted pyrazoles by simply heating pyrazolines in DMSO under oxygen.
- Lellek, Vit,Chen, Cheng-Yi,Yang, Wanggui,Liu, Jie,Ji, Xuebao,Faessler, Roger
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supporting information
p. 1071 - 1075
(2018/02/26)
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- The diaza-Nazarov cyclization involving a 2,3-diaza-pentadienyl cation for the synthesis of polysubstituted pyrazoles
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An unprecedented iodine-mediated diaza-Nazarov (DAN) type cyclization for the construction of substituted pyrazoles from easily available starting materials via an enamine-iminium ion intermediate is described. The oxidative cyclization worked under green conditions with remarkable regioselectivity. This one-pot, efficient and operationally simple three-component intramolecular regioselective DAN cyclization displayed a wide range of substrate scope. The dichotomy of reaction pathways has been explored with density functional theory in the gas phase and solution phase. Of the possible 1,5-, 1,6-, and 1,7-electrocyclizations, the DAN cyclization, i.e., the 1,5-pathway offers the lowest activation energy barrier supporting our experimental observations.
- Aegurla, Balakrishna,Peddinti, Rama Krishna
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p. 9643 - 9652
(2017/11/30)
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- A highly efficient heterogeneous palladium-catalyzed cascade three-component reaction of acid chlorides, terminal alkynes and hydrazines leading to pyrazoles
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In the presence of 0.5 mol% of 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized palladium(II) complex [MCM-41-2N-Pd(OAc)2] and 1.0 mol% of CuI, acid chlorides were coupled with terminal alkynes in Et3N at 50 °C to give α,β-unsaturated ynones, which were converted in situ into pyrazoles by the cycloaddition of hydrazines at room temperature with acetonitrile as cosolvent. The cascade reactions generated a variety of pyrazole derivatives in moderate to good yields, and this heterogeneous palladium catalyst exhibited higher catalytic activity than PdCl2(PPh3)2 and could be recovered and reused for at least 10 consecutive trials without any decreases in activity.
- Chen, Qiurong,Yao, Fang,Yin, Lin,Cai, Mingzhong
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p. 108 - 113
(2016/01/15)
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- One-Pot Coupling-Coupling-Cyclocondensation Synthesis of Fluorescent Pyrazoles
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Consecutive four-component coupling-coupling-cyclocondensation syntheses of pyrazoles and pyrimidines were developed by taking advantage of the provisional, sequentially Pd-catalyzed one-pot generation of alkynones from aryl iodides, ethynylmagnesium bromide, and acid chlorides. This one-pot methodology allows the concise, diversity-oriented generation of a set of donor-, acceptor-, and donor-acceptor-substituted pyrazoles, which are interesting fluorophores. Most distinctly, donor-acceptor pyrazoles display remarkably red-shifted emission maxima and pronounced positive solvochromicity, spanning an overall range from 363 nm (cyclohexane) to 595 nm (acetonitrile). DFT and TD-DFT calculations elucidate the electronic structure and the photophysical behavior. Upon photonic excitation, considerable charge-transfer character becomes apparent, which rationalizes the origin of huge Stokes shifts and solvochromic behavior.
- G?tzinger, Alissa C.,The?eling, Florian A.,Hoppe, Corinna,Müller, Thomas J. J.
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p. 10328 - 10338
(2016/11/17)
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- Iron(III) phthalocyanine chloride-catalyzed oxidation-aromatization of α,β-unsaturated ketones with hydrazine hydrate: Synthesis of 3,5-disubstituted 1H-pyrazoles
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We have developed an iron(III) phthalocyanine chloride-catalyzed oxidation-aromatization of α,β-unsaturated ketones with hydrazine hydrate. Various 3,5-disubstituted 1H-pyrazoles were obtained in good to excellent yields. This method offers several advantages, including room-temperature conditions, short reaction time, high yields, simple work-up procedure, and use of air as an oxidant. The catalyst can be recovered and reused five times without loss of activity.
- Zhao, Junlong,Qiu, Jun,Gou, Xiaofeng,Hua, Chengwen,Chen, Bang
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p. 571 - 578
(2016/04/20)
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- Phosphine- and copper-free palladium catalyzed one-pot four-component carbonylation reaction for the synthesis of isoxazoles and pyrazoles
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The palladium catalyzed one-pot synthesis of isoxazoles and pyrazoles from aryl iodides, terminal alkynes, chromium hexacarbonyl and hydroxylamine hydrochloride or aqueous hydrazine solution is described. The Sonogashira carbonylative coupling intermediate was trapped in situ by hydroxylamine hydrochloride or aqueous hydrazine to deliver isoxazoles or pyrazoles, respectively, in high yields. This efficient method proceeds at atmospheric pressure and moderate temperature and does not require the use of copper, phosphine ligands or gaseous carbon monoxide.
- Iranpoor, Nasser,Firouzabadi, Habib,Etemadi-Davan, Elham
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supporting information
p. 837 - 840
(2016/02/05)
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- Sulphur promoted C(sp3)-C(sp2) cross dehydrogenative cyclisation of acetophenone hydrazones with aldehydes: Efficient synthesis of 3,4,5-trisubstituted 1H-pyrazoles
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A novel strategy for the cross dehydrogenative coupling (CDC) of acetophenone hydrazones and aldehydes has been developed for the synthesis of highly substituted pyrazoles. This work, for the first time, uses elemental sulfur as a promoter as well as a hydrogen acceptor in effecting the Csp3-Csp2 bond formation via C-H activation. This journal is
- Vanjari, Rajeshwer,Guntreddi, Tirumaleswararao,Kumar, Saurabh,Singh, Krishna Nand
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p. 366 - 369
(2015/01/09)
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- Synthesis of 3,5-disubstituted-1H-pyrazoles from acid chlorides, alkynes, and hydrazine in the presence of silica-supported-zinc bromide
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An efficient one-pot palladium- And copper-free procedure has been developed for a convenient synthesis of 3,5-disubstituted-1H-pyrazoles from various acid chlorides, terminal alkynes and hydrazine by a coupling reaction and cyclocondensation sequence. Acid chlorides react with terminal alkynes in the presence of silica-supported-zinc bromide to give α,β-unsaturated ynones, and in situ conversion into pyrazoles by the hydrazine cyclocondensation.
- Keivanloo, Ali,Bakherad, Mohammad,Samangooei, Shahrzad
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p. 484 - 486
(2015/11/03)
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- One-pot synthesis of 3,5-diphenyl-1h-pyrazoles from chalcones and hydrazine under mechanochemical ball milling
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A highly efficient and environmentally friendly method has been developed for facile synthesis of 3,5-diphenyl-1H-pyrazoles under mechanochemical ball-milling conditions. The advantages of short reaction time, high efficiency, no separation of in situ generated intermediate, using cheap sodium persulfate as the oxidant, together with very simple work-up procedure, make this one-pot and solvent-free protocol a green and powerful alternative to traditional methods for the synthesis of these kinds of compounds.
- Zhang, Ze,Tan, Ya-Jun,Wang, Chun-Shan,Wu, Hao-Hao
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p. 103 - 112
(2014/02/14)
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- Preparation of 3,5-disubstituted pyrazoles and isoxazoles from terminal alkynes, aldehydes, hydrazines, and hydroxylamine
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The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3,5-disubstituted pyrazoles from terminal alkynes, aldehydes, molecular iodine, and hydrazines, and 3,5-disubstituted isoxazoles from terminal alkynes, aldehydes, molecular iodine, and hydroxylamine.
- Harigae, Ryo,Moriyama, Katsuhiko,Togo, Hideo
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p. 2049 - 2058
(2014/04/03)
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- Synthesis of pyrazoles through copper-catalyzed three-component coupling of aldehydes, alkynes, and p-toluenesulfonylhydrazide
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A convenient one-pot synthesis of 3,5-disubstitued 1H-pyrazoles through copper-catalyzed three-component coupling of aldehydes, alkynes, and p-toluenesulfonylhydrazide has been developed. This method provides a flexible and rapid route to 3,5-disubstituted 1H-pyrazoles.
- Wu, Feng,Hao, Lu,Zhan, Zhuang-Ping
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p. 657 - 663
(2013/04/10)
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- Design, synthesis and structure-activity relationships of 3,5-diaryl-1H-pyrazoles as inhibitors of arylamine N-acetyltransferase
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The synthesis and inhibitory potencies of a novel series of 3,5-diaryl-1H-pyrazoles as specific inhibitors of prokaryotic arylamine N-acetyltransferase enzymes is described. The series is based on hit compound 1 3,5-diaryl-1H-pyrazole identified from a high-throughout screen that has been carried out previously and found to inhibit the growth of Mycobacterium tuberculosis.
- Fullam, Elizabeth,Talbot, James,Abuhammed, Areej,Westwood, Isaac,Davies, Stephen G.,Russell, Angela J.,Sim, Edith
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supporting information
p. 2759 - 2764
(2013/06/27)
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- Copper on iron promoted one-pot synthesis of β-aminoenones and 3,5-disubstituted pyrazoles
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The reaction of hydroximoyl chlorides with acetylenes in the presence of a copper on iron bimetallic system leads to β-aminoenones via reductive ring opening of isoxazole intermediates. The valuable β-aminoenone building blocks can be isolated or transformed into pyrazoles with the addition of hydrazine in a straightforward one-pot procedure.
- Kovács, Szabolcs,Novák, Zoltán
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p. 8987 - 8993
(2013/09/24)
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- Silica gel-supported palladium catalyst for the acyl sonogashira reaction
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The acyl Sonogashira reaction between acyl chlorides and terminal alkynes is one of the most useful method for the preparation of ynones which are important intermediates to prepare versatile pharmaceutically and biologically active heterocyclic compounds such as pyrroles, pyrazoles, furans, furanones, isoxazoles, pyrimidines, quinolines, indolizidinones. 3- Mercaptopropyltrimethoxysilane and palladium supported silica has received considerable attention in organic synthesis for its availability, low cost, excellent heterogeneous nature, and ease of handling. It was effectively used in various organic syntheses. Despite various coupling reactions and exceptional heterogeneity, till now thiol containing palladium silica catalyst for ynones synthesis has not been reported. Due to the higher uptake capacity of palladium acetate in mercaptopropyl silica gel, 0.40 mmol/gm palladium loading was achieved easily. Inductively coupled plasma (ICP) analysis also confirmed the palladium content.
- Hossain, Shahin,Park, Ji-Hoon,Park, Min-Kyu,Jin, Myung-Jong
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p. 411 - 415
(2013/07/26)
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- Facile one-pot synthesis of 3,5-disubstituted 1 h -pyrazoles from propargylic alcohols via propargyl hydrazides
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A new and efficient metal-free, two-component, one-pot approach to a variety of 3,5-disubstituted 1H-pyrazoles has been developed from propargylic alcohols. This transformation proceeds via an acid-catalyzed propargylation of N,N-diprotected hydrazines followed by base-mediated 5-endo-dig cyclization leading to 3,5-disubstituted 1H-pyrazoles in good overall yields. Georg Thieme Verlag Stuttgart. New York.
- Raji Reddy, Chada,Vijaykumar, Jonnalagadda,Grée, René
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p. 830 - 836
(2013/04/23)
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- Chemoselective synthesis of substituted pyrazoles through AgOTf-catalyzed cascade propargylic substitution-cyclization-aromatization
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A cascade AgOTf-catalyzed chemoselective approach to 3,5/1,3-disubstitued pyrazoles from propargylic alcohols and para-tolylsulfonohydrazide has been developed. Good chemoselectivity is observed depending on the different substituents in the alkyne moiety of the propargylic alcohols, generating two different kinds of products through different aromatization mechanisms. The pyrazolo[5,1-a]isoquinoline skeleton can also be effectively constructed by this method through a cascade bicyclization process.
- Xu, Su-Xia,Hao, Lu,Wang, Tao,Ding, Zong-Cang,Zhan, Zhuang-Ping
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supporting information
p. 294 - 298
(2013/02/23)
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- An efficient one-pot synthesis of 3,5-disubstituted 1H-pyrazoles
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An efficient, general, one-pot, three-component procedure for the preparation of 3,5-disubstituted 1H-pyrazoles via condensation of substituted aromatic aldehydes, tosylhydrazine and terminal alkynes in toluene is reported. The reaction tolerates a variety of functional groups and sterically hindered substrates to afford the desired pyrazoles in yields of 67-91%.
- Wu, Lei-Lei,Ge, Yi-Cen,He, Ting,Zhang, Lei,Fu, Xing-Li,Fu, Hai-Yan,Chen, Hua,Li, Rui-Xiang
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p. 1577 - 1583
(2012/06/29)
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- A complementary approach to 3,5-substituted pyrazoles with tosylhydrazones and terminal alkynes mediated by TfOH
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A complementary method for the preparation of 3,5-substituted pyrazoles in moderate to high yields has been explored via TfOH-induced addition of tosylhydrazones to the terminal alkynes. This acid-induced addition procedure might be an operationally safe alternative compared to typical 1,3-dipolar cycloaddition as there is no involvement of diazo compounds.
- Liu, Ping,Xu, Qian-Qian,Dong, Chao,Lei, Xinsheng,Lin, Guo-Qiang
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p. 2087 - 2092
(2012/11/07)
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- One-pot four-component reaction for the generation of pyrazoles and pyrimidines
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The palladium-catalysed four-component coupling of a halide, terminal alkyne, molybdenum hexacarbonyl and either a hydrazine or amidine has been shown to be an efficient method for the construction of highly substituted pyrazoles and pyrimidines, respectively, in a one-pot process. Georg Thieme Verlag Stuttgart.
- Stonehouse, Jeffrey P.,Chekmarev, Dmitriy S.,Ivanova, Natalya V.,Lang, Stuart,Pairaudeau, Garry,Smith, Neal,Stocks, Michael J.,Sviridov, Sergey I.,Utkina, Lyubov M.
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p. 100 - 104
(2008/09/21)
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- Aryl azoles with neuroprotective activity-Parallel synthesis and attempts at target identification
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A parallel synthesis of aryl azoles with neuroprotective activity is described. All compounds obtained were evaluated in an in vitro assay using a NMDA toxicity paradigm showing a neuroprotective activity between 15% and 40%. The potential biological target of the active compounds was investigated by extensive literature searches based around similar scaffolds with reported neuroprotective activity. The most interesting molecules active in the NMDA toxicity assay (3a and 2g) showed moderate but significant activity in the inhibition of the Site 2 Sodium Channel binding assay at 10 μM. To confirm our hypothesis compounds 3a, c, f and 2g were tested in the Veratridine assay which is one of the excitotoxicity assays of revelance to NaV channels. The compounds tested showed an activity between 40% and 70%. The identification of neuroprotective small molecules and the identification of NaV channels as the potential site of action were the most important goals of this work.
- Cocconcelli, Giuseppe,Diodato, Enrica,Caricasole, Andrea,Gaviraghi, Giovanni,Genesio, Eva,Ghiron, Chiara,Magnoni, Letizia,Pecchioli, Elena,Plazzi, Pier Vincenzo,Terstappen, Georg C.
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p. 2043 - 2052
(2008/09/21)
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- A facile and convenient approach to the synthesis of 3,5-diaryl-1H- pyrazoles
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A simple and convenient one-pot synthesis route is described for the synthesis of 3,5-diaryl-1H-pyrazoles in short reaction times from the reaction of α-epoxyketones with semicarbazide hydrochloride under mild conditions.
- Nikpour, Farzad,Beigvand, Mahdi
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experimental part
p. 821 - 824
(2009/09/24)
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- Facile preparation of allyl amines and pyrazoles by hydrazinolysis of 2-ketoaziridines
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Allyl amines and pyrazoles can be obtained by hydrazinolysis of 2-ketoaziridines. A variety of aziridines, including N-unprotected, N-substituted, as well as bicyclic enamine and aminal type, can be transformed into diversely substituted linear or cyclic products. The hydrazinolysis of homochiral aziridines proceeds without racemization.
- Chen, Gang,Sasaki, Mikio,Yudin, Andrei K.
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p. 255 - 259
(2007/10/03)
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- A novel synthesis of 5-aryl-3-phenylpyrazole from 2-aryl-3-benzoyl-1,1- cyclopropanedicarbonitrile and hydrazine
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A new process for synthesis of 5-aryl-3-phenylpyrazole is achieved. The regioselective ring-opening reaction of 2-aryl-3-benzoyl-1,1- cyclopropanedicarbonitrile with hydrazine plays a crucial role in the described process.
- Ren, Zhongjiao,Cao, Weiguo,Chen, Jie,Wang, Yu,Ding, Weiyu
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p. 495 - 497
(2007/10/03)
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- One-pot construction of pyrazoles and isoxazoles with palladium-catalyzed four-component coupling
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(Chemical Equation Presented) Four-component coupling of a terminal alkyne, hydrazine (hydroxylamine), carbon monoxide, and an aryl iodide furnishes pyrazole or isoxazole derivatives in the presence of a palladium catalyst. The reaction proceeds at room temperature and an ambient pressure of carbon monoxide in an aqueous solvent system.
- Mohamed Ahmed, Mohamed S.,Kobayashi, Kei,Mori, Atsunori
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p. 4487 - 4489
(2007/10/03)
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- A novel one-pot method for the preparation of pyrazoles by 1,3-dipolar cycloadditions of diazo compounds generated in situ
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A convenient one-pot procedure for the preparation of pyrazoles by 1,3-dipolar cycloaddition of diazo compounds generated in situ has been developed. Diazo compounds derived from aldehydes were reacted with terminal alkynes to furnish regioselectively 3,5-disubstituted pyrazoles. Furthermore, the reaction of N-vinylimidazole and diazo compounds derived from aldehydes gave exclusively 3-substituted pyrazoles in a one-pot process.
- Aggarwal, Varinder K.,De Vicente, Javier,Bonnert, Roger V.
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p. 5381 - 5383
(2007/10/03)
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- Isothiazoles. Part 3. Cycloadditions of Diazoalkanes to 3-Dialkylaminoisothiazole 1,1-Dioxides. Competitive Ring Cleavage in 3a,4-Dihydro-6aH-pyrazoloisothiazole 1,1-Dioxides: Formation of 2-Thia-3-azabicyclohex-3-ene 2,2-Dioxides and/or Pyrazoles
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3-Dialkylaminoisothiazole 1,1-dioxides 1 readily undergo cycloadditions with diazoalkanes 2.The reaction is characterized by high site- and regio-selectivity.Cycloadducts 3 and 4 were found to undergo straightforward thermolysis reactions at elevated temperature through two different paths characterized respectively by loss of nitrogen or sulfur dioxide and diethylcyanamide.The different transformations affording pyrazoles 6 and derivatives of the new heterocycle 2-thia-3-azabicyclohex-3-ene 2,2-dioxide 5 are discussed.
- Clerici, Francesca,Ferrario, Tiziano,Gelmi, Maria Luisa,Marelli, Roberto
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p. 2533 - 2536
(2007/10/02)
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- Stereochemistry of Base-catalysed Addition of Methyl Mercaptoacetate to Acetylenic Ketones and Esters. Effects of Activating Groups and Solvents
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Piperidine-catalysed addition of methyl mercaptoacetate to benzoyl- and p-chlorobenzoyl-phenylacetylenes in ethanol gave the corresponding (Z)-1-aryl-3-(methoxycarbonylmethylthio)-3-phenyl-2-propen-1-one.However, p-anisoylphenylacetylene gave a mixture of (Z)- and (E)-3-(methoxycarbonylmethylthio)-1-(p-methoxyphenyl)-3-phenyl-2-propen-1-ones in the ratio of 4:1.This ratio was completely inverted when the latter addition was carried out in dry benzene.Rationalisation of these results is presented which depends on the effect of activating groups and solvents on thestereochemistry of addition.Piperidine-catalysed addition of methyl mercaptoacetate to methyl phenylpropiolate in ethanol gave methyl (Z)-3-(methoxycarbonylmethylthio)cinnamate.Hydrazine hydrate converted some of the above mono-adducts into some pyrazole derivatives.
- Basyouni, Mohamed Nabih,Omar, Mohamed Tawfik,Ghali, Edwar Amin
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p. 1739 - 1742
(2007/10/02)
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