- A green protocol for catalyst-free syntheses of pyrazole in glycerol-water solution
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An efficient green protocol for preparing pyrazole derivatives using glycerol and water as a mixture solvent is described. The advantages of the present method lie in using economic and environmentally benign solvent, no use of catalyst, mild reaction conditions and good yields.
- Min, Zhen-Li,Zhang, Qian,Hong, Xing,Cao, Xiao-Lu,Hu, Xia-Min
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- Synthesis of Unsymmetrical 2,6-Diarylanilines by Palladium-Catalyzed C-H Bond Functionalization Methodology
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3,5-Dimethylpyrazole was employed as a monodentate directing group for palladium-catalyzed ortho-sp2 C-H arylation with aryl iodides. The reaction shows good functional group tolerance and outstanding selectivity for mono-ortho-arylation. Ozonolysis of ortho-arylated arylpyrazoles gave acylated biphenylamines that were further arylated to afford unsymmetrically substituted 2,6-diarylacetanilides.
- Kwak, Se Hun,Gulia, Nurbey,Daugulis, Olafs
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- Translating high-temperature microwave chemistry to scalable continuous flow processes
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A comparison between batch microwave and conventionally heated continuous flow scale-up protocols for three selected model reactions is presented. Using high-temperature/-pressure conditions as process intensification principles, reaction times for all three transformations were reduced to a few seconds or minutes at temperatures ranging from.
- Damm, Markus,Glasnov, Toma N.,Kappe, C. Oliver
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- Synthesis, characterization and antibacterial applications of pyrazolyl-sulfonamides and their palladium complexes
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A series of pyrazolyl sulfonamide compounds were prepared by a multi-step procedure involving preparation of phenyl pyrazolyl compounds (C1, C2) and their chlorosulfonated derivatives (C3-C5), which were then converted to sulfonamides (L1-L6). Complexes of L1-L6 with palladium(ii) show the standard trans square-planar coordination environment for the six complexes (1-6). All products were prepared in moderate to high yield (61-81%). All compounds were successfully characterized by NMR spectroscopy, IR spectroscopy, mass spectrometry and in one case single X-ray crystallography. Conversion of C1 and C2 to C3-C5 is governed by steric hindrance on the pyrazolyl group as sulfonation of the phenyl only is observed for tBu groups (C4), whereas for Me groups sulfonation of the pyrazolyl is observed C3 as well as phenyl ring for C5. Antimicrobial screening was carried out on the compounds using the agar-well diffusion method at varying concentrations of (62.5, 125, 250, 500 and 1000 μg mL-1) on ten (10) bacteria strains. The zone of inhibition for all the compounds are within the ranges of 9.5 mm to 25 mm compared to the control antibiotic, gentamicin that was between 16.5 mm to 36 mm. The compounds L1-L6 generally showed mild to strong antibacterial activity in the zones of inhibition against most Gram negative bacteria strains tested, but no activity against Gram positive bacteria strains Staphylococcus aureus and Enterococcus faecalis, except L4 which showed activity towards Staphylococcus. The palladium(ii) complexes generally showed improved activities for all the bacteria strains studied with 4 exhibiting the most potent in vitro anti-bacterial activity with MICs of 1.046 μg mL-1 and 0.237 μg mL-1 against Staphylococcus epidermidis and Proteus mirabilis respectively. Theoretical Log P calculation show values between 3.06 and 5.95 for the ligands and between 6.67 and 12.36 for complexes. Suggesting high affinity of these compounds to the lipophilic medium. However, the experimental Log P value gave a different trend, which shows that compounds with sulfonation only on the phenyl ring (L3 (-0.83), L4 (-0.53), 3 (-0.96) and 4 (-0.72)) have high affinity for the hydrophilic medium. This journal is
- Amoah, Cephas,Obuah, Collins,Ainooson, Michael Kojo,Adokoh, Christian Kwaku,Muller, Alfred
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- Highly reusable support-free copper(II) complex of para-hydroxy-substituted salen: Novel, efficient and versatile catalyst for C─N bond forming reactions
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An air-stable, highly active and versatile method for C─N bond forming reactions is reported. Under mild conditions using a highly reusable support-free Cu(II)–salen complex, structurally diverse N-aryl-substituted compounds were obtained via direct C─N bond forming reaction of HN-heterocycles with aryl iodides or three-component C─N bond forming reaction of 2-bromobenzaldehyde, aniline derivatives and sodium azide in good to excellent yields. C─N bond forming reaction for benzimidazole derivatives was also performed in the presence of the catalyst under ambient conditions. A series of hybrid benzimidazoles bearing morpholine, tetrazole and quinoxaline backbones were produced using this method. All reactions were performed in short times under air. The Cu(II) catalyst could be reused up to eight times in the direct cross-coupling reaction of 9H–carbazole with iodobenzene without any decrease in its catalytic activity.
- Sharghi, Hashem,Aberi, Mahdi,Shiri, Pezhman
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- NSC 18725, a Pyrazole Derivative Inhibits Growth of Intracellular Mycobacterium tuberculosis by Induction of Autophagy
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The increasing incident rates of drug-resistant tuberculosis (DR-TB) is a global health concern and has been further complicated by the emergence of extensive and total drug-resistant strains. Identification of new chemical entities which are compatible with first-line TB drugs, possess activity against DR-, and metabolically less active bacteria is required to tackle this epidemic. Here, we have performed phenotypic screening of a small molecule library against Mycobacterium bovis BCG and identified 24 scaffolds that exhibited MIC99 values of at least 2.5 μM. The most potent small molecule identified in our study was a nitroso containing pyrazole derivative, NSC 18725. We observed a significant reduction in viable bacilli load of starved Mycobacterium tuberculosis upon exposure to NSC 18725. The action of NSC 18725 was “synergistic” with isoniazid (INH) and “additive” with other drugs in our checkerboard assays. Structure-activity relationship (SAR) studies of the parent compound revealed that pyrazole derivatives without a functional group at fourth position lacked anti-mycobacterial activity in vitro. The derivative with para-chlorophenyl substitution at the first position of the pyrazole ring was the most active scaffold. We also demonstrate that NSC 18725 is able to induce autophagy in differentiated THP-1 macrophages. The induction of autophagy by NSC 18725 is the major mechanism for the killing of intracellular slow and fast-growing mycobacteria. Taken together, these observations support the identification of NSC 18725 as an antimycobacterial compound, which synergizes with INH, is active against non-replicative mycobacteria and induces autophagy in macrophages.
- Arora, Garima,Behura, Assirbad,Dhiman, Rohan,Gagandeep, Garima,Gosain, Tannu Priya,Kandi, Shamseer Kulangara,Kidwai, Saqib,Rawat, Diwan S.,Shaliwal, Ravi P.,Singh, Padam,Singh, Ramandeep
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- Synthesis of 1,3,5-Trisubstituted Pyrazoles and Hydrazones Using Fe3O4?CeO2 Nanocomposite as an Efficient Heterogeneous Nanocatalyst
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Abstract: Pyrazoles and hydrazones, as two significant kinds of potentially bioactivecompounds, were produced with good to excellent yields by condensation ofβ-dicarbonyl compounds with hydrazines in aqueous media in the presence ofFe3O4?CeO2nanocomposite as an efficient heterogeneous nanocatalyst. The magneticnanocatalyst can readily be separated using an external magnet and reused atleast six times without significant loss in activity. The products werecharacterized by IR and 1H and13C NMR spectra.
- Hassani, H.,Jahani, Z.
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- Magnetic nanoparticle-supported glutathione: A conceptually sustainable organocatalyst
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A conceptually novel nanoparticle-supported and magnetically recoverable organocatalyst has been developed, which is readily prepared from inexpensive starting materials in a truly sustainable manner; which catalyzes the Paal-Knorr reaction with high yield in pure aqueous medium that avoids the use of toxic organic solvents, even in the workup step.
- Polshettiwar, Vivek,Baruwati, Babita,Varma, Rajender S.
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- Interconversion of nicotine enantiomers during heating and implications for smoke from combustible cigarettes, heated tobacco products, and electronic cigarettes
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Physiological properties of (R)-nicotine have differences compared with (S)-nicotine, and the subject of (S)- and (R)-nicotine ratio in smoking or vaping related items is of considerable interest. A Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS) method for the analysis of (S)- and (R)-nicotine has been developed and applied to samples of nicotine from different sources, nicotine pyrolyzates, several types of tobacco, smoke from combustible cigarettes, smoke from heated tobacco products, e-liquids, and particulate matter obtained from e-cigarettes aerosol. The separation was achieved on a Chiracel OJ-3 column, 250 × 4.6 mm with 3-μm particles using a nonaqueous mobile phase. The detection was performed using atmospheric pressure chemical ionization (APCI) in positive mode. The only transition measured for the analysis of nicotine was 163.1 → 84.0. The method has been summarily validated. For the analysis, the samples of tobacco and smoke from combustible cigarettes were subject to a cleanup procedure using solid phase extraction (SPE). It was demonstrated that nicotine upon heating above 450°C for several minutes starts decomposing, and some formation of (R)-enantiomer from a sample of 99% (S)-nicotine is observed. An analogous process takes place when a 99% (R)-nicotine is heated and forms low levels of (S)-nicotine. This interconversion has the effect of slightly increasing the content of (R)-nicotine in smoke compared with the level in tobacco for combustible cigarettes and for heated tobacco products. The (S)/(R) ratio of nicotine enantiomers in e-liquids was identical with the ratio for the particulate phase of aerosols generated by e-cigarette vaping.
- Moldoveanu, Serban C.
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p. 667 - 677
(2022/02/02)
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- Predicting the catalytic activity of azolium-based halogen bond donors: an experimentally-verified theoretical study
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This report demonstrates the successful application of electrostatic surface potential distribution analysis for evaluating the relative catalytic activity of a series of azolium-based halogen bond donors. A strong correlation (R2> 0.97) was observed between the positive electrostatic potential of the σ-hole on the halogen atom and the Gibbs free energy of activation of the model reactions (i.e., halogen abstraction and carbonyl activation). The predictive ability of the applied approach was confirmed experimentally. It was also determined that the catalytic activity of azolium-based halogen bond donors was generally governed by the structure of the azolium cycle, whereas the substituents on the heterocycle had a limited impact on the activity. Ultimately, this study highlighted four of the most promising azolium halogen bond donors, which are expected to exhibit high catalytic activity.
- Bolotin, Dmitrii S.,Il'in, Mikhail V.,Novikov, Alexander S.,Suslonov, Vitalii V.,Sysoeva, Alexandra A.
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p. 7611 - 7620
(2021/09/22)
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- Cross-Coupling between Hydrazine and Aryl Halides with Hydroxide Base at Low Loadings of Palladium by Rate-Determining Deprotonation of Bound Hydrazine
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Reported here is the Pd-catalyzed C–N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as low as 100 ppm of Pd and KOH as base. Mechanistic studies revealed two catalyst resting states: an arylpalladium(II) hydroxide and arylpalladium(II) chloride. These compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matched that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process occurs by rate-limiting deprotonation of a hydrazine-bound arylpalladium(II) chloride complex to give an arylpalladium(II) hydrazido complex.
- Borate, Kailaskumar,Choi, Kyoungmin,Goetz, Roland,Hartwig, John F.,Shinde, Harish,Wang, Justin Y.,Zuend, Stephan J.
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supporting information
p. 399 - 408
(2020/10/29)
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- Visible-light enabled C4-thiocyanation of pyrazoles by graphite-phase carbon nitride (g-C3N4)
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Thiocyanation is an important and effective way to form C[sbnd]S bonds in organic synthetic methodology. Especially, thiocyanation of pyrazole attracts the attention of many researchers because sulfur-containing compounds are widely applied in many crucial fields such as organic materials, agrochemistry, nanotechnology, etc. Herein, we described A rapid metal- and additive-free method for C(sp2)-H thiocyanation of pyrazoles under visible light at room temperature by using a sustainable catalyst of graphite-phase carbon nitride (g-C3N4) and a thiocyanating agent of ammonium thiocyanate. The method presents many advantages, such as usage of eco-friendly photoredox catalyst, a wide range of substrates and a good yield of products, etc.
- Pan, Junyi,Liu, Cheng,Wang, Jianqiang,Dai, Yunqiao,Wang, Shengyu,Guo, Cheng
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supporting information
(2021/07/14)
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- Direct Preparation of N-Substituted Pyrazoles from Primary Aliphatic or Aromatic Amines
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Despite a large number of synthesis procedures for pyrazoles known today, those directly employing primary amines as substrates are rare. Herein, we report an original method for the preparation of N-alkyl and N-aryl pyrazoles from primary aliphatic or aromatic amines as a limiting reagent of the reaction. The protocol utilizes no inorganic reagents and requires a short reaction time, mild conditions, and the use of structurally simple and commercially available starting reagents. During this study, pyrazoles containing a wide variety of N-substituents were obtained using the same procedure for both aliphatic and aromatic amines.
- Gulia, Nurbey,Ma?ecki, Marcin,Szafert, S?awomir
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p. 9353 - 9359
(2021/07/26)
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- Synthesis of quinoxaline, benzimidazole and pyrazole derivatives under the catalytic influence?of biosurfactant-stabilized iron nanoparticles in water
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Abstract: We have reported the synthesis, characterization, and catalytic applications of amorphous iron nanoparticles (FeNPs) using aqueous leaves extract of renewable natural resource Boswellia serrata plant. Synthesized FeNPs were stabilized in situ by the addition of aqueous pod extracts of Acacia concinna as a biosurfactant (pH 3.11). The structural investigation of biosynthesized nanoparticles was performed using UV–visible spectroscopy, X-ray diffraction analysis, selected area electron diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and BET analysis. The FeNPs were amorphous in nature with average particle size ~ 19?nm and successfully employed as heterogeneous catalyst for the synthesis of quinoxaline, benzimidazole, and pyrazole derivatives in aqueous medium at ambient conditions. The FeNPs could be recycled up to five times with modest change in the catalytic activity. Graphic abstract: [Figure not available: see fulltext.].
- Arde, Satyanarayan M.,Patil, Audumbar D.,Mane, Ananda H.,Salokhe, Prabha R.,Salunkhe, Rajashri S.
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p. 5069 - 5086
(2020/09/02)
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- PROCESS FOR THE SYNTHESIS OF ARYL HYDRAZINES
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The invention relates to a process for the synthesis of aryl hydrazinesof formula I or a salt thereof, which process comprises subjecting an arene of formula II to a coupling reaction with hydrazine or a derivative thereof, wherein the coupling reaction is conducted in the presence of a catalyst comprising palladium and a diphosphine ligand, wherein the phosphorus atoms are connected through two, three, four, or five atoms selected from car- bon, nitrogen, oxygen or iron, and in which the non-connecting phosphorus substituents are C1- C 10-alkyl or C3-C10-cycloalkyl, wherein the amount of Pd used is up to 0.5 mol-% relative to the amount of arene of formula II; and a base.
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Page/Page column 22; 25
(2020/06/01)
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- Improving the Potency of N-Aryl-2,5-dimethylpyrroles against Multidrug-Resistant and Intracellular Mycobacteria
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A series of N-phenyl-2,5-dimethylpyrrole derivatives, designed as hybrids of the antitubercular agents BM212 and SQ109, have been synthesized and evaluated against susceptible and drug-resistant mycobacteria strains. Compound 5d, bearing a cyclohexylmethylene side chain, showed high potency against M. tuberculosis including MDR-TB strains at submicromolar concentrations. The new compound shows bacteriostatic activity and low toxicity and proved to be effective against intracellular mycobacteria too, showing an activity profile similar to isoniazid.
- Touitou, Meir,Manetti, Fabrizio,Ribeiro, Camila Maringolo,Pavan, Fernando Rogerio,Scalacci, Nicolò,Zrebna, Katarina,Begum, Neelu,Semenya, Dorothy,Gupta, Antima,Bhakta, Sanjib,Mchugh, Timothy D.,Senderowitz, Hanoch,Kyriazi, Melina,Castagnolo, Daniele
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supporting information
p. 638 - 644
(2020/01/11)
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- Oxone-DMSO Triggered Methylene Insertion and C(sp2)-C(sp3)-H-C(sp2) Bond Formation to Access Functional Bis-Heterocycles
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Metal-free insertion of a methylene group was achieved for the construction of a new C(sp2)-C(sp3)-H-C(sp2) bond in order to prepare novel bis-heterocyclic scaffolds. The complete mechanistic investigations included experimental study and DFT calculations, and various symmetric and unsymmetric bis-pyrazoles as well as other pyrazole-based bis-heterocyclic molecules were prepared in moderate to high yields. Further modification of the bridged methylene group in the unsymmetric pyrazoles generated a chiral center to extend the scope of this method.
- Bharatam, Prasad V.,Dubey, Gurudutt,Hussain, Yaseen,Kour, Jaspreet,Sahoo, Subash C.,Sawant, Sanghapal D.,Venkateswarlu, Vunnam,Verma, Praveen K.
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supporting information
p. 4951 - 4962
(2020/05/08)
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- 1-Aryl-3,5-dimethylpyrazolium based tunable protic ionic liquids (TPILs)
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A series of new 1-aryl-3,5-dimethylpyrazolium based tunable protic ionic liquids/salts ([PhRHpz][X], R: –H, –Cl, –Br, –CH3, –OCH3, X: chloride [Cl?] and tetrafluoroborate [BF4 ?]) have been synthesized through acid-base neutralization reactions between 1-aryl-3,5-dimethyl-1H-pyrazoles and the corresponding inorganic acids. The chemical structure of the salts was confirmed by FTIR, 1H NMR, 13C NMR, elemental analysis, and 19F NMR (3a-3e) and the crystal structure of the two salts (2a and 3d) was also elucidated by X-ray analysis of single crystals. Melting points and thermal decomposition temperatures of TPILs (2e and 3b) were determined. The geometries of the cations, anions and ionic salts were optimized, and their molecular electrostatic potentials (MEPs) were assessed by using density functional theory methods (B3LYP and M06-2X). The electrochemical window of the salts was determined both experimentally and theoretically. The correlation coefficient values were also calculated by using theoretical and experimental EW values of the salts.
- ?zdemir, Melek Canbulat,?zgün, Beytiye,Aktan, Ebru
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p. 564 - 572
(2019/01/05)
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- Transition metal containing ionic liquid-assisted one-pot synthesis of pyrazoles at room temperature
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Abstract: The feasible and one of the green ways to synthesize organic compounds especially pyrazole and its derivatives are systematically presented. The one-pot synthesis of pyrazole was achieved by condensation of various hydrazines and 1,3-diketone derivatives at room temperature using transition metal-based ionic liquids. Herein, the unique combination of Fe(III) with ionic liquid is explored and utilized as an efficient homogeneous catalyst for the synthesis of pyrazole and its derivatives. The homogenous catalyst thus synthesised was re-used up to the fourth cycle (with 90%, 88%, 84%, 78% yields respectively). Graphic abstract: Pyrazoles are synthesized in the presence of transition metal-based ionic liquids at room temperature. From the green chemistry perspective, ionic liquids are considered as green solvents which have gained remarkable attention because of its non-toxic, non-corrosive and non-flammable nature while the presence of transition metal as a part of counter anion gives it more catalytic activity. [Figure not available: see fulltext.].
- Konwar, Manashjyoti,Elnagdy, Hanan M F,Gehlot, Praveen Singh,Khupse, Nageshwar D,Kumar, Arvind,Sarma, Diganta
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- Cu1.5PMo12O40-catalyzed condensation cyclization for the synthesis of substituted pyrazoles
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A convenient and direct approach has been developed for the preparation of pyrazole derivatives by the condensation cyclization of hydrazines/hydrazide and 1,3-diketones in the presence of Cu1.5PMo12O40 (0.33?mol%) under mild conditions (r.t.-60?°C, 10–30?min). Notably, the reaction was found to be scalable as 99% yield was obtained when the reaction was performed at a 5-mmol scale. This solvent-free and halogen-free catalytic system represents an effective economic and environmentally friendly method for the construction of pyrazoles.
- Yang, Guo-Ping,He, Xing,Yu, Bing,Hu, Chang-Wen
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- Application and developing of iron-doped multi-walled carbon nanotubes (Fe/MWCNTs) as an efficient and reusable heterogeneous nanocatalyst in the synthesis of heterocyclic compounds
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Iron-doped multi-walled carbon nanotubes (Fe/MWCNTs) is an efficient, ecofriendly and reusable heterogeneous nanocatalyst for the one-pot synthesis of heterocyclic compounds including bis-spiro piperidines, piperidines, dihydro-2-oxopyrroles, pyrazoles and diazepines at room temperature with good to excellent yields. The heterogeneous nanocatalyst was fully characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP) and FT-IR analysis. Also, the structures of all prepared compounds were characterized by 1H NMR, 13C NMR, FT-IR, mass spectrometry (MS) and elemental analysis. The major advantages of these protocols are mild and green reaction conditions, short reaction times, clean reaction, operational simplicity, easy purification and good to excellent yields with the reusable heterogeneous nanocatalyst. The catalyst was ten recycled without significant loss of activity.
- Sharghi, Hashem,Aboonajmi, Jasem,Mozaffari, Mozhdeh,Doroodmand, Mohammad Mahdi,Aberi, Mahdi
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- Efficient Copper-Catalyzed Synthesis of Substituted Pyrazoles at Room Temperature
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An efficient method for the synthesis of pyrazoles through a copper-catalyzed condensation reaction has been developed. The new catalytic system not only maintained a broad substrate scope but was also active under acid-free reaction conditions, overcoming the conventional requirement for an acid-catalyzed system. Furthermore, the copper catalyst enabled this reaction to be performed at room temperature and in a short reaction time.
- Wang, Haifeng,Sun, Xiangli,Zhang, Shuangling,Liu, Guanglu,Wang, Chunjie,Zhu, Lili,Zhang, Hui
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supporting information
p. 2689 - 2692
(2018/12/14)
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- Direct N-heterocyclization of hydrazines to access styrylated pyrazoles: synthesis of 1,3,5-trisubstituted pyrazoles and dihydropyrazoles
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A microwave-assisted method has been developed for the synthesis of tri-substituted pyrazoles via direct N-heterocyclization of hydrazines with metal-acetylacetonate and -dibenzylideneacetonate without using any base or additives. Most importantly, the synthesis of 1-aryl-5-phenyl-3-styryl-1H-pyrazoles was achieved in a single step using hydrochloride salt of various phenylhydrazines and this is the first report for direct construction of these molecules. The reaction medium and microwave conditions play a critical role for their selective product formation during the reaction. The present reaction explored the usage of metal-diketonic complexes as reaction substrates providing acetylacetone and dibenzylideneacetone moieties to directly participate in cyclization with hydrazines to form the corresponding pyrazoles in excellent yields. The present protocol introduces the important N-heterocyclic moieties in the final structures, giving the reaction great applications from a medicinal chemistry perspective, particularly in the late stage modification strategies in drug discovery.
- Venkateswarlu, Vunnam,Kour, Jaspreet,Kumar, K. A. Aravinda,Verma, Praveen Kumar,Reddy, G. Lakshma,Hussain, Yaseen,Tabassum, Aliya,Balgotra, Shilpi,Gupta, Sorav,Hudwekar, Abhinandan D.,Vishwakarma, Ram A.,Sawant, Sanghapal D.
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p. 26523 - 26527
(2018/08/07)
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- Isocyanide-Induced Activation of Copper Sulfate: Direct Access to Functionalized Heteroarene Sulfonic Esters
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A novel and direct approach to alkyl/aryl heteroarene sulfonic esters using copper sulfate as the environmentally benign inorganic sulfonation reagent was first realized with the aid of isocyanide. A variety of heterocycles reacted to afford the corresponding sulfonic esters through C?H functionalization. In this transformation, the otherwise inert copper sulfate was unusually activated by an isocyanide and employed as the source of the sulfonic substituents in an unprecedented fashion. The findings suggest that an appropriate activator may liberate the chemical activities of some relatively inert inorganic salts for organic synthesis.
- Hong, Xiaohu,Tan, Qitao,Liu, Bingxin,Xu, Bin
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supporting information
p. 3961 - 3965
(2017/03/27)
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- Catalytic selective deuteration of halo(hetero)arenes
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Deuterium labeled aromatic and heteroaromatic compounds are synthesized in good to excellent yields with >98% deuterium purity via palladium catalyzed deuterodehalogenation reaction using commercially available and inexpensive reagents. Selective deuteration of bromoaniline is also demonstrated without H/D exchange in an amino N-H group.
- Janni, Manojkumar,Peruncheralathan
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p. 3091 - 3097
(2016/03/19)
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- Application of Fe3O4@SiO2@sulfamic acid magnetic nanoparticles as recyclable heterogeneous catalyst for the synthesis of imine and pyrazole derivatives in aqueous medium
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Sulfamic acid supported on Fe3O4@SiO2 superpara magnetic nanoparticles was successfully applied as a recyclable solid acid catalyst with a large density of sulfamic acid groups for the synthesis of pyrazole derivatives, an important class of potentially bioactive compounds. The products are obtained in high yield from the one-pot reaction procedure involving dicarbonyl compounds and hydrazines/hydrazides. This new method totally avoids the use of toxic or expensive solvents and organic acids in this reaction.
- Zakerinasab,Nasseri,Hassani,Samieadel
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p. 3169 - 3181
(2016/04/05)
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- Double-nitrogen-containing heterocyclic compound and its preparation method and application (by machine translation)
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The invention belongs to the technical field of organic synthesis, and discloses a nitrogen-containing bisheterocyclic compound, and a preparation method and an application thereof. The general formula of the compound is shown in the specification; and in the specification, R1 is H, p-CH3, p-Cl or p-Br, and R2 is H, p-CH3, p-F, 3,4-di-CH3 or p-Br. The preparation method comprises the following steps: reacting a raw material hydrazinobenzene or substituted hydrazinobenzene hydrochloride with acetylacetone to obtain an aryl pyrazole compound b, formylating the compound under Vilsmeier conditions to obtain a 1-aryl-4-pyrazolylaldehyde compound c in a high yield and high selectivity manner, carrying out aldol condensation on the compound c and acetophenone in a EtOH solvent to obtain a chalcone compound d, and carrying out cyclic condensation on the chalcone compound d and hydrazinobenzene or substituted hydrazinobenzene hydrochloride in the EtOH solvent to obtain the nitrogen-containing bisheterocyclic compound e. The preparation method has the advantages of simple process, mild reaction conditions, high yield, easy post-treatment, maneuverability, and suitableness for large scale preparation.
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Paragraph 0032; 0033
(2016/11/21)
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- PLANT GROWTH REGULATOR COMPRISING ETHYLENE ACTIVE SUBSTANCE
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PROBLEM TO BE SOLVED: To provide a plant growth regulator that has long persistence of ethylene activity and shows non-gaseous ethylene activity with spray easiness. SOLUTION: A plant growth regulator comprises a compound represented by the following general formula (I) [where R1, R2, R3 and R4 each represent a methyl group and others, R5 represents a 5-dimethylaminonaphthalene-1-yl group and others, and n represents an integer of 1 and others] or salt thereof as an active ingredient. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0111
(2016/10/31)
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- 2 (Oxa) as a heterogeneous recyclable catalyst: Synthesis of pyrazoles under mild reaction conditions
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We developed a novel and highly efficient protocol for the synthesis of important pyrazole derivatives by using some 1,3-dicarbonyl compounds and phenyl hydrazines via a one-pot protocol. As a recyclable heterogeneous catalyst, we used [Ce(l-Pro)2]2 (Oxa). In addition, the catalyst is recyclable, the proline is economically viable and readily available in both enantiomeric forms and the catalyst is insoluble in almost all solvents and may be easily filtered off from the reaction medium. Moreover, this new synthetic protocol features high conversion, short reaction times, a straightforward procedure and cleaner reaction profiles.
- Katla, Ramesh,Chowrasia, Rakhi,Manjari, Padma S.,Da Silva, Caren D. G.,Dos Santos, Beatriz F.,Domingues, Nelson L. C.
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supporting information
p. 9471 - 9476
(2016/11/11)
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- Copper-catalyzed C–N cross-coupling of arylboronic acids with N-acylpyrazoles
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A copper-catalyzed C–N bond forming reaction of arylboronic acids and N-acylpyrazoles was developed. This procedure used N-acetyl protected pyrazoles as starting material instead of free pyrazoles (NH). The reaction worked under neutral conditions and did not require any base or ligand. The reaction showed good functional group tolerance.
- Zhang, Jin,Jia, Run-Ping,Wang, Dong-Hui
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p. 3604 - 3607
(2016/07/21)
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- PRODUCING METHOD OF NITROGEN-CONTAINING ORGANIC COMPOUND
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A hydrazine-carbon dioxide-binding compound or hydrazine derivatives 2 carbonyl group react with a compound having one or more nitrogen-containing organic for preparing the compounds of relates to method.
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Paragraph 0417-0419
(2016/12/01)
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- 2-Phenyl-2-(4-phenyl-1 H-1,2,3-triazol-1-yl)ethanol as an efficient and versatile auxiliary ligand in copper(II)-catalyzed Buchwald-Hartwig and Sharpless-Meldal C-N bond-forming reactions
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A highly active, air-stable, and versatile procedure for Buchwald-Hartwig and Sharpless-Meldal C-N bond formation is reported. Under nearly solvent-free conditions using copper(II) acetate and 2-phenyl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)ethanol, a variety of N-heterocycles and various cyclic and noncyclic secondary amines were arylated to form N-aryl compounds in moderate to excellent yields. This methodology also provides rapid access to diverse 1,4-disubstituted 1,2,3-triazoles in good to excellent yields. All reactions are performed in short times under air.
- Sharghi, Hashem,Shiri, Pezhman
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p. 1131 - 1146
(2015/04/14)
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- An efficient practical chemo-enzymatic protocol for the synthesis of pyrazoles in aqueous medium at ambient temperature
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An expeditious oxidative cyclocondensation reaction of hydrazines/hydrazides with 1,3-dicarbonyl compound was efficiently developed in aqueous medium using Saccharomyces cerevisae (baker's yeast) as a whole cell biocatalyst at room temperature. The method has been assigned using green chemistry measures and found to give a range of N-substituted pyrazoles with moderate to excellent yields (70-92%). The reaction progress was monitored by gas chromatography.
- Mane, Ananda,Salokhe, Prabha,More, Pallavi,Salunkhe, Rajashri
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- A modified and practical synthetic route to indazoles and pyrazoles using tungstate sulfuric acid
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Tungstate sulfuric acid-catalyzed Knorr reaction have been used as a simple, rapid, atom economic and green method for the synthesis of indazole and pyrazole derivatives based on the condensation of hydrazine derivatives and ss-dicarbonyl compounds under solvent-free conditions. It was found that the catalyst could be recovered and reused without significant loss of its activity. The use of this method provides a novel and improved modification of Knorr synthesis in terms of clean reaction profile, use of a safe catalyst and solvent-free conditions. A green method for the synthesis of indazole and pyrazole derivatives from the condensation of hydrazine derivatives with dicarbonyl compounds has been described. Tungstate sulfuric acid (TSA) catalyzed efficiently the reactions to give good yields.
- Rahmatzadeh, S. Setareh,Karami, Bahador,Khodabakhshi, Saeed
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- Phenyl/alkyl-substituted-3,5-dimethylpyrazolium ionic liquids
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The synthesis and characterization of a series of new phenyl/alkyl-substituted-3,5-dimethylpyrazolium ionic liquids ([PhpzR][X] R = CnH2n+1 n: 1,2,3,4,5,6,7 [X] = CH3SO3-, BF4-, PF6-) are described. Their melting points, thermal stabilities, electrochemical windows, and solubility properties in common solvents were investigated. They were found to exhibit very good electrochemical and thermal stabilities. The results indicate that these ionic liquids have a high thermal stability up to 374 °C and a large electrochemical window of 4.63 V. The thermophysical properties such as density, viscosity and refractive index were also measured as a function of temperature for the ionic liquids which are in liquid state at room temperature.
- ?zdemir, Melek Canbulat,?zgün, Beytiye
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p. 129 - 135
(2015/02/05)
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- Hexaalkylguanidinium salts as ionic liquids - Applications in titanium and aluminium alcoholate assisted synthesis
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The solubility of titanium and aluminium alcoholates and of titanium tetrakis(trimethylsilanolate) in several hexaalkylguanidinium-based room temperature ionic liquids was screened. The solvent/solute combinations which displayed the highest alcoholate solubility and stability were applied as Lewis-acidic catalytic media for several dehydrating cyclocondensations: lactamisation of ω-aminocarboxylic acids, direct amidation of carboxylic acids, synthesis of oxazolines from carboxylic acids and 2-aminoethanol, lactonisation of 6-hydroxyhexanoic acid, and Paal-Knorr synthesis of pyrroles.
- Arkhipova, Maria,Eichel, Svetlana,Maas, Gerhard
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p. 56506 - 56517
(2015/02/05)
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- Cellulose sulfuric acid as a bio-supported and efficient solid acid catalyst for synthesis of pyrazoles in aqueous medium
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A convenient and practical method was described for the regioselective synthesis of pyrazoles from hydrazines/hydrazides and 1,3-dicarbonyl compounds via the Knorr synthesis in water with cellulose sulfuric acid (CSA) as a biopolymer-based solid acid catalyst. Various hydrazines and hydrazides were reacted with 1,3 diketones and the desired pyrazoles were obtained in high yields. The reaction of less reactive hydrazines with 1,3-dicarbonyl compounds stopped at the corresponding hydrazone derivatives. Hydrazides were employed with β-ketoester, and imine adducts were the only isolated product. Simple isolation of products, mild reaction conditions, reusability of solid acid catalysts and short reaction times are advantages of this green procedure. This journal is
- Nasseri, Mohammad Ali,Salimi, Mehri,Esmaeili, Abbas Ali
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p. 61193 - 61199
(2015/02/19)
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- Copper-catalyzed arylation of nitrogen heterocycles from anilines under ligand-free conditions
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The arylation of pyrazole and derivatives can be achieved by coupling arenediazonium species (formed in situ from anilines) by using a catalytic system that employs low-toxicity and inexpensive copper metal under very mild and ligand-free conditions (T = 20 ° C). From other nitrogen heterocycles, the presence of an additive (NBu4I) significantly improves the efficiency of the catalytic system. These results represent the first examples of C-N bond formation from arenediazonium species.
- Toummini, Dounia,Tlili, Anis,Bergs, Julien,Ouazzani, Fouad,Taillefer, Marc
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supporting information
p. 14619 - 14623
(2015/01/09)
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- Ionic liquid promoted synthesis of β-Enamino ketones and esters under microwave irradiation
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A facile amination of 1,3-dicarbonyl compounds with amines or ammonium salts has been achieved under microwave irradiation in the presence of acidic ionic liquid 1-butyl-3-methylimidazolium hydrogen sulphate. The method has the advantage of solvent free reactions, short reaction time and mild conditions.
- Singh, Ashima,Gupta, Neeru,Sharma,Singh, Jasvinder
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p. 900 - 906
(2014/08/05)
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- Diazirines as potent electrophilic Nitrogen sources: Application to the synthesis of Pyrazoles
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Even after more than 50 years since its discovery, the electrophilic potential of diazirines was never truly exploited. This longstanding limitation has been resolved. N-Monosubstituted diaziridines and hydrazones are obtained by nucleophilic additions. They release, under hydrolysis conditions, the corresponding monosubstituted hydrazines. The latter were converted to pyrazoles in high yields. The adamantanone can be recovered in 80-100% yields. This work demonstrates the potential of diazirines as electrophilic nitrogen sources with recoverable protecting groups.
- Schneider, Yoann,Prévost, Julie,Gobin, Ma?lle,Legault, Claude Y.
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p. 596 - 599
(2014/04/03)
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- BippyPhos: A single ligand with unprecedented scope in the Buchwald-Hartwig amination of (hetero)aryl chlorides
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Over the past two decades, considerable attention has been given to the development of new ligands for the palladium-catalyzed arylation of amines and related NH-containing substrates (i.e., Buchwald-Hartwig amination). The generation of structurally diverse ligands, by research groups in both academia and industry, has facilitated the accommodation of sterically and electronically divergent substrates including ammonia, hydrazine, amines, amides, and NH heterocycles. Despite these achievements, problems with catalyst generality persist and access to multiple ligands is necessary to accommodate all of these NH-containing substrates. In our quest to address this significant limitation we identified the BippyPhos/[Pd(cinnamyl)Cl]2 catalyst system as being capable of catalyzing the amination of a variety of functionalized (hetero)aryl chlorides, as well as bromides and tosylates, at moderate to low catalyst loadings. The successful transformations described herein include primary and secondary amines, NH heterocycles, amides, ammonia and hydrazine, thus demonstrating the largest scope in the NH-containing coupling partner reported for a single Pd/ligand catalyst system. We also established BippyPhos/ [Pd(cinnamyl)Cl]2 as exhibiting the broadest demonstrated substrate scope for metal-catalyzed cross-coupling of (hetero)aryl chlorides with NH indoles. Furthermore, the remarkable ability of BippyPhos/[Pd(cinnamyl)Cl] 2 to catalyze both the selective monoarylation of ammonia and the N-arylation of indoles was exploited in the development of a new one-pot, two-step synthesis of N-aryl heterocycles from ammonia, ortho- alkynylhalo(hetero)arenes and (hetero) aryl halides through tandem N-arylation/hydroamination reactions. Although the scope in the NH-containing coupling partner is broad, BippyPhos/[Pd(cinnamyl)Cl]2 also displays a marked selectivity profile that was exploited in the chemoselective monoarylation of substrates featuring two chemically distinct NH-containing moieties.
- Crawford, Sarah M.,Lavery, Christopher B.,Stradiotto, Mark
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supporting information
p. 16760 - 16771
(2014/01/06)
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- Mixing with microwaves: Solvent-free and catalyst-free synthesis of pyrazoles and diazepines
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A simple and facile condensation of hydrazines/hydrazides and diamines with 1,3-diketones/β-ketoester leads to the preparation of pyrazoles and diazepines in high yields. This eco-friendly protocol is accelerated by microwave heating and efficiently carried out without any reaction solvent or catalyst in as little as 5 min.
- Vaddula, Buchi Reddy,Varma, Rajender S.,Leazer, John
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supporting information
p. 1538 - 1541
(2013/03/14)
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- PEG-SO3H as a mild, efficient and green catalytic system for the synthesis of pyrazole derivatives in aqueous medium
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A versatile, alternative and environmentally benign strategy for the synthesis of a series of pyrazoles has been successfully performed in water using PEG-SO3H as an acidic catalyst. The products are obtained in high yield from the one-pot reaction procedure involving dicarbonyl compounds and hydrazines/hydrazides. This new method totally avoids the use of organic acids and toxic or expensive solvents in this reaction. The catalyst is waste-free, easily prepared, and efficiently re-used.
- Nasseri,Alavi,Zakeri Nasab
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p. 213 - 219
(2013/07/26)
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- Hydrotrope: Green and rapid approach for the catalyst-free synthesis of pyrazole derivatives
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An efficient synthesis of pyrazole derivatives by condensation of 1,3-diketone and hydrazines/hydrazides has been achieved in aqueous hydrotropic solution under catalyst-free conditions within a very short time. The present protocol is beneficial as it includes mild reaction conditions, shorter reaction times, use of universal solvent water, which avoids volatile organic solvents, high yields of products, and being environmentally friendly.
- Barge, Madhuri,Kamble, Santosh,Kumbhar, Arjun,Rashinkar, Gajanan,Salunkhe, Rajashri
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p. 1213 - 1218
(2013/08/23)
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- Correlation of spectroscopically determined ligand donor strength and nucleophilicity of substituted pyrazoles
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The relative ligand donor strengths of 10 pyrazole-derived ligands has been determined with great accuracy, making use of the interdependence between the donor strength of the co-ligand and the 13C NMR chemical shift of the iPr2-bimy carbene signal in trans-[PdBr2( iPr2-bimy)L] complexes (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene; L = pyrazole-derived ligand). Even subtle variations in the substitution pattern of the pyrazole backbone up to three bonds away from the coordinating nitrogen could be detected reliably using this methodology. Alkylation experiments conducted on the pyrazoles using electrophiles of varied reactivity (ethyl bromide, ethyl iodide, and trimethyloxonium tetrafluoroborate) served as a benchmark to rank the pyrazoles in three groups of gradually increasing nucleophilicity, which correlated well with their determined donor strength.
- Bernhammer, Jan Christopher,Huynh, Han Vinh
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supporting information; experimental part
p. 8600 - 8608
(2012/10/07)
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- Highly efficient and simple catalytic system for the N-arylation of some hindered aza-heterocycles in water
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A highly efficient and simple protocol for the N-arylation of some hindered aza-heterocycles in water has been developed with readily available basic copper carbonate as the catalyst using bis(3,5-dimethyl-1H-pyrazol-1-yl)methane as ligand. This mild catalytic system possesses excellent tolerance for a large variety of functional groups. A total of 11 previously unknown coupling products have been synthesized by this methodology.
- Mukhopadhyay, Chhanda,Tapaswi, Pradip Kumar
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experimental part
p. 2217 - 2228
(2012/06/18)
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- Sulfamic acid (H2NSO3H): A low-cost, mild, and efficient catalyst for the synthesis of substituted N-Phenylpyrazoles under solvent-free conditions
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N-Phenylpyrazoles are synthesized by condensing phenylhydrazine and 1,3-diketones in the presence of a catalytic amount of sulfamic acid, a mild and an efficient solid acid catalyst, under solvent-free conditions. This condensation proceeds smoothly in shorter reaction time. Copyright Taylor & Francis Group, LLC.
- Shetty, Mohan R.,Samant, Shriniwas D.
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experimental part
p. 1411 - 1418
(2012/04/17)
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- Synthesis and antimicrobial activity of linked heterocyclics containing pyrazole-pyrimidine rings
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New series of 4-(aryl/hetaryl)-6-(3,5-dimethyl-1-phenyl-1H-4-pyrazolyl)-2- pyrimidinamine 5a-j has been prepared and confirmed by IR, NMR, MS and elemental analyses. All the synthesized compounds have been tested for their antimicrobial activity against bacteria and fungi. Among the synthesized compounds, the compounds containing 4-nitrophenyl 5c, 2-furyl 5h and 2-thiazolyl 5j at 6-position of pyrimidine ring are highly active against all the organisms employed.
- Sanjeeva Reddy,Vani Devia,Rajesh Kumara,Sanjeeva Raoa,Nagarajb
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experimental part
p. 1181 - 1186
(2011/10/12)
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- Synthesis of novel linked pyrazolyl-thiazolidinone heterocycles as potent antibacterial agents
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A novel series of 2-(3,5-dimethyl-1-phenyl-1H-4-pyrazolyl)-3-(aryl/ heteroaryl)-1,3-thiazolidin-4-one derivatives 4a-h has been synthesized readily in one-pot from 3,5-dimethyl-1-phenyl-1H-4-pyrazolecarbaldehyde (3), and characterized via IR, NMR, MS and elemental analyses. Further, these compounds were screened for antibacterial (MIC) activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Staphylococcus pyogenes. Amongst them, compounds containing pyridyl 4g and pyrimidinyl 4h moiety exerted superior antibacterial activity against S. aureus and E. coli at the concentration of 6.25 μg/mL, which is less than the concentration of the standards neomycin and streptomycin, and emerged as potential molecules for further development.
- Reddy, Cherkupally Sanjeeva,Kumar, Gaddam Rajesh,Devi, MacHerla Vani,Nagaraj, Adki
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experimental part
p. 576 - 581
(2012/04/18)
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- Cu(OAc)2·H2O-catalyzed N-arylation of nitrogen-containing heterocycles
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In the absence of any additional ligands, the efficient N-arylation of nitrogen-containing heterocycles with aryl iodides catalyzed by relative low catalyst amount of Cu(OAc)2·H2O was developed. This simple catalytic system is involved in the C-N cross-coupling reaction and works for a variety of pyrazole, pyrrole, imidazole, triazole, indole, benzoimidazole, benzotriazole, carbazole, and anilines as well as aryl iodides with different electronic properties. Highly efficient copper(II)-catalyzed N-arylation protocol was established.
- Xu, Zhong-Lin,Li, Hong-Xi,Ren, Zhi-Gang,Du, Wei-Yuan,Xu, Wei-Chang,Lang, Jian-Ping
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supporting information; experimental part
p. 5282 - 5288
(2011/08/04)
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- Magnetic Nanoparticle-Supported Glutathione as a Sustainable Organocatalyst
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This invention relates to the use of nano-organocatalysts, and, more specifically, to the use of magnetic nanomaterial-supported organocatalysts. It is an object of the present invention to provide “green” catalysts and protocols. According to one embodiment of the invention, a nano-organocatalyst in the form of a magnetic nanomaterial-supported organocatalyst is provided. According to other embodiments of the invention, glutathione and cysteine are provided as organocatalysts and magnetic nanomaterial-supported glutathione and magnetic nanomaterial-supported cysteine are provided for use as nano-organocatalysts. According to another embodiment of the invention, a method of using a recyclable magnetic nanomaterial-supported organocatalyst using a totally benign aqueous protocol, without using any organic solvent in the reaction or during the workup, is provided. According to a further embodiment of the invention, a recyclable magnetic nanomaterial-supported organocatalyst for various organocatalytic reactions, including but not limited to Paal-Knorr reactions, aza-Michael addition and pyrazole synthesis, is provided.
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Page/Page column 9
(2011/04/14)
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