- A solvent-free manganese(II) -catalyzed Clauson-Kaas protocol for the synthesis of N-aryl pyrroles under microwave irradiation
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The first manganese-catalyzed modified Clauson-Kaas reaction for N-substituted pyrrole synthesis using 2,5-dimethoxytetrahydrofuran with variously substituted aromatic amines has been developed (up to 89% yield). This interesting neat strategy is free from additives including co-catalysts, ligands, and acids. Relatively low cost, environmentally benign, and handy Mn(NO3)2·4H2O is employed as the catalyst under microwave conditions with a very short reaction time (20?min). The above qualities attest to the green nature of this reaction.
- Rohit, Kizhakkekuttu Radhakrishnan,Meera, Gopinadh,Anilkumar, Gopinathan
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supporting information
p. 194 - 200
(2021/10/12)
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- Utilization of caffeine carbon supported cobalt catalyst in the tandem synthesis of pyrroles from nitroarenes and alkenyl diols
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Employing bio-waste caffeine carbon-supported heterogeneous cobalt catalyst, synthesis of various substituted pyrrole derivatives is reported. In this methodology, pyrroles were synthesized through coupling between nitroarenes and alkenyl diols in a tandem manner. Among all the heterogeneous catalysts Co(OAc)2-CC-800 displayed the highest catalytic activity. Preparative scale synthesis of pyrroles and synthesis of anti-tubercular agent 5-(4-(1H-pyrrol-1-yl)phenyl)-1,3,4-oxadiazole-2-thiol revealed the practical applicability of this protocol. Several kinetic experiments and Hammett studies were conducted to understand the probable mechanism and electronic effects on this transformation.
- Balasubramaniam, Bhuvaneshwari,Dhara, Partha,Gupta, Raju K.,Kundu, Sabuj,Panja, Dibyajyoti,Sau, Anirban
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p. 244 - 254
(2021/09/07)
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- Cascade Synthesis of Pyrroles from Nitroarenes with Benign Reductants Using a Heterogeneous Cobalt Catalyst
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A bifunctional 3d-metal catalyst for the cascade synthesis of diverse pyrroles from nitroarenes is presented. The optimal catalytic system Co/NGr-C@SiO2-L is obtained by pyrolysis of a cobalt-impregnated composite followed by subsequent selective leaching. In the presence of this material, (transfer) hydrogenation of easily available nitroarenes and subsequent Paal–Knorr/Clauson-Kass condensation provides >40 pyrroles in good to high yields using dihydrogen, formic acid, or a CO/H2O mixture (WGSR conditions) as reductant. In addition to the favorable step economy, this straightforward domino process does not require any solvents or external co-catalysts. The general synthetic utility of this methodology was demonstrated on a variety of functionalized substrates including the preparation of biologically active and pharmaceutically relevant compounds, for example, (+)-Isamoltane.
- Ryabchuk, Pavel,Leischner, Thomas,Kreyenschulte, Carsten,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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supporting information
p. 18679 - 18685
(2020/09/02)
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- Ligand and Cu freeN-arylation of indoles, pyrroles and benzylamines with aryl halides catalyzed by a Pd nanocatalyst
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Herein, theN-arylation of aromatic heterocycles like indoles and pyrroles is reported by a Pd nanocatalyst under ligand- and Cu-free conditions. The reaction conditions tolerate several functional groups and work very efficiently for aryl iodides and bromides. Aryl chlorides are also successful as the coupling partners albeit with lower yields. The methodology is also applicable for theN-arylation of aliphatic primary amines as demonstrated by the reactions of benzylamine with several aryl iodides as well as bromides. The recyclable Pd nanocatalyst catalyzes the reaction by a heterogeneous mechanism, which has been demonstrated by several techniques including the three phase test and thein situICP-MS analysis of the reaction mixture.
- Paul, Abhijit,Chatterjee, Debnath,Banerjee, Srirupa,Yadav, Somnath
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supporting information
p. 14447 - 14452
(2020/09/21)
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- Ni-Catalyzed β-Alkylation of Cyclopropanol-Derived Homoenolates
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Metal homoenolates are valuable synthetic intermediates which provide access to β-functionalized ketones. In this report, we disclose a Ni-catalyzed β-alkylation reaction of cyclopropanol-derived homoenolates using redox-active N-hydroxyphthalimide (NHPI) esters as the alkylating reagents. The reaction is compatible with 1°, 2°, and 3° NHPI esters. Mechanistic studies imply radical activation of the NHPI ester and 2e β-carbon elimination occurring on the cyclopropanol.
- Mills, L. Reginald,Zhou, Cuihan,Fung, Emily,Rousseaux, Sophie A. L.
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supporting information
p. 8805 - 8809
(2019/11/03)
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- Copper(I)-USY as a Ligand-Free and Recyclable Catalyst for Ullmann-Type O-, N-, S-, and C-Arylation Reactions: Scope and Application to Total Synthesis
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The copper(I)-doped zeolite CuI-USY proved to be a versatile, efficient, and recyclable catalyst for various Ullmann-type coupling reactions. Easy to prepare and cheap, this catalytic material enables the arylation and heteroarylation of diverse O-, N-, S-, and C-nucleophiles under ligand-free conditions while exhibiting large functional group compatibility. The facility of this catalyst to promote C-O bond formation was further demonstrated with the total synthesis of 3-methylobovatol, a naturally occurring diaryl ether of biological relevance. From a mechanistic viewpoint, two competitive pathways depending on the nature of the nucleophile and consistent with the obtained results have been proposed.
- Garnier, Tony,Danel, Mathieu,Magné, Valentin,Pujol, Anthony,Bénéteau, Valérie,Pale, Patrick,Chassaing, Stefan
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p. 6408 - 6422
(2018/05/31)
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- Pyrrolyl pyrazoline carbaldehydes as Enoyl-ACP reductase inhibitors: Design, synthesis and antitubercular activity
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Introduction: In efforts to develop new antitubercular (anti-TB) compounds, herein we describe cytotoxic evaluation of 15 newly synthesized pyrrolyl pyrazoline carbaldehydes. Method & Materials: Surflex-Docking method was used to study binding modes of th
- Dixit, Sheshagiri R.,Joshi, Shrinivas D.,Kulkarni, Venkatarao H.,Jalalpure, Sunil S.,Kumbar, Vijay M.,Mudaraddi, Tulasigiriyappa Y.,Nadagouda, Mallikarjuna N.,Aminabhavi, Tejraj M.
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- Synthesis of new pyrazolyl pyrrole derivatives as antitubercular agents
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A series of pyrrole-containing biheterocyclic derivatives was synthesized, using substituted chalacone derivatives (4a-q) as a precursor, which were prepared by the reaction of substituted benzaldehyde (1a-q) with 4-(1H-pyrrol-1-yl)-acetophenone (2) in 40
- Hallikeri, Channabasappa S.,Joshi, Shrinivas D.,Yenni, Bhimsen,Dixit, Sheshagiri,Kulkarni, Venkatarao H.
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- Synthesis, antimycobacterial screening and ligand-based molecular docking studies on novel pyrrole derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties
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We report here the synthesis, antibacterial and antitubercular evaluation of 61 novel pyrrolyl derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties. Molecular docking was carried out on enoyl ACP reductase from Mycobacterium tuberculsosi
- Joshi, Shrinivas D.,Dixit, Sheshagiri R.,Kirankumar,Aminabhavi, Tejraj M.,Raju,Narayan, Ramanuj,Lherbet, Christian,Yang, Kap Seung
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p. 133 - 152
(2015/11/18)
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- An efficient heterogeneous catalytic method for the N-arylation of pyrrole and other N-heterocycles
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Abstract 4 ? molecular sieve modified with copper(0) or copper(II) is an efficient heterogeneous catalyst for the arylation of pyrrole and some other heterocycles with iodo- or bromoarenes, Cs2CO3 base and pyrrole (or DMF) solvent. The catalysts can be easily prepared and are reusable.
- Nmeth, Jnos,Debreczeni, Nra,Gresits, Ivn,Blint, Mria,Hell, Zoltn
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p. 1113 - 1119
(2015/08/06)
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- Ligand-free N-arylation of heterocycles using metal-organic framework [Cu(INA)2] as an efficient heterogeneous catalyst
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A metal-organic framework [Cu(INA)2] was synthesized and used as a heterogeneous catalyst for arylation of a wide range of N-H heterocycles and aryl halides under ligand-free conditions. The N-arylation reaction involved the use of 5 mol% Cu-MOF catalyst with K3PO4 or tBuOLi as the base in dimethylacetamide (DMA) solvent at 100 °C in 6 h. [Cu(INA)2] exhibited higher catalytic activity for the N-arylation transformation than that of common homogeneous copper catalysts and other Cu-MOFs with unsaturated open metal sites such as Cu2(BDC)2(BPY), Cu3(BTC)2, and Cu2(BDC)2(DABCO). Interestingly, reaction conditions are compatible with a wide range of N-H heterocycles, functional groups, and aryl chlorides. A leaching test indicated no contribution of leached active species in the reaction filtrate. Furthermore, the [Cu(INA)2] catalyst could be facilely separated from the reaction mixture and recovered and reused several times without a significant degradation in catalytic activity.
- Truong, Thanh,Nguyen, Chi V.,Truong, Ngoc T.,Phan, Nam T. S.
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p. 107547 - 107556
(2016/01/09)
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- Design, synthesis, molecular docking and 3D-QSAR studies of potent inhibitors of enoyl-acyl carrier protein reductase as potential antimycobacterial agents
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In order to develop a lead antimycobacterium tuberculosis compound, a series of 52, novel pyrrole hydrazine derivatives have been synthesized and screened which target the essential enoyl-ACP reductase. The binding mode of the compounds at the active site of enoyl-ACP reductase was explored using surflex-docking method. The binding model suggests one or two hydrogen bonding interactions between pyrrole hydrazones and InhA enzyme. Highly active compound 5r (MIC 0.2 μg/mL) showed hydrogen bonding interactions with Tyr158 and NAD+ in the same manner as those of ligands PT70 and triclosan. The CoMFA and CoMSIA models generated with database alignment were the best in terms of overall statistics. The predictive ability of the CoMFA and CoMSIA models was determined using a test set of 13 compounds, which gave predictive correlation coefficients (rpred2) of 0.896 and 0.930, respectively.
- More, Uttam A.,Joshi, Shrinivas D.,Aminabhavi, Tejraj M.,Gadad, Andanappa K.,Nadagouda, Mallikarjuna N.,Kulkarni, Venkatrao H.
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p. 199 - 218
(2014/01/06)
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- L-(+)-Tartaric acid and choline chloride based deep eutectic solvent: An efficient and reusable medium for synthesis of N-substituted pyrroles via Clauson-Kaas reaction
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l-(+)-Tartaric acid-choline chloride based deep eutectic solvent has been found to be an effective promoted medium for Clauson-Kaas reaction of aromatic amines and 2,5-dimethoxytetrahydrofuran. Structurally diverse N-substituted pyrroles were obtained in high to excellent yields under mild conditions. The deep eutectic solvent is inexpensive, non-toxic, reusable and biodegradable.
- Wang, Ping,Ma, Fei-Ping,Zhang, Zhan-Hui
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p. 259 - 262
(2014/11/07)
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- A recyclable magnetic nanoparticles supported antimony catalyst for the synthesis of N-substituted pyrroles in water
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A new magnetic nanoparticle-supported antimony catalyst was prepared and evaluated as a recoverable catalyst for Clauson-Kaas reaction. The reaction proceeds efficiently in aqueous medium to give the corresponding N-substituted pyrroles in high yield. The immobilized catalyst could be easily recovered by magnetic separation and recycled for six times without significant loss of its catalytic activity.
- Ma, Fei-Ping,Li, Pei-He,Li, Bao-Le,Mo, Li-Ping,Liu, Ning,Kang, Hui-Jun,Liu, Ya-Nan,Zhang, Zhan-Hui
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- Synthesis of pyrrole derivatives from diallylamines by one-pot tandem ring-closing metathesis and metal-catalyzed oxidative dehydrogenation
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A series of aryl-substituted pyrrole derivatives was synthesized from diallylamines through a ruthenium carbene catalyzed ring-closing metathesis reaction and in situ oxidative dehydrogenation reaction catalyzed by FeCl 3·6H2O or CuCl2·2H2O in the presence of O2. The reaction was mild, simple, and convenient. An oxygen atmosphere played a critical role in obtaining high conversion of substituted pyrroles in the proposed catalytic system.
- Chen, Weiqiang,Wang, Jianhui
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supporting information
p. 1958 - 1963
(2013/05/08)
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- Novel approach for the synthesis of N-Substituted pyrroles starting directly from nitro compounds in water
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A novel approach for a facile high-yielding synthesis of N-substituted pyrroles has been discovered by the treatment of nitroarenes with 2,5-dimethoxytetrahydrofuran using indium in dilute aqueous HCl at room temperature. Taylor & Francis Group, LLC.
- Das, Biswanath,Shinde, Digambar Balaji,Kanth, Boddu Shashi,Kumar, Jayprakash Narayan
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experimental part
p. 548 - 553
(2011/11/29)
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- Assisted tandem catalytic RCM-aromatization in the synthesis of pyrroles and furans
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An assisted tandem catalytic transformation of diallyl amines and diallyl ethers into N-aryl pyrroles and furans, respectively, is described. The sequence relies on ring closing metathesis followed by dehydrogenation of the initially formed dihydropyrroles and dihydrofurans. Both steps are Ru-catalyzed, but the sequence requires only one precatalyst, because conversion of the metathesis catalyst into the dehydrogenation catalyst is achieved in situ, triggered by the oxidant tert-butyl hydroperoxide.
- Schmidt, Bernd,Krehl, Stefan,Jablowski, Eric
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p. 5119 - 5130
(2012/08/07)
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- Antimalarial Activity of Newly Synthesized Chalcone Derivatives In Vitro
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Twenty-seven novel chalcone derivatives were synthesized using Claisen-Schmidt condensation and their antimalarial activity against asexual blood stages of Plasmodium falciparum was determined. Antiplasmodial IC50 (half-maximal inhibitory concentration) activity of a compound against malaria parasites in vitro provides a good first screen for identifying the antimalarial potential of the compound. The most active compound was 1-(4-benzimidazol-1-yl-phenyl)-3-(2, 4-dimethoxy-phenyl)-propen-1-one with IC50 of 1.1μg/mL, while that of the natural phytochemical, licochalcone A is 1.43μg/mL. The presence of methoxy groups at position 2 and 4 in chalcone derivatives appeared to be favorable for antimalarial activity as compared to other methoxy-substituted chalcones. Furthermore, 3, 4, 5-trimethoxy groups on chalcone derivative probably cause steric hindrance in binding to the active site of cysteine protease enzyme, explaining the relative lower inhibitory activity.
- Yadav, Neesha,Dixit, Sandeep K.,Bhattacharya, Amit,Mishra, Lokesh C.,Sharma, Manish,Awasthi, Satish K.,Bhasin, Virendra K.
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experimental part
p. 340 - 347
(2012/08/29)
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- Use of acylhydrazine- and acylhydrazone-type ligands to promote CuI-catalyzed C-N cross-coupling reactions of aryl bromides with N-heterocycles
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A series of ten acylhydrazine- and acylhydrazone-type ligands were designed and synthesized. Their electronic and steric properties were easily modified and tuned by varying the substituents in the vicinity of the acylhydrazine and acylhydrazone units. The effect of ligands on the catalytic activity of Ullmann reactions was assessed by using a combination of these ligands with CuI. The catalytic system is very efficient for the C-N coupling reaction of azoles with aryl and heteroaryl bromides. A simple and efficient procedure for copper-catalyzed C-N cross-coupling reactions between aryl bromides and NH-containingheterocycles is illustrated. Readily available acylhydrazine- and acylhydrazone-typeligands promote the reaction.
- Li, Liuyi,Zhu, Lei,Chen, Dagui,Hu, Xuelei,Wang, Ruihu
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experimental part
p. 2692 - 2696
(2011/06/25)
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- Copper ferrite nanoparticle-mediated N-arylation of heterocycles: A ligand-free reaction
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The synergistic effects of iron and copper in copper ferrite nanoparticles for the N-arylation of heterocycles with aryl halides were demonstrated. The magnetic nature of the catalyst facilitates its removal from the reaction medium for further use. Negligible leaching of Cu and Fe in consecutive cycles makes the catalyst economical and environmentally benign for C-N cross-coupling reactions.
- Panda, Niranjan,Jena, Ashis Kumar,Mohapatra, Sasmita,Rout, Smruti Ranjan
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supporting information; experimental part
p. 1924 - 1927
(2011/04/25)
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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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- New conjugated monomers and oligomers derived from chalcones and containing thiophene, pyrrole, and pyrimidine fragments
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4New hybrid systems based on a series of chalcones and containing pyrimidine, thiophene, and pyrrole fragments were synthesized, and their electrochemical properties were studied. Pleiades Publishing, Ltd., 2010.
- Bushueva,Shklyaeva,Abashev
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experimental part
p. 1444 - 1449
(2011/03/17)
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- CuCl-catalyzed formation of C-N bond with a soluble base
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Tetramethylammonium hydroxide was used as a base instead of a traditional inorganic base in this copper-catalyzed system and some satisfactory results were obtained. Various functional groups were compatible under this reaction condition.
- Feng, Yi-Si,Man, Qiu-Shi,Pan, Pan,Pan, Zong-Qin,Xu, Hua-Jian
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experimental part
p. 2585 - 2588
(2009/08/07)
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- Synthesis of novel substituted 1,3-diaryl propenone derivatives and their antimalarial activity in vitro
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The synthesis of novel 1,3-diaryl propenone derivatives and their antimalarial activity in vitro against asexual blood stages of human malaria parasite, Plasmodium falciparum, are described. Chalcone derivatives were prepared via Claisen-Schmidt condensation of substituted aldehydes with substituted methyl ketones. Antiplasmodial IC50 (half maximal inhibitory concentration) activity of these compounds ranged between 1.5 and 12.3 μg/ml. The chloro-series, 1,2,4-triazole substituted chalcone was found to be the most effective in inhibiting the growth of P. falciparum in vitro while pyrrole and benzotriazole substituted chalcones showed relatively less inhibitory activity. This is the first report on antiplasmodial activity of chalcones with azoles on acetophenone ring.
- Mishra, Nidhi,Arora, Preeti,Kumar, Brajesh,Mishra, Lokesh C.,Bhattacharya, Amit,Awasthi, Satish K.,Bhasin, Virendra K.
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p. 1530 - 1535
(2008/09/21)
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- Synthesis of Cu2O coated Cu nanoparticles and their successful applications to Ullmann-type amination coupling reactions of aryl chlorides
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We synthesized uniform Cu2O coated Cu nanoparticles from the thermal decomposition of copper acetylacetonate followed by air oxidation and used these nanoparticles as catalysts for Ullmann type amination coupling reactions of aryl chlorides.
- Son, Seung Uk,Park, In Kyu,Park, Jongnam,Hyeon, Taeghwan
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p. 778 - 779
(2007/10/03)
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- Reductive one batch synthesis of N-substituted pyrrolidines from primary amines and 2,5-dimethoxytetrahydrofuran
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The construction of the pyrrolidine ring about a nitrogen of a primary amine by a reductive condensation reaction using 2,5- dimethoxytetrahydrofuran and sodium borohydride in acidic water medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electron effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups. The reaction allows the introduction of two deuterium atoms, with label conservation, in both the α-positions of the pyrrolidine ring by the use of sodium borodeuteride instead of sodium borohydride.
- Verardo, Giancarlo,Dolce, Anna,Toniutti, Nicoletta
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-