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- Volume 9, Issue 3, 2012
Letters in Organic Chemistry - Volume 9, Issue 3, 2012
Volume 9, Issue 3, 2012
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Efficient Synthesis of 3-Aminoimidazo[1,2-a] Pyridines Using Silica-Supported Perchloric Acid (HClO4-SiO2) as a Novel Heterogenous Catalyst
Authors: Azizollah Habibi, Zahra Tarameshloo, Shahnaz Rostamizadeh and Ali M. AmaniOne pot three-component reaction of 2-amino pyridines, aldehydes and isocyanides in the presence of silicasupported perchloric acid (HClO4-SiO2), produces 3-aminoimidazo[1,2-a] pyridines in excellent yields. The reaction time is short and work up of reaction is very easy. New compounds were identified by IR, 1H NMR, 13C NMR and Mass spectrum.
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Alkyne-Azide Cycloaddition Catalyzed by Fe-Cu Nanoparticles
1,2,3-triazoles were synthesized using several alkynes and azides as starting materials in the presence of catalytic amounts of Cu-Fe nanoparticles. The process represents many advantages because it does not require additional bases or reductants, and this is carried out under ambient pressure and temperature with good yields.
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Magnetic Nanoparticles Catalyzed N-Tert-Butoxycarbonylation of Amines and Amine Derivatives
Authors: Jafar Akbari, Soghra B. Sajirani, Jafar M. Nezhad and Akbar HeydariA simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using magnetically recoverable γ-Fe2O3@SiO2 nanoparticles is reported. The catalyst can be easily recovered and recycled without a significant loss in the catalytic activity. No competitive side reactions, such as formation of isocyanate, urea, oxazolidinone, and N,N-di-Boc derivati Read More
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Enantiodivergent Chemoenzymatic Synthesis of (S)- and (R)-(Z)-9-Dodecyl-4,5,8,9-tetrahydro-3H-oxonin-2-one as Analogues of Topsentolides
Authors: Isolde Wetzel, Jurgen Krauss and Franz Bracher(Z)-4,5,8,9-Tetrahydro-3H-oxonin-2-one is the core of naturally occurring topsentolides, cytotoxic oxylipins isolated from a marine sponge of the genus Topsentia. An enantiodivergent approach to topsentolide analogues was worked out with a lipase-catalyzed kinetic resolution of a secondary alcohol and a ring-closing metathesis giving the unsaturated nine-membered lactone as key steps.
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Regioselective C-S Bond Formation Accomplished by Regioselective C-F Substitution of Polyfluoroarenes with Substituted Thiophenols
Authors: Qizhong Zhou, Bin Zhang, Haining Gu, Aiguo Zhong, Tieqi Du, Qiong Zhou, Yuyuan Ye, Zhengneng Jin, Huajiang Jiang and Rener ChenThe nucleophilic aromatic substitution reaction of pentafluorobenzene, methyl 2,3,4,5-tetrafluorobenzoic acid ester and 1,2,4,5-tetrafluorobenzene with substituted thiophenols showed good regioselectivity while pentafluorobenzene gave high yields. The computational results suggest that the specificity difference between polyfluorobenzenes originates from their electronic properties.
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A New and Efficient Method for the Preparation of 2,4,6,8-Tetraazabicyclo[3.3.0]octane-3,7-diones (Glycolurils) Catalyzed by Keggin, Wells-Dawson, and Preyssler Heteropolyoxometalates, Effect of Structure on the Reactivity
Authors: Reza Tayebee, Rezaei-Seresht Esmaeil and Maleki BehroozSome important cis- and trans-alkyl substituted glycolurils were prepared via condensation of vicinal dicarbonyl compounds with urea and/or methylurea catalyzed by 0.95 mol% of Keggin- type H3PW12O40 under environmentally benign and simple condition. Proficiency of structurally different heteropolyoxometalates, including Keggin, Wells-Dawson, and Preyssler, was investigated in the reaction of urea with 2, 3-buta Read More
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An Unusual and Chemoselective Reduction of Ester Grouping in Nsubstituted-3-acetylindoles by Sodium Borohydride
Authors: Muvvala Venkatanarayana and Pramod K. DubeyTreatment of 3-acetylindoles 1(a-e) with ethyl chloroacetate in the presence of K2CO3 and tetrabutylammoniumbromide (TBAB) as phase transfer catalyst in DMF, resulted in the formation of the corresponding N-substituted derivatives, ethyl 2-(3-acetyl-1H-indol-1-yl)acetate 2(a-e) which on reaction with NaBH4 yielded, unexpectedly, ethanol derivatives, 1-(1-(2-hydroxyethyl)-1H-indol-3-yl)ethanone 3(a-e) by the unusual and Read More
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P2O5 Promoted One-Pot Synthesis of 3-aminoimidazo[1,2-a]pyridines under Solvent-Free Conditions
Authors: Ebrahim Soleimani, Mojtaba Taran, Mohsen Zainali and Shahram LotfiA facile, efficient and environment-friendly protocol for the synthesis of 3-aminoimidazo[1,2-a]pyridines has been developed by one-pot condensation of 2-aminopyridine, aromatic aldehyde and alkyl or aryl isocyanide in the presence of P2O5 as catalyst under solvent-free conditions at room temperature. The present approach offers the advantages of clean reaction, simple methodology, short reaction time, high yiel Read More
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Synthesis, Characterization and In Vitro Evaluation of Self-Assembled poly(ethylene glycol)-glycyrrhetinic Acid Conjugates
Authors: Gu He, Zhiyao He, Xi Zheng, Junmin Li, Chi Liu, Xiangrong Song, Liang Ouyang and Fengbo WuGlycyrrhetinic acid (GA) is a commonly used drug for the chemotherapy of Chronic Hepatitis B, allergic dermatitis, inflammation, etc. But some problems such as poor water-solubility, low bioavailability and short plasma halflife, have limited its use. In the present study, PEGylation derivatives of GA derivatives were synthesized and characterized by FTIR, NMR, transmission electron microscopy, particle size analysis, etc. The PE Read More
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Synthesis and Electronic Properties of Phenothiazinyl Primary Amines
Authors: Larisa N. Mataranga-Popa, Adam W. Franz, Sarah Bay and Thomas J.J. MullerPhenothiazinyl primary amines were synthesized in moderate to excellent yields from cyano (oligo)phenothiazines by reduction with LiAlH4 in diethyl ether or with nBuNBH4 in dichloromethane. All representatives show first reversible oxidation waves, they are UV absorbing and dimers emit blue-green light upon UV excitation with substantial quantum yield.
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Synthesis of 3-Aroylcoumarin-Flavone Hybrids
Authors: Hulluru S.P. Rao and Venkata S. TangetiA facile two step synthesis of 3-aroylcoumarin-flavone hybrids was achieved from 7-hydroxyflavone and α- oxoketene dithioacetals. In the first step 7-hydroxyflavone was regioselectively formylated under Duff reaction conditions. Resulting 8-formyl-7-hydroxy flavones were condensed with α-oxoketene dithioacetals in the presence of a catalytic amount of piperidine to furnish 3-aroylcoumarin-flavone hybrids.
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Radical Cation Salts Induced aza-Diels-Alder Reaction: Synthesis of Hexahydrofuro[3,2-c]- quinoline Derivatives
Authors: Zhong Jia, Yan Ren, Cong-De Huo, Xiang-Ning Chen, Chong-Xiang Tong and Xiao-Dong JiaAza-Diels-Alder reaction between imines and 2,3-dihydrofuran under radical cation induced conditions was achieved and series of hexahydrofuro[3,2-c]quinoline derivatives was prepared. The stereoselectivity was affected by the substituents on imines, which revealed a stepwise mechanism. A radical cation mediated mechanism was proposed to rationalize the formation of the products.
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A Facile Method for the Synthesis of 3-Alkyloxindole
Authors: Tai-Ping Du, Gang-Guo Zhu and Jian ZhouBenzylamine in combination with acetic acid was identified as a powerful catalyst for the condensation of oxindole with aldehydes, acetone or cyclic ketones. A variety of 3-alkyloxindoles could be readily prepared in 10 mmol scale via the sequential benzylamine acetate catalyzed condensation of oxindoles with aldehydes (or ketones) and conjugate reduction by NaBH4.
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Volumes & issues
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Volume 22 (2025)
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Volume 21 (2024)
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Volume 20 (2023)
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Volume 19 (2022)
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Volume 18 (2021)
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Volume 17 (2020)
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Volume 16 (2019)
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Volume 15 (2018)
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Volume 14 (2017)
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Volume 13 (2016)
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Volume 12 (2015)
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Volume 11 (2014)
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Volume 10 (2013)
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Volume 9 (2012)
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Volume 8 (2011)
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Volume 7 (2010)
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Volume 6 (2009)
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Volume 5 (2008)
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Volume 4 (2007)
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Volume 3 (2006)
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Volume 2 (2005)
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Volume 1 (2004)
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