- Access to 2-pyridinylamide and imidazopyridine from 2-fluoropyridine and amidine hydrochloride
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Under catalyst-free conditions, an efficient method to synthesize 2-pyridinylamides has been developed, and the protocol uses inexpensive and readily available 2-fluoropyridine and amidine derivatives as the starting materials. Simultaneously, the copper-catalysed approach to imidazopyridine derivatives has been established with high chemoselectivity and regiospecificity. The results suggest that the nitrogen-heterocycles containing iodide substituents can also be compatible for the reaction via the cascade Ullmann-type coupling, and the nucleophilic substitution reaction provides the target products in a one-pot manner.
- Chen, Lu,Huang, Shuo,Ji, Xiaoliang,Li, Jiaming,Li, Jian,Li, Yibiao,Liu, Jiasheng,Peng, Shiyong,Zhang, Kun
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supporting information
p. 9292 - 9299
(2020/12/03)
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- Selective exploitation of acetoacetate carbonyl groups using imidazolium based ionic liquids: synthesis of 3-oxo-amides and substituted benzimidazoles
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An unprecedented Br?nsted base ionic liquid tuned selective aminolysis of ester carbonyl of acetoacetates is demonstrated to achieve acetoacetamide derivatives. Other imidazolium ionic liquid performs an efficient cyclization catalysis involving acetoacetate-carbonyl groups and o-phenylenediamine at elevated temperature to produce benzimidazoles via C–C bond cleavage of intermediate 1,5-benzodiazepinones under solvent-free conditions.
- Chakraborty, Ankita,Majumdar, Swapan,Maiti, Dilip K.
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p. 3298 - 3302
(2016/07/11)
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- Gadolinium (III) chloride catalyzed facile synthesis of 2-substituted benzimidazoles under solvent-free conditions
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A series of 2-substituted benzimidazoles have been prepared from o-diamines and 1,3-dicarbonyl compounds using Gadolinium chloride as a catalyst under solvent free condition in good yields. Gadolinium chloride has been demonstrated as a mild and efficient catalyst.
- Sathaiah,Venkat Lingaiah,Chandra Shekhar,Ravi Kumar,Raju,Shanthan Rao
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p. 953 - 957
(2015/08/19)
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- Studies on in vitro antimycobacterial activities of some 2-substitutedimidazo[4,5-b] and [4,5-c]pyridine derivatives
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In this study, 2-substitutedimidazo[4,5-b]pyridine and 2-substitutedimidazo[ 4,5-c]pyridine which have -CH2OH, -CH2Cl, -CH3 or -C2H5 groups in positions 2 have been synthesized and tested for their in vitro antimycobacterial activity against M. tuberculosis H37Rv strains. The compounds were synthesized by previously reported methods. 2-Chloromethylimidazo[4,5-b]pyridine and 2-methylimidazo[4,5-c]pyridine were found to be more active than the other compounds tested.
- ?zelik, Azime Berna,ülger, Mahmut,Aslan, G?nül,Emekda, Gürol,?zden, Tuncel
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- An efficient one-pot synthesis of condensed imidazoles using pentafluorophenylammonium triflate as novel, metal-free and reusable catalyst
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A superior method of synthesis of condensed imidazoles by the catalytic action of pentafluorophenylammonium triflate on the reaction of 1,2-diaminoaromatics with orthoesters is described. The catalyst is reusable and can be applied several times without considerable decrease in the yields and rates of the reaction.
- Montazeri, Naser,Esmaeili, Abbas
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p. 3446 - 3448
(2013/05/21)
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- Novel strategy for synthesis of substituted benzimidazo[1,2-a]quinolines
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An efficient method for the synthesis of benzimidazo[1,2-a]quinolines under transition-metal-free conditions has been developed through a cascade reaction involving sequential aromatic nucleophilic substitution and intramolecular Knoevenagel condensation reactions. This method is applicable for the synthesis of a wide range of benzimidazo[1,2-a]quinoline derivatives from readily available 2-fluoroarylaldehyde and benzimidazole substrates.
- Kato, Jun-Ya,Ito, Yutaro,Ijuin, Ryosuke,Aoyama, Hiroshi,Yokomatsu, Tsutomu
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supporting information
p. 3794 - 3797
(2013/08/23)
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- Lithium bromide catalyzed solvent free method for synthesis of 2-substituted benzimidazoles and imidazopyridines
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The first successful lithium bromide mediated solvent free condensation of arylenediamine and esters to obtain 2-substituted benzimidazole and imidazopyridine in good to excellent yields is described.
- Dekhane, Deepak V.,Pawar, Shivaji S.,Gupta, Sunil V.,Shingare, Murlidhar S.,Thore, Shivaji N.
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experimental part
p. 519 - 523
(2011/01/13)
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- Rapid synthesis of imidazo[4,5-b]pyridine containing polycyclics by means of palladium-catalyzed amidation of 2-chloro-3-nitropyridine
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Regioselective nucleophilic substitution of 2-chloro 3-nitropyridine with heterocyclic amides under Pd-catalyzed reaction conditions as described by Buchwald yielded imidazo [4,5-b] pyridine-containing polycyclics as novel scaffolds.
- Salomé, Christophe,Schmitt, Martine,Bourguignon, Jean-Jacques
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supporting information; experimental part
p. 3798 - 3800
(2009/10/11)
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- Regioselective N-alkylation of imidazo[4,5-b]pyridine-4-oxide derivatives: an experimental and DFT study
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Regioselectivities were determined for N-alkylations of imidazo[4,5-b]pyridine-4-oxide and 2-methyl-imidazo[4,5-b]pyridine-4-oxide with benzyl bromide or benzyl iodide at RT using K2CO3 in DMF as a base. Experimental attempts have shown that N-1/N-3 ratios slightly varied according to the substitution on C-2 position. This was confirmed by DFT calculations in solvent phase. This computational study has shown first that this N-benzylation reaction passed through a SN2 mechanism. Moreover, regioselectivity of N-benzylation has appeared essentially governed by 'steric approach control'. It explained that opposite N-1/N-3 ratios were obtained with imidazo[4,5-b]pyridine-4-oxide and its 2-methyl-substituted analog. Finally, regioselectivities slightly varied with the nature of benzyl halide.
- Zeinyeh, Wael,Pilmé, Julien,Radix, Sylvie,Walchshofer, Nadia
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scheme or table
p. 1828 - 1833
(2009/07/17)
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- SMALL MOLECULE INHIBITORS OF PLASMODIUM FALCIPARUM DIHYDROOROTATE DEHYDROGENASE
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Inhibitors of dihydroorotate dehydrogenase (DHODH) for the Plasmodium enzyme have been identified and characterized. The inhibitors have high specificity, submicromolar efficacy against cultured parasite strains, exhibit drug-like properties, and are not overtly cytotoxic.
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Page/Page column 39-40
(2010/01/29)
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- Zeolite-induced heterocyclization: A superior method of synthesis of condensed imidazoles
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A superior method of synthesis of condensed imidazoles by the catalytic action of H-Y zeolite on the reaction of 1,2-diaminoaromatics with orthoesters is described.
- Heravi,Montazeri,Rahmizadeh,Bakavoli,Ghassemzadeh
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p. 584 - 585
(2007/10/03)
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- Etude de la reaction de l'acetylacetone avec les diamines heteroaromatiques
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The influence of the starting o-diamine on the reaction products is shown in the condensation of heteroaromatic o-diamines with acetylacetone; 2,3- and 3,4-diaminopyridines gave only a crotonic intermediate providing imidazopyridines.On the other hand, 1,
- Essassi, E. M.,Zniber, R.,Bernardini, A.,Viallefont, Ph.
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p. 1015 - 1018
(2007/10/02)
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- Heterocyclisation via Selective Elimination: Reaction of 2,3-Diaminopyridine with Acyclic Ketones under Thermal Conditions
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Reactions of 2,3-diaminopyridine and its 5-bromo analogue with three symmetrical and nine unsymmetrical acyclic ketones under thermal conditions have been studied.The reactions have yielded 2-substituted-1H-imidazopyridines by the elimination of one of the C2-substituents from the probable, though unisolated, intermediates 2,2-disubstituted-2,3-dihydro-1H-imidazopyridine derivatives.Elimination of one of the groups in the case of symmetrical ketones and preferentially of benzyl group in the case of benzyl methyl ketone has been observed.All the three alkyl phenyl ketones studied afford 2-phenylimidazopyridine by the selective loss of the alkyl group.Elimination of branched alkyl group has been noticed in the reactions involving methyl t-butyl and methyl i-propyl ketones, while the preferential elimination of methyl group is observed in the case of methyl n-alkyl ketones.Suitable explanations have been offered for the observed selective eliminations.
- Dubey, Pramod Kumar,Ratnam, C. V.
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p. 863 - 865
(2007/10/02)
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