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1.
A straightforward method has been developed for the synthesis of 1-amidomethyl-imidazo[1,2-a]pyridines by Yb(OTf)3 catalyzed three-component reaction of aldehydes, acetamide, and imidazo[1,2-a]pyridines. A series of substituted 3-substituted imidazo[1,2-a]pyridines were synthesized in moderate to good yield (21–74%) under mild reaction condition and the catalyst was recycled for four cycles. 相似文献
2.
A one-pot synthesis of imidazo[1,2-a]pyridines is described. Benzyl halides or benzyl tosylates are oxidized to aldehydes under mild Kornblum conditions which then undergo a three-component reaction with various 2-aminopyridines and isocyanides to afford the imidazo[1,2-a]pyridines in excellent yields. 相似文献
3.
Selvaraj Mohana Roopan Shashikant Malagoud Patil Jeyakannu Palaniraja 《Research on Chemical Intermediates》2016,42(4):2749-2790
Of the biologically important benzene fused heterocycles, the most important are those containing a ring-junction nitrogen. The majority of ring junction systems do not occur naturally, but they have been important from a theoretical viewpoint, for preparation of potentially active analogues. The imidazo[1,2-a] pyridines are an important class of nitrogen ring junction heterocyclic compounds. They have huge applications in medicinal chemistry and drug molecule production. Thus, the initial discussion focuses on synthetic strategies of imidazo[1,2-a] pyridines, and later we disclose the reactivity of the imidazo[1,2-a]pyridines. This review is intended to summarize and discuss the most recent developments of synthesis and reactivity of imidazo[1,2-a]pyridines, mainly the contributions after 2007. 相似文献
4.
A convenient and highly convergent method for the synthesis of new imidazo[1,2-a]pyridine-based coelenterazine analogues is reported. The imidazo[1,2-a]pyridine core was constructed through a condensation between 2-aminopyridine analogues and arylglyoxals. Additionally, a new approach to the synthesis of benzylglyoxals was introduced. The imidazo[1,2-a]pyridines display moderate antioxidant activities at a low micromolar level in 2,2-diphenyl-1-picrylhydrazyl (DPPH). 相似文献
5.
Amanda L. Rousseau Pulane Matlaba Christopher J. Parkinson 《Tetrahedron letters》2007,48(23):4079-4082
The novel use of zinc chloride to catalyze the one-pot, three component synthesis of imidazo[1,2-a]pyridines from a range of substrates using either conventional heating or microwave irradiation is described. This methodology affords a number of imidazo[1,2-a]pyridines in reasonable yields and short reaction times without any significant optimization of the reaction conditions. 相似文献
6.
A convenient halogenation of 2-arylimidazo[1,2-a]pyridines using sodium chloride/bromide/iodide as the halogen sources in the presence of K2S2O8 as an easy-to-handle oxidizing agent was developed. The present work offers an efficient and rapid access to 3-chloro-, 3-bromo- and 3-iodo-2-arylimidazo[1,2-a]pyridines which can be readily converted to C3-substituted imidazo[1,2-a]pyridines by cross-coupling reactions. 相似文献
7.
A novel three-component reaction towards the synthesis of imidazo[1,2a]pyridines was independently developed based on 2-aminopyridines, aldehydes and alkynes, and thereby imidazo[1,2a]pyridines were obtained in acceptable yields by the CuSO4/TsOH catalyzed three-component reaction. 相似文献
8.
A transition-metal-free, visible-light-induced trifluoromethylation of imidazo[1,2-a]pyridines has been developed at mild conditions by employing cheap and commercially available anthraquinone-2-carboxylic acid (AQN-2-CO2H) as the photo-organocatalyst, and Langlois reagent as the trifluoromethylating reagent. A series of 3-(trifluoromethyl)imidazo[1,2-a]pyridine derivatives with broad functionalities could be conveniently and efficiently obtained by direct regioselective functionalization. 相似文献
9.
A facile and environmental friendly protocol for the synthesis of N-bridged fused bicyclic compounds such as imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and imidazo[2,1-b]thiazole, from commercially available starting materials has been developed. The reaction proceeds via NBS mediated in situ formation of α-brominated intermediate of corresponding aromatic ketones, 1,3-diketones, β-keto esters, followed by trapping with suitable nucleophiles to provide these versatile imidazole fused bicyclic heterocycles in good yields under metal-free conditions. 相似文献
10.
Richard J. Sundberg D. J. Dahlhausen G. Manikumar B. Mavunkel Atanu Biswas V. Srinivasan Fred King Philip Waid 《Journal of heterocyclic chemistry》1988,25(1):129-137
A series of substituted 2-aryl imidazo[1,2-a]pyridines has been prepared in which a variety of substituents are introduced on the 4′-position of the phenyl ring and on the 3, 5 , 6 or 7 position of the heterocyclic ring. Most examples have acetamido, bromo, cyano, or formyl substituents at the 4′-position. Analogous imidazo-[2,1-b]fhiazoles and imidazo[1,2-a]pyrimidines have also been prepared. Another series of compounds consisting of 4′-formylphenoxymethyl derivatives of imidazole, the three positional isomers of pyridine, thiazole, benzimidazole and ring-substituted imidazo[1,2-a]pyridines has been prepared. 2-(4′-Formylphenylethenyl) derivatives of imidazole and imidazo[1,2-a]pyridine were also prepared. 相似文献
11.
E. Abignente P. De Caprariis E. Fattorusso L. Mayol 《Journal of heterocyclic chemistry》1989,26(6):1875-1880
The reaction of various heteroarylamines with ethyl 2-benzoyl-2-bromoacetate was used to obtain some imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, imidazo[2,1-b]thiazoles and imidazo[2,1-b]benzothiazoles characterized by the presence of a phenyl moiety on the imidazole ring. In the case of thiazole and benzothiazole derivatives, unexpected by-products were isolated and their structures elucidated. 相似文献
12.
Sougata Santra Shubhanjan MitraAvik Kumar Bagdi Adinath MajeeAlakananda Hajra 《Tetrahedron letters》2014
An efficient, one-pot, three-component domino strategy has been demonstrated for the synthesis of imidazo[1,2-a]pyridines using a catalytic amount of Fe(III) chloride in high yields in air. A library of imidazo[1,2-a]pyridines was synthesized by the reaction of easily available aldehydes and 2-aminopyridines in a mixture of nitroalkane and DMF (2:1). This transformation presumably occurs by a sequential aza-Henry reaction/cyclization/denitration. The use of readily available chemicals as starting materials, inexpensive metal catalyst, aerobic reaction conditions, tolerance of a wide range of functional groups, and operational simplicity are the notable advantages of this present protocol. 相似文献
13.
Richard Ducray Pascal Boutron Hervé Germain Maryannick Lamorlette Mickael Maudet Georges Pasquet Iain Simpson 《Tetrahedron letters》2010,51(36):4755-4701
A two-step synthesis of 3-(2-chloropyrimidin-4-yl)imidazo[1,2-a]pyridines is presented. The late stage elaboration of the imidazopyridine through a cyclocondensation allows a rapid access to a variety of substitution patterns. The intermediate enol ethers were obtained from inexpensive reagents in a ligand-free Heck coupling. This methodology has been extended to the formation of pyrazolo[1,5-a]pyridines via a formal 1,3-dipolar cycloaddition. 相似文献
14.
Abdou O. Abdelhamid Hamdi M. Hassaneen Ahmad S. Shawali Cyril Prknyi 《Journal of heterocyclic chemistry》1983,20(3):639-643
Arylazo derivatives of imidazo[2,1-b]thiazoles, imidazo[1,2-b]pyrazoles, imidazo[1,2-b]-s-triazoles, imidazo[1,2-a]pyrimidines, and imidazo[1,2-a]pyridines were obtained in good yields from α-keto hydrazidoyl halides and 2-aminothiazole, 5-aminopyrazole, 5-aminotriazole, 2-aminopyrimidine, and 2-aminopyridine, respectively (cf. Tables I and II). The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectra, and alternate synthesis wherever possible. 相似文献
15.
Nilesh Mutkule Nageshprasad Bugad Santosh Mokale Vilas Choudhari Milind Ubale 《Journal of heterocyclic chemistry》2020,57(8):3186-3192
This paper describes highly efficient concise method for the synthesis of imidazo[1,2-a] pyridine. It is a first report employing, amino pyridines, copper nitrate, and phenyl acrylic acids in the synthesis of imidazo[1,2-a] pyridine. The silent features of the devised protocol include the high yield, milder reaction conditions, and shorter reaction time. 相似文献
16.
Valeriya G. Melekhina Vitaly S. Mityanov Boris V. Lichitsky Andrey N. Komogortsev Artem N. Fakhrutdinov Elena D. Daeva Michail M. Krayushkin 《Tetrahedron letters》2019,60(26):1745-1747
Ultraviolet irradiation of hydroxyl substituted terarylenes provided a simple, efficient, and environmentally friendly method for the synthesis of imidazo[1,2-a]pyridines. The starting terarylenes were prepared via the one-pot, three-component condensation of readily accessible arylglyoxals, 2-aminopyridines, and dimedone. 相似文献
17.
《Tetrahedron letters》2019,60(31):2070-2073
A series of 11-aryl-11H-indeno[1′,2′:4,5]imidazo[1,2-a]pyridines was obtained via AlCl3-promoted, dehydrative cyclization of the corresponding aryl(2-arylimidazo[1,2-a]pyridin-3-yl)methanols in moderate to good yields. The synthesized compounds can be considered as conformationally restricted, privileged aza-heterocyclic scaffold bearing triarylmethane analogs. 相似文献
18.
Ingrid Rodrigues Angelita M. Barcellos Andrei L. Belladona Juliano A. Roehrs Roberta Cargnelutti Diego Alves Gelson Perin Ricardo F. Schumacher 《Tetrahedron》2018,74(31):4242-4246
Oxone mediated reaction of imidazo[2,1-b]thiazole, imidazo[1,2-a]pyridine and 1H-pyrazole derivatives with diaryl diselenides is presented here. The methodology represents an efficient and simple protocol for carrying out the selective synthesis of 5-arylselanyl-imidazo[2,1-b]thiazoles, 3-arylselanyl-imidazo[1,2-a]pyridines and 4-arylselanyl-1H-pyrazoles in high yields using a stable, nontoxic and cheap oxidant. The reactions were conducted at 60?°C in air using acetonitrile as solvent. Alternatively, the use of ultrasound irradiation is presented as a tool for fast and efficient energy transfer that significantly reduced the reaction time. 相似文献
19.
We achieved efficient synthesis of imidazo- and pyrimido[1,2-b]benzo-1,2,4-thiadiazine-1,1-dioxides by the tandem aza-Wittig reaction/intramolecular NH-nucleophilic addition/NH-nucleophilic substitution cyclization methodology, involving sulfonamide ester-containing carbodiimides as the key intermediates. Similarly, imidazo[2,1-b]quinazolinones, imidazo[1,2-a]pyrimidinediones, and imidazo[1,2-a]imidazolidinediones were also synthesized through the aza-Wittig reaction-tandem cyclization strategy. When homochiral (l)-alanine methyl ester was incorporated as a building block into the corresponding iminophosphorane starting materials, we obtained optically active imidazo[1,2-b]benzo-1,2,4-thiadiazine and imidazo[2,1-b]quinazolinone derivatives without any racemization through the one-pot tandem methodology. 相似文献
20.
Ahmed El Akkaoui Ibtissam Bassoude Jamal Koubachi Sabine Berteina-Raboin Abderrahim MouaddibGérald Guillaumet 《Tetrahedron》2011,67(37):7128-7138
New and efficient regioselective Sonogashira and Suzuki-Miyaura palladium-catalyzed coupling reactions of 3,6-dihalogenoimidazo[1,2-a]pyridines followed by another cross-coupling has been successfully developed. Various solvents, palladium species and bases were tested. Scope and limitations of this regiocontrolled palladium-catalyzed reaction were investigated. The synthesis of 3,6-disubstituted imidazo[1,2-a]pyridine derivatives using one-pot regioselective double-coupling approach was developed. This procedure affords convergent syntheses of polysubstituted compounds in high yields in a very few steps. 相似文献