共查询到20条相似文献,搜索用时 15 毫秒
1.
Metal-free synthesis of substituted imidazole [1,2-a]pyridines from deprotective N-(prop-2-yn-1-yl)pyridin-2-amines in water is elucidated. Electron releasing substituents on pyridine ring provided pure products in quantitative yields without separation by column chromatography. 相似文献
2.
Vincent Gaumet Emmanuel Moreau Abbass Taleb Johan Neyts Claire Lartigue Olivier Chavignon Alain Gueiffier Jacques Métin 《Tetrahedron letters》2010,51(47):6082-6085
Access to N-protected or N-free imidazo[1,2-a]pyrrolo[3,2-c]pyridine derivatives as potential antiviral compounds was achieved in good yields from N-protected 7-amino-8-halo-2-methylimidazo[1,2-a]pyridines by catalytic coupling of terminal acetylenes under mild conditions using [PdCl2(PPh3)2] or [Cu(Phen)(PPh3)2]NO3. 相似文献
3.
N-Arylidene-2-aryl-imidazo[1,2-a]azin-3-amines were synthesized via a one-pot, four-component condensation reaction using a 2-aminoazine, toluene-4-sulfonylmethyl isocyanide (TsCH2NC), and two equivalents of readily available aromatic aldehydes. The reaction was performed in diethyl ether as the solvent, with p-toluenesulfonic acid (p-TSA) as the catalyst at reflux temperature. 相似文献
4.
Alexander S. Kiselyov 《Tetrahedron letters》2006,47(17):2941-2944
A series of 5,7,8-polysubstituted imidazo[1,2-a]pyridines were synthesized regioselectively from in situ generated α,β-unsaturated imines and dianions derived from methyl azolyl acetates in a one-pot procedure. The targeted molecules were conveniently isolated in analytically pure form (ca. 50-70% yields) by trituration of the concentrated reaction mixtures with cold ether. 相似文献
5.
B.V. Subba Reddy P. Sivaramakrishna ReddyY. Jayasudhan Reddy J.S. Yadav 《Tetrahedron letters》2011,52(44):5789-5793
Indium(III) bromide has been used for the first time for the synthesis of imidazo[1,2-a]pyridines in a one-pot operation from 2-aminopyridine, aldehydes, and alkynes. InBr3 was found to be more effective for the activation of both alkyne and imine derived from aryl aldehyde and 2-aminopyridine. 相似文献
6.
Maxime D. Crozet 《Tetrahedron letters》2006,47(39):7061-7065
A new simple, rapid and high yielding synthesis of various 6-aryl-2-arylsulfonylmethyl-3-nitroimidazo[1,2-a]pyridines by Suzuki cross-coupling reaction is described using microwave irradiation in aqueous medium without organic co-solvent in the presence of tetrabutylammonium bromide. 相似文献
7.
Several imidazo and pyrimido[1,2-a]pyrimidinones of type 1 and 2 were synthesized through intramolecular cyclization of pyrimidines 9 or pyrimidinones 10 bearing a variety of β and γ-aminoalcohols at the 2-position. Ring closure of the pyrimidinones of type 10 under Mitsunobu conditions lead to mixtures of both bicyclic regioisomers 1 and 2. Treatment of pyrimidines of type 9 with H2SO4 provided an efficient and operationally simple one-pot hydrolysis-cyclization procedure for obtaining imidazo and pyrimido[1,2-a]pyrimidinones 1 in good yields as the sole regioisomeric bicyclic product. 相似文献
8.
The chromeno-imidazo[1,2-a]pyridine scaffold was generated in an one pot condensation/cyclization reaction involving a salicylaldehyde and 1-(cyanomethyl)pyridinium chloride, in aqueous sodium carbonate solution. These novel compounds were isolated in 47-71% yield. The reaction pathway was followed by 1H NMR spectroscopy allowing a clear understanding of the side reactions involved in the process.Different mono-substituted pyridinium chlorides were synthesized and reacted with mono-substituted salicylaldehydes and a detailed discussion of the scope of the synthetic method is also presented. 相似文献
9.
A facile method for direct Pd(OAc)2-catalyzed oxidative cross-coupling of unactivated imidazo[1,2-a]pyridine with simple arenes has been developed. The reaction shows good reaction efficiency, high regioselectivity, and good functional-group compatibility. This approach provides a useful protocol for the preparation of imidazo[1,2-a]pyridine–arene structure of interest in biological and pharmaceutical materials. 相似文献
10.
Fumitoshi Shibahara 《Tetrahedron》2009,65(26):5062-12876
The halogenation of 3-arylimidazo[1,5-a]pyridines was carried out with iodine, bromine, N-chlorosuccinimide, and 1-fluoro-2,4,6-trimethylpyridinium tetrafluoroborate as halogenating agents to give selectively halogenated products 1-halo-3-arylimidazo[1,5-a]pyridines in good to excellent yields. Kumada-Tamao-Corriu cross-coupling of the obtained 1-iodo-3-arylimidazo[1,5-a]pyridines and aryl Grignard reagents led to 1,3-diarylated imidazo[1,5-a]pyridines in good to excellent yields. Suzuki-Miyaura cross-coupling of the 1-bromo-3-phenylimidazo[1,5-a]pyridine and p- or m-methoxycarbonylphenylboronic acids furnished the coupling product in respective yields of 91% and 61%. The obtained 1,3-diarylated imidazo[1,5-a]pyridines showed a wide variety of fluorescent emissions in a wavelength range of 449-533 nm with improved quantum yields compared to monoarylated ones. 相似文献
11.
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
12.
Alternative strategies for functionalizing 2-chloro-3-nitroimidazo[1,2-a]pyridine have been developed. Suzuki–Miyaura cross-coupling reaction provided easily the corresponding 2-arylated compounds, and herefrom the nitro group was reduced into amine which afforded amides, anilines, and ureas in the 3-position. The amination of the key compound using a metal-catalyzed reaction was reported. This study highlighted the importance of the nitro group to facilitate the chlorine displacement. Other nucleophilic aromatic substitutions open a route to various products derived from imidazo[1,2-a]pyridine. 相似文献
13.
Ahmad Shaabani Fahimeh Rezazadeh Ebrahim Soleimani 《Monatshefte für Chemie / Chemical Monthly》2008,139(8):931-933
Ammonium chloride as a very inexpensive and readily available reagent efficiently catalyzes one-pot, three-component Groebke condensation reactions of aldehydes, isocyanides, and 2-aminopyridines or 2-aminopyrimidines in methanol to afford the corresponding
imidazo[1,2-a]pyridines in high yields at room temperature.
Correspondence: Ahmad Shaabani, Department of Chemistry, Shahid Beheshti University, PO Box 19396-4716, Tehran, Iran. 相似文献
14.
3-Aminoimidazo[1,2-a]pyridines have been synthesized in good to excellent yields in the presence of the ionic liquid 1-butyl-3-methylimidazolium bromide [bmim]Br, the reaction workup is simple and the ionic liquid can be easily separated from the product and reused. 相似文献
15.
We have described a convenient regioselective one-pot approach to pyrazolo[1,5-a]- and imidazo[1,2-a]pyrimidine derivatives from α,β-unsaturated imines generated in situ and amino heterocycles. Reaction is general with respect to all three components, namely (i) nitrile, (ii) aldehyde, and (iii) amino heterocycle reagents. Good yields (52-77%), convenient isolation of the targeted molecules are the distinct characteristics of the developed protocol. 相似文献
16.
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
17.
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
18.
A new, one-pot and three-component synthesis of 4H-pyrido[1,2-a]pyrimidines, 4H-pyrimido[1,2-a]pyrimidines, and 4H-pyrazino[1,2-a]pyrimidines is described. The reactive 1:1 zwitterionic intermediate, formed by the addition of isocyanides to dialkyl acetylenedicarboxylates, was trapped by N-(2-heteroaryl)amides to yield a ketenimine intermediate, which was cyclized and then rearranged under the reaction conditions to afford the title compounds under mild reaction conditions in good yields. Single-crystal X-ray analysis conclusively confirms the structure of the obtained bridgehead bicyclic 6-6 heterocyclic compounds. 相似文献
19.
J.S. Yadav B.V. Subba Reddy Y. Gopal Rao M. Srinivas A.V. Narsaiah 《Tetrahedron letters》2007,48(43):7717-7720
α-Diazoketones undergo smooth coupling with 2-aminopyridines in the presence of 10 mol % of copper(II) triflate to produce the corresponding 2-substituted imidazo[1,2-a]pyridines (IPs) in excellent yields with high selectivity. Rh2(OAc)4 is also found to be an equally effective catalyst for this transformation. 相似文献
20.
Mounir Andaloussi Emmanuel Moreau Olivier Chavignon Jean C. Teulade 《Tetrahedron letters》2007,48(47):8392-8395
Two new imidazo[1,2-a]pyridine derivatives, pyridinoimidazo[1,2-a]pyridine (10) and pyrroloimidazo[1,2-a]pyridine (16), were synthesised from 2-amino-4-methyl-5-nitropyridine (1) by linear cyclisation, making use of dimethylformamide dimethylacetal (DMFDMA) as an agent of vinylamine functionalisation. This report describes first the formation of pyridine and pyrroloimidazopyridine from (1), and then the formation of pyridine-fused and pyrrolo-fused pyridine by the Friedländer method and reductive cyclisation followed by treatment of the resulting adduct with chloroacetaldehyde. 相似文献