- Oxidation Potential-Guided Electrochemical Radical-Radical Cross-Coupling Approaches to 3-Sulfonylated Imidazopyridines and Indolizines
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Oxidation potential-guided electrochemical radical-radical cross-coupling reactions between N-heteroarenes and sodium sulfinates have been established. Thus, simple cyclic voltammetry measurement of substrates predicts the likelihood of successful radical-radical coupling reactions, allowing the simple and direct synthetic access to 3-sulfonylated imidazopyridines and indolizines. The developed electrochemical radical-radical cross-coupling reactions to sulfonylated N-heteroarenes boast the green synthetic nature of the reactions that are oxidant- and metal-free.
- Kim, Wansoo,Kim, Hun Young,Oh, Kyungsoo
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p. 15973 - 15991
(2021/07/26)
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- Solvent and catalyst-free synthesis of imidazo[1,2-a]pyridines by grindstone chemistry
-
The present work describes the solvent and catalyst-free synthesis of imidazo[1,2-a]pyridines in excellent to nearly quantitative yields from 2-aminopyridines and a wide variety of ω-bromomethylketones using a grindstone procedure at 25°C to 30°C for 3 to
- Godugu, Kumar,Nallagondu, Chinna Gangi Reddy
-
p. 250 - 259
(2020/10/23)
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- Regioselective C-H dithiocarbamation of indolizines with tetraalkylthiuram disulfide under metal-free conditions
-
An efficient and straightforward metal-free regioselective C-H dithiocarbamation of indolizines with tetraalkylthiuram disulfide has been described. A series of indolizine-dithiocarbamate derivatives were easily accessed in moderate to good yields with a broad scope. In addition, imidazo[1,2-a]pyridines were also well tolerated to afford diverse imidazoheterocycle-dithiocarbamate products, which are expected to be utilized for drug discovery. Of note, the reaction could be readily scaled up, and shows its practical value in organic synthesis.
- Cao, Hua,Lin, Jiatong,Liu, Xiang,Song, Dan,Zhan, Haiying,Zhang, Zemin,Zhuang, Canzhan
-
supporting information
p. 5284 - 5288
(2021/06/28)
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- Metal-free oxidative decarbonylative halogenation of fused imidazoles
-
An efficient strategy has been developed for the deformylative halogenation of carbaldehyde imidazo-fused heterocycles in the presence of TBHP controlled by temperature. A convenient and sequential functionalization (C8 to C3) portrays the synthetic utility of the current method.N-Heterocycle benzamide products were also observedviathe ring opening of imidazopyridines through the cleavage of C-C bond at high temperatures. Features of this method include temperature-controlled excellent regioselectivity, mild conditions and functional group tolerance.
- Kumar, Gulshan,Shankar, Ravi,Singh, Davinder,Tali, Javeed Ahmad
-
supporting information
p. 20551 - 20555
(2021/11/23)
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- CuCl2-catalyzed N[sbnd]O bond cleavage of oxime esters: Approach to imidazoheterocycles and furo[3,2-c]chromenyl fused imidazoles
-
An articulate approach to a diverse set of imidazoheterocycles in good to high yields via a copper-catalyzed aza-annulation of several oxime esters with a group of 2-amino-azaarenes was developed. The above cyclization reaction probably proceeds via a single electron transfer process which embodies a new technique for creating two new C[sbnd]N bonds for imidazole ring synthesis. Gratifyingly, the implementation of this chemistry could be further stretched to the synthesis of a novel class of fused imidazoles bearing a furo[3,2-c]chromene moiety via a sequential C[sbnd]N bond formation, followed by C(sp2)-H functionalization/5-endo-dig-oxacyclization (C[sbnd]C and C[sbnd]O bonds) of in situ produced fused imidazoles with cyclic enynones in the presence of copper(II) as a π-electrophilic Lewis acid catalyst.
- Gudimella, Santosh K.,Kaur, Amanpreet,Kumar, Ram,Samanta, Sampak
-
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- Multicomponent Synthesis of Imidazo[1,2- a]pyridines: Aerobic Oxidative Formation of C-N and C-S Bonds by Flavin-Iodine-Coupled Organocatalysis
-
Herein, we report an aerobic oxidative C-N bond-forming process that enables the facile synthesis of imidazo[1,2-a]pyridines and takes advantage of a coupled organocatalytic system that uses flavin and iodine. Furthermore, the dual catalytic system can be applied to the one-pot, three-step synthesis of 3-thioimidazo[1,2-a]pyridines from aminopyridines, ketones, and thiols.
- Okai, Hayaki,Tanimoto, Kazumasa,Ohkado, Ryoma,Iida, Hiroki
-
supporting information
p. 8002 - 8006
(2020/11/02)
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- Imidazopyridine compound, pharmaceutical composition containing the same, and preparation method and application thereof (by machine translation)
-
Specifically discloses a pharmaceutical composition containing the compound and a pharmaceutically acceptable salt or a pharmaceutically acceptable solvate [1,2 - a] of the compound, and the preparation method, comprises the following steps of inhibiting, protein selectivity, drug effect strong STAT3 patent medicine, safety and the like, and the like . is particularly suitable for preventing and, or treating tumor growth and metastasis as well as pharmaceutical composition and pharmaceutical acceptable salt or pharmaceutically acceptable salt or pharmaceutically acceptable solvate of the compound in preparing STAT3 high-expression cell abnormal proliferation, form change and exercise function hyperthyroidism, and other related diseases / and are disclosed in the present invention. (by machine translation)
- -
-
Paragraph 0062-0066; 0095-0099
(2020/05/01)
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- PhI(OAc)2-mediated oxidative C[sbnd]H sulfoximination of imidazopyridines under mild conditions
-
A facile protocol for direct oxidative C[sbnd]N bond coupling of unactivated imidazo[1,2-a]pyridines with NH-sulfoximines was disclosed using sulfoximines as the nitrogen sources in the presence of (diacetoxy)iodobenzene (PhI(OAc)2). The reacti
- Luan, Nannan,Liu, Zhenwei,Han, Shuaijun,Shen, Linhua,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
-
supporting information
(2019/11/26)
-
- Unconventional Reactivity with DABCO-Bis(sulfur dioxide): C–H Bond Sulfenylation of Imidazopyridines
-
This work highlights the unexpected and unprecedented outcome of the reactivity with DABCO-bis(sulfur dioxide). The use of this reagent led to the exclusive introduction of a sulfur atom on the C-3 position of imidazopyridines instead of a sulfone group.
- Le Bescont, Julie,Breton-Patient, Chloé,Piguel, Sandrine
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p. 2101 - 2109
(2020/04/07)
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- Metal-Free Regioselective Alkylation of Imidazo[1,2- a ]pyridines with N -Hydroxyphthalimide Esters under Organic Photoredox Catalysis
-
A visible-light-induced direct C-H alkylation of imidazo[1,2- a ]pyridines has been developed. It proceeds at room temperature by employing inexpensive Eosin Y as a photocatalyst and alkyl N -hydroxyphthalimide (NHP) esters as alkylation reagents. A varie
- Jin, Can,Sun, Bin,Xu, Min,Xu, Tengwei,Yang, Jin,Zhang, Liang,Zhu, Rui
-
supporting information
p. 363 - 368
(2020/02/27)
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- One-pot NBS-promoted synthesis of imidazoles and thiazoles from ethylarenes in water
-
A facile and eco-friendly method has been developed for the synthesis of imidazoles and thiazoles from ethylarenes in water. The reaction proceeds via in situ formation of α-bromoketone using NBS as a bromine source as well as an oxidant, followed by trapping with suitable nucleophiles to provide the corresponding products in good yields under metal-free conditions.
- Chen, Liang,Zhu, Huajian,Wang, Jiang,Liu, Hong
-
-
- Electrochemically initiated intermolecular C-N formation/cyclization of ketones with 2-aminopyridines: An efficient method for the synthesis of imidazo[1,2-: A] pyridines
-
Electrochemical intermolecular C-N formation/cyclization of ketones with 2-aminopyridines using catalytic hydriodic acid as the redox mediator was developed, providing imidazo[1,2-a]pyridines under more environmentally benign conditions. The reaction proceeds in a simple undivided cell, using low toxic ethanol as the solvent, without external oxidants, and exhibits high atom economy. A variety of ketones including acetophenones, unsatruated and alkyl ketones are amenable to this reaction, affording the corresponding products in moderate to excellent yields. A three-component tandem reaction realizing C-N, C-S/C-Se bond formation can also be achieved under standard conditions.
- Feng, Mei-Lin,Li, Shu-Qi,He, Hui-Zi,Xi, Long-Yi,Chen, Shan-Yong,Yu, Xiao-Qi
-
supporting information
p. 1619 - 1624
(2019/04/08)
-
- Novel one step synthesis of imidazo[1,2-a]pyridines and Zolimidine via iron/iodine-catalyzed Ortoleva-King type protocol
-
Imidazo[1,2-a]pyridines form versatile scaffolds in pharmaceutical industry arising from their diverse biological activities. The synthesis of these molecules thus has been of great interest and resulted in the development of a large number of new methodologies. Herein we describe the first iron-catalyzed Ortoleva-King type protocol towards the synthesis of these fused heterocyclic compounds. This methodology employs cheap and easily available FeCl3·6H2O and molecular iodine as the catalytic system. The procedure has been well explored by extending the substrate scope with a variety of aromatic ketones and 2-aminopyridines to furnish different imidazo[1,2-a]pyridine derivatives in moderate to good yields. A successful application of this protocol was also demonstrated by achieving direct one step synthesis of the gastro protective drug, Zolimidine.
- Ujwaldev, Sankuviruthiyil Mohanan,Rohit,Harry, Nissy Ann,Anilkumar, Gopinathan
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- Electrochemical oxidative selenylation of imidazo[1,2–a]pyridines with diselenides
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Electrochemical oxidative selenylation of imidazo[1,2–a]pyridines has been developed. The reaction proceeds in an undivided electrochemical cell equipped with glassy carbon electrodes employing LiClO4 as a supporting electrolyte. This approach
- Kim, Yeon Joo,Kim, Dae Young
-
supporting information
p. 739 - 742
(2019/02/09)
-
- Exogenous-oxidant-free electrochemical oxidative C-H phosphonylation with hydrogen evolution
-
We herein report a versatile and environmentally friendly electrochemical oxidative C-H phosphonylation protocol. This protocol features a broad substrate scope; not only C(sp2)-H phosphonylation, but also C(sp3)-H phosphonylation is tolerated well under exogenous-oxidant-free and metal catalyst-free electrochemical oxidation conditions.
- Yuan, Yong,Qiao, Jin,Cao, Yangmin,Tang, Jingmei,Wang, Mengqin,Ke, Guojuan,Lu, Yichen,Liu, Xue,Lei, Aiwen
-
supporting information
p. 4230 - 4233
(2019/04/30)
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- Iodine mediated oxidative cross coupling of 2-aminopyridine and aromatic terminal alkyne: A practical route to imidazo[1,2-: A] pyridine derivatives
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A novel, transition-metal free route leading to imidazo[1,2-a]pyridine derivatives via iodine mediated oxidative coupling between 2-aminopyridine and aromatic terminal alkyne has been demonstrated. This newly developed method discloses an operationally simple way for the construction of imidazoheterocycles. Commercially available antiulcer drug zolimidine may readily be synthesized employing this method.
- Samanta, Surya Kanta,Bera, Mrinal K.
-
p. 6441 - 6449
(2019/07/10)
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- Rhodium(II)-Catalyzed Regioselective C3-Alkylation of 2-Arylimidazo[1,2-a]pyridines with Aryl Diazoesters
-
A regioselective C3-alkylation based on the reaction of 2-arylimidazo[1,2-a]pyridines with a wide range of aryl α-diazoesters in the presence of a Rh(II) catalyst in dichloroethane at room temperature was developed. This method could be applied in the synthesis of benzoimidazoquinolizinone and cycloheptaimidazopyridinone, which are novel heterocyclic scaffolds. (Figure presented.).
- Kim, Hyunseok,Byeon, Minhyeon,Jeong, Eunchong,Baek, Yonghyeon,Jeong, Seung Jin,Um, Kyusik,Han, Sang Hoon,Han, Gi Uk,Ko, Gi Hoon,Maeng, Chanyoung,Son, Jeong-Yu,Kim, Dongwook,Kim, Sung Hong,Lee, Kooyeon,Lee, Phil Ho
-
supporting information
p. 2094 - 2106
(2019/03/21)
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- Transition-Metal-Free Direct Trifluoromethylation and Perfluoroalkylation of Imidazopyridines under Mild Conditions
-
The first transition-metal-free method for direct C?H trifluoromethylation of imidazo[1,2-a]pyridine derivatives with readily available Ruppert-Prakash reagent TMSCF3 under mild conditions was described. Moreover, this method could be applied to direct C?H perfluoroalkylation of imidazopyridines, affording a series of novel perfluoroalkylated products in moderate to good yields. Notable advantages of this protocol include easy operation, high-efficiency and wide substrate scope. (Figure presented.).
- Han, Shuaijun,Gao, Xianying,Wu, Qingsong,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
-
supporting information
p. 1559 - 1563
(2019/02/19)
-
- Electrochemical oxidative C-H/N-H cross-coupling for C-N bond formation with hydrogen evolution
-
Under metal catalyst-free and exogenous-oxidant-free conditions, a series of C-3 aminated imidazo[1,2-a]pyridines were synthesized by electrochemical intermolecular oxidative C-H/N-H cross-coupling. Furthermore, by using a catalytic amount of ferrocene as
- Yu, Yi,Yuan, Yong,Liu, Huilin,He, Min,Yang, Mingzhu,Liu, Pan,Yu, Banying,Dong, Xuanchi,Lei, Aiwen
-
supporting information
p. 1809 - 1812
(2019/02/12)
-
- Rapid Construction of Fused Heteropolycyclic Aromatics via Palladium-Catalyzed Domino Arylations of Imidazopyridine Derivatives
-
By using diaryliodonium salts, a novel approach of a palladium-catalyzed cascade of diarylation/intramolecular dehydrogenative coupling reaction has been developed in the synthesis of phenanthro-imidazopyridine fused heteropolycycles. The method can toler
- Xue, Chenwei,Han, Jianwei,Zhao, Min,Wang, Limin
-
supporting information
p. 4402 - 4406
(2019/05/08)
-
- Formation of Methylene Linkage for N-Heterocycles: Sequential C-H and C-O Bond Functionalization of Methanol with Cosolvent Water
-
An iron-catalyzed methylene forming strategy is disclosed through sequential C-H and C-O bond functionalization of methanol with cosolvent water. This protocol provides an easy and novel access to methylene-tethered imidazo[1,2-a]pyridine and 2-aminopyridine analogues in a sustainable manner and represents a complementary approach to traditional methylene forming strategies.
- Li, Na,Bai, Jinku,Zheng, Xiaolin,Rao, Honghua
-
p. 6928 - 6939
(2019/06/14)
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- Method for synthesizing 2-arylimidazo[1, 2-a]pyridine compound
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The invention discloses a method for synthesizing a 2-arylimidazo[1, 2-a]pyridine compound and belongs to the technical field of organic synthesis. The method comprises that an ethylbenzene compound,dibromohydantoin DBH and t-butyl hydroperoxide TBHP are added into water and undergo a reaction at 60 DEG C, an inorganic base and an alpha-aminopyridine compound are added into the reaction product and the mixture undergoes a reaction at 80 DEG C to produce a desired product 2-arylimidazo[1, 2-a]pyridine compound. The 2-arylimidazo[1, 2-a]pyridine compound is synthesized from the ethylbenzene compound which is cheaper and more readily available than the 2-arylimidazo[1, 2-a]pyridine compounds such as 2-bromoacetophenone commonly used in the industry.
- -
-
Paragraph 0028; 0029; 0030; 0031
(2018/11/27)
-
- Method for synthesizing 2-arylimidazo[1, 2-a]pyridine compounds from ethylbenzene compounds
-
The invention discloses a method for synthesizing 2-arylimidazo[1, 2-a]pyridine compounds from ethylbenzene compounds and belongs to the field of 2-arylimidazo[1, 2-a]pyridine derivative synthesis. The method comprises that an ethylbenzene compound, a phase transfer catalyst, N-bromosuccinimide NBS and AIBN are added into water, the solution undergoes a reaction at 60 DEG C, an inorganic base andan alpha-aminopyridine compound are added into the reaction product, and the mixture undergoes a reaction at 80 DEG C to produce the 2-arylimidazo[1, 2-a]pyridine compound. The method creatively utilizes the ethylbenzene compound to synthesize the 2-arylimidazo[1, 2-a]pyridine compound. Compared with the 2-bromoacetophenone commonly used as a 2-arylimidazo[1, 2-a]pyridine compound synthesis raw material in the industry, the ethylbenzene compound is cheaper and more easily available.
- -
-
Paragraph 0030; 0031; 0032; 0033
(2018/11/27)
-
- Facile synthesis of imidazo[1,2-a]pyridines promoted by room-temperature ionic liquids under ultrasound irradiation
-
Abstract: A simple and efficient procedure for the synthesis of substituted imidazo[1,2-a]pyridines under ultrasound irradiation has been developed. The reactions were carried out using ionic liquids as catalyst. The reaction procedure demonstrated a broad substrate scope for both acetophenones and 2-aminopyridines, and provided convenient access to a wide variety of imidazo[1,2-a]pyridines. The present method offers several advantages compared to traditional heating methods such as higher yields, shorter reaction times, milder reaction conditions, and easier work-up procedure. Graphical abstract: [Figure not available: see fulltext.].
- Paengphua, Piyawat,Chancharunee, Sirirat
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p. 1835 - 1840
(2018/09/10)
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- Method for synthesizing novel imidazole pyranone compounds containing chalcogens
-
The invention discloses a method for synthesizing novel imidazole pyranone compounds containing chalcogens. The method comprises the steps as follows: firstly, 4-hydroxycoumarin compounds and triflicanhydride react, and 4-triflate-based coumarins are gene
- -
-
Paragraph 0188; 0190
(2018/04/02)
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- Au-catalyzed domino process synthesis of imidazo[1,2-a]pyridines from 2-aminopyridine and N-tosylhydrazones: An efficient C[sbnd]N bond formation reaction
-
A novel Au-catalyzed domino reaction for the synthesis of imidazo[1,2-a]pyridines from 2-aminopyridine and N-tosylhydrazones has been developed using molecular oxygen. It represents a new strategy for the formation of C[sbnd]N bonds. This transformation demonstrated a broad tolerance toward the substrates and allowed the generation of a diverse imidazo[1,2-a]pyridine derivatives with good yields.
- Guo, Pengfeng,Huang, Shuyu,Mo, Jiaxian,Chen, Xiaoyan,Jiang, Hangqi,Chen, Weifeng,Cai, Hehuan,Zhan, Haiying
-
-
- Synthesis and characterization of Imidazo [1,2-a]pyridines and Zolimidine
-
A convenient and efficient synthesis, without any organic solvent or catalyst is described for the preparation of imidazo [1,2-a] pyridine derivatives. The reaction has been done between 2-aminopyridines and α-bromoacetone derivatives in good to excellent yields in water. In several cases the isolation does not require any chromatography for purification. The reaction thus developed has been applied for quick synthesis of zolimidine with 91 % yield.
- Kushwaha, Narva Deshwar,Mondal, Somnath,Sharma, Renu,Kumar, Naresh
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p. 1495 - 1498
(2017/05/29)
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- Iron-Catalyzed Dehydrogenative sp3-sp2 Coupling via Direct Oxidative C-H Activation of Acetonitrile
-
An iron-catalyzed dehydrogenative sp3-sp2 coupling of acetonitrile and 2-arylimidazo[1,2-a]pyridine has been realized, which can serve as a novel approach toward heteroarylacetonitriles. The merit of this strategy is illustrated by the breadth of functional groups tolerated in the transformation and the fast access to pharmaceuticals (such as zolpidem) directly from the heteroarylacetonitriles.
- Su, Huimin,Wang, Luyao,Rao, Honghua,Xu, Hao
-
supporting information
p. 2226 - 2229
(2017/05/12)
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- One pot synthesis of substituted imidazopyridines and thiazoles from styrenes in water assisted by NBS
-
Heating of commercially available styrenes with NBS in water followed by reaction with 2-aminopyridines or thioamides afforded important heterocyclic scaffolds in a one pot procedure. The reaction proceeds via co-oxidant free, in situ formation of α-bromoketone using NBS as a bromine source as well as an oxidant followed by trapping with suitable nucleophiles to provide imidazopyridines and thiazoles.
- Shinde, Mahesh H.,Kshirsagar, Umesh A.
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p. 1455 - 1458
(2016/04/04)
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- Copper-Catalyzed Aerobic Oxidative Cyclization of Ketoxime Acetates with Pyridines for the Synthesis of Imidazo[1,2-a]pyridines
-
A copper(I)-catalyzed aerobic oxidative coupling of ketoxime acetates with simple pyridines for the synthesis of imidazo[1,2-a]pyridines has been developed. This reaction tolerates a wide range of functional groups and it affords a series of valuable imidazo[1,2-a]pyridines in high yields under mild conditions.
- Ren, Zhi-Hui,Zhao, Mi-Na,Yi, Yukun,Wang, Yao-Yu,Guan, Zheng-Hui
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p. 1920 - 1926
(2016/06/15)
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- A synthetic method of 2-phenyl-imidazo[1,2-a]pyridine compounds
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A synthetic method of 2-phenyl-imidazo[1,2-a]pyridine compounds is disclosed. Compared with the prior art, the method adopts a high-frequency mechanical grinding technique, is finished by a one-step reaction and is simple in operation, free of solvents in a reaction process and free of chemical agents with high toxicity. The method is short in reaction time and mild in reaction conditions, wherein the reaction can be finished in 90 min and can be performed at room temperature with a oscillation frequency of 30 Hz. The method is high in yield, and the highest yield can reach 94%. The method can rapidly and effectively synthesize the 2-phenyl-imidazo[1,2-a]pyridine compounds with strong electron withdrawing groups, while the 2-phenyl-imidazo[1,2-a]pyridine compounds with the strong electron withdrawing groups cannot be synthesized by traditional methods or are low in synthesis yield unless extremely extreme and strict reaction conditions are adopted.
- -
-
Paragraph 0048; 0049; 0050; 0051; 0052; 0055
(2016/10/10)
-
- Solvent- and catalyst-free synthesis of imidazo[1,2-a]pyridines under microwave irradiation
-
A facile solvent- and catalyst-free method for the synthesis of a series of imidazo[1,2-a]pyridines in good to excellent yields by the condensation of 2-aminopyridines with α-bromoketones under microwave irradiation has been developed. The important featu
- Kong, Dulin,Wang, Xianghui,Shi, Zaifeng,Wu, Mingshu,Lin, Qiang,Wang, Xin
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p. 529 - 531
(2016/10/05)
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- Synthesis of a dihydroquinoline based fluorescent cyanine for selective, naked eye, and turn off detection of Fe3+ ions
-
A cyanine dye was synthesized by condensing 6-formylated 1,2,2,4-tetramethyl-1,2-dihydroquinoline (TMDQ) and 1,7-dimethyl-2-phenylimidazo[1,2-a]pyridin-1-ium iodide. The probe was a selective sensor for ferric ions in aqueous ethanolic solution. The senso
- Vijay,Nandi,Samant, Shriniwas D.
-
p. 49724 - 49729
(2016/07/06)
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- Highly Efficient and Practical Thiocyanation of Imidazopyridines Using an N-Chlorosuccinimide/NaSCN Combination
-
A direct C–H thiocyanation of imidazo[1,2-a]pyridines, and a practical sequential one-pot condensation/C–H thiocyanation process, using a combination of N-chlorosuccinimide/NaSCN for the synthesis of 3-thiocyanatoimidazo[1,2-a]pyridines have been develope
- Zhang, Hailei,Wei, Qian,Wei, Shiqiang,Qu, Jingping,Wang, Baomin
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p. 3373 - 3379
(2016/07/23)
-
- A copper-catalyzed multi-component reaction accessing fused imidazo-heterocycles via C-H functionalization
-
An efficient synthesis of fused imidazo-heterocycles is described using Cu(OTf)2 in [bmim]BF4 by the multi-component reaction of pyridin-2(1H)-one or thiazol/benzo[d]thiazol-2(3H)-ones with O-tosylhydroxyl amine and acetophenones under microwave irradiation. The present method is very rapid and the product formation occurs via a C-H functionalization/tandem addition-cyclization process. The ionic liquid containing copper triflate is recovered and reused four times.
- Kumar, G. Santosh,Ragini, S. Pushpa,Kumar, A. Sanjeeva,Meshram
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p. 51576 - 51580
(2015/06/25)
-
- Direct one-pot synthesis of zolimidine pharmaceutical drug and imidazo[1,2-a]pyridine derivatives via I2/CuO-promoted tandem strategy
-
An efficient one-pot synthetic protocol was developed for the synthesis of imidazo[1,2-a]pyridines from easily available starting materials: Aromatic ketones, α,β-unsaturated ketones, β-keto esters and 2-aminopyridines. The present reaction proceeded well in MeOH under the media of I2/CuO. By using this method, the marketed drug zolimidine could be prepared easily with 95% yield. All these target products were characterized by NMR, HRMS and IR spectra. Furthermore, the target compound 3fa was determined by X-ray crystallographic analysis.
- Cai, Qun,Liu, Mei-Cai,Mao, Bi-Ming,Xie, Xuan,Jia, Feng-Cheng,Zhu, Yan-Ping,Wu, An-Xin
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p. 881 - 884
(2015/03/04)
-
- Regioselective Oxidative C-H Phosphonation of Imidazo[1,2-a]pyridines and Related Heteroarenes Mediated by Manganese(III) Acetate
-
Herein, we report a MnIII-mediated regioselective method for the direct C-H phosphonation of imidazo[1,2-a]pyridines by using dialkyl phosphites. 3-Phosphonated imidazo[1,2-a]pyridines are synthesized in good to excellent yields under the optimized reaction conditions. The present method is also applicable to the functionalization of related heteroarenes, and unlike previously reported methods, the present strategy works well with (NH)-heteroarenes. Regioselective synthesis of phosphonylated heteroarenes: A mild, direct, and regioselective C-H phosphonation of imidazo[1,2-a]pyridines and related heteroarenes has been developed. Unlike those previously reported, the present method also works with (NH)-heteroarenes.
- Yadav, Mahipal,Dara, Saidulu,Saikam, Varma,Kumar, Mukesh,Aithagani, Sravan Kumar,Paul, Satya,Vishwakarma, Ram A.,Singh, Parvinder Pal
-
supporting information
p. 6526 - 6533
(2015/10/19)
-
- Synthesis and photophysical properties of fluorescent arylstyrylimidazo[1,2-a]pyridine-based donor-acceptor chromophores
-
A series of novel fluorescent arylstyrylimidazo[1,2-a]pyridines was synthesized and fully characterized. All styryl derivatives have an E-configuration of the vinyl double bond as unequivocally shown by 1H NMR spectroscopy. It was observed that
- Sefero?lu, Zeynel,Ihmels, Heiko,?ahin, Ertan
-
p. 465 - 473
(2015/03/18)
-
- Iron(III)-catalyzed three-component domino strategy for the synthesis of imidazo[1,2-a]pyridines
-
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.
- Santra, Sougata,Mitra, Shubhanjan,Bagdi, Avik Kumar,Majee, Adinath,Hajra, Alakananda
-
supporting information
p. 5151 - 5155
(2014/12/10)
-
- Copper-catalyzed c-h functionalization of pyridines and isoquinolines with vinyl azides: Synthesis of imidazo heterocycles
-
Copper(I) iodide-catalyzed oxidative C(sp2)-H functionalization of pyridines and isoquinolines for the synthesis of imidazo[1,2-a]pyridines and 2-phenylimidazo[2,1-a]isoquinolines with vinyl azides under mild aerobic conditions is reported. Goo
- Donthiri, Ramachandra Reddy,Pappula, Venkatanarayana,Reddy, N. Naresh Kumar,Bairagi, Dipayan,Adimurthy, Subbarayappa
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p. 11277 - 11284
(2015/01/08)
-
- Heterogeneously copper-catalyzed oxidative synthesis of imidazo[1,2-a]pyridines using 2-aminopyridines and ketones under ligand- and additive-free conditions
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An efficient and mild heterogeneously CuCl2/nano-TiO 2-catalyzed aerobic synthesis of imidazo[1,2-a]pyridines from 2-aminopyridines and ketones has been developed using air as the oxidant in the absence of any ligands and additives. This strategy was compatible with a large range of substrates, including unactivated aryl ketones and unsaturated ketones and went through the C-H bond functionalization mechanism instead of I --assisted Ortoleva-King reaction to provide the corresponding imidazo[1,2-a]pyridines in good yields with low catalyst loading (0.8 mol%). Moreover, the heterogeneous catalyst can be successfully employed in gram-scale synthesis and reused many times without the significant loss of catalytic activity.
- Meng, Xu,Wang, Yanmin,Yu, Chaoying,Zhao, Peiqing
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p. 27301 - 27307
(2014/07/21)
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- Straightforward synthesis of various 2,3-diarylimidazo[1,2-a]pyridines in peg400 medium through one-pot condensation and C-H arylation
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PEG400 is described herein as a suitable medium for the condensation of various 2-amino pyridines with α-bromo ketones. 2-Arylimidazo[1,2-a]pyridines were synthetized in a short time through microwave irradiation in moderate to excellent yields
- Hiebel, Marie-Aude,Fall, Yacoub,Scherrmann, Marie-Christine,Berteina-Raboin, Sabine
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p. 4643 - 4650
(2014/08/05)
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- Conversion of pyridine to imidazo[1,2-a]pyridines by copper-catalyzed aerobic dehydrogenative cyclization with oxime esters
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A rapid and environmentally friendly conversion of pyridine to imidazo[1,2-a]pyridines has been developed via copper-catalyzed aerobic dehydrogenative cyclization with ketone oxime esters.
- Huang, Huawen,Ji, Xiaochen,Tang, Xiaodong,Zhang, Min,Li, Xianwei,Jiang, Huanfeng
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supporting information
p. 6254 - 6257
(2014/01/17)
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- Copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines: Synthesis of imidazopyridine derivatives
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A novel, efficient, and practical method for the synthesis of imidazopyridine derivatives has been developed through the copper-catalyzed aerobic oxidative C-H functionalization of substituted pyridines with N-(alkylidene)-4H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the N-N bond in the N-(alkylidene)-4H-1,2,4-triazol-4-amines and activation of an aryl C-H bond in the substituted pyridines. This is the first example of the preparation of imidazopyridine derivatives by using pyridines as the substrates by transition-metal-catalyzed C-H functionalization. This method should provide a novel and efficient strategy for the synthesis of other nitrogen heterocycles.
- Yu, Jipan,Jin, Yunhe,Zhang, Hao,Yang, Xiaobo,Fu, Hua
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supporting information
p. 16804 - 16808
(2014/01/06)
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- Copper(I) iodide-catalysed aerobic oxidative synthesis of imidazo [1,2-α]pyridines from 2-aminopyridines and methyl ketones
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We report here an operationally simple copper-catalysed synthesis of imidazo [1,2-α]pyridines through C-H activation with oxidative linkage of two C-N bonds under very mild conditions using molecular oxygen as a sole oxidant. The process allows the quick assembly of imidazo [1,2-α]pyridines including the antiulcer drug zolimidine from inexpensive and readily available 2-aminopyridines and methyl ketones with broad range of functional group tolerance.
- Mohan, Darapaneni Chandra,Donthiri, Ramachandra Reddy,Rao, Sadu Nageswara,Adimurthy, Subbarayappa
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supporting information
p. 2217 - 2221
(2013/10/01)
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- Copper-catalyzed synthesis of imidazo[1,2-a]pyridines through tandem imine formation-oxidative cyclization under ambient air: One-step synthesis of zolimidine on a gram-scale
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A new copper-catalyzed oxidative cyclization via C-H amination between 2-aminopyridines and methyl aryl/heteroaryl ketones has been developed under ambient air. Imidazo[1,2-a]pyridines containing a wide range of functional groups have been synthesized from basic and easily available starting materials. This simple, one-pot reaction protocol is applicable for the direct preparation of zolimidine (a marketed antiulcer drug) on a large scale. Copyright
- Bagdi, Avik Kumar,Rahman, Matiur,Santra, Sougata,Majee, Adinath,Hajra, Alakananda
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supporting information
p. 1741 - 1747
(2013/07/11)
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- Copper catalyzed tandem oxidative C-H amination/cyclizations: Direct access to imidazo[1,2-a]pyridines
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A simple and convenient strategy is described for the synthesis of imidazo[1,2-a]pyridines via inexpensive copper-catalyzed tandem imine formation and intramolecular aerobic oxidative C-H bond amination/cyclizations. An array of imidazo[1,2-a]pyridines were prepared by the reaction of readily available acetophenones and 2-aminopyridines in good to excellent yields (48-92%). The scope of the method was validated by a single step synthesis of Zolimidine, a drug used for peptic ulcers, in 61% yield. The Royal Society of Chemistry 2013.
- Pericherla, Kasiviswanadharaju,Kaswan, Pinku,Khedar, Poonam,Khungar, Bharti,Parang, Keykavous,Kumar, Anil
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p. 18923 - 18930
(2013/10/22)
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- Copper(I) iodide/boron trifluoride etherate-cocatalyzed aerobic dehydrogenative reactions applied in the synthesis of substituted heteroaromatic imidazo[1,2-a]pyridines
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Compared with the well-known palladium-catalyzed oxidative dehydrogenation coupling reactions, similar transforms initiated by copper/oxygen have attracted more and more attention. We have investigated a novel construction of heteroaromatic imidazo[1,2-a]
- Cai, Zhong-Jian,Wang, Shun-Yi,Ji, Shun-Jun
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supporting information
p. 2686 - 2692
(2013/10/21)
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- Iron(III)-Catalyzed Cascade Reaction between Nitroolefins and 2-Aminopyridines: Synthesis of Imidazo[1,2-a]pyridines and Easy Access towards Zolimidine
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The iron(III)-catalyzed one-pot cascade reaction between nitroolefins and 2-aminopyridines has been demonstrated for the synthesis of imidazo[1,2-a] pyridines by exploiting the bielectrophilic nature of nitroolefins. This methodology could be successfully
- Santra, Sougata,Bagdi, Avik Kumar,Majee, Adinath,Hajra, Alakananda
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supporting information
p. 1065 - 1070
(2013/06/05)
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- Heteroaromatic imidazo[1,2-a]pyridines synthesis from C-H/N-H oxidative cross-coupling/cyclization
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A novel silver-mediated highly selective C-H/N-H oxidative cross-coupling/cyclization between 2-aminopyridines and terminal alkynes has been demonstrated. This approach provided a simple way to construct heteroaromatic imidazo[1,2-a]pyridines. By using this protocol, the marketed drug zolimidine (antiulcer) could be synthesized easily.
- He, Chuan,Hao, Jing,Xu, Huan,Mo, Yiping,Liu, Huiying,Han, Juanjuan,Lei, Aiwen
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supporting information
p. 11073 - 11075,3
(2012/12/12)
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