- Synthesis and Optical Properties of Push–Push–Pull Chromophores Based on Imidazo[5,1,2-cd]indolizines and Naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines
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Four series of new push–push–pull chromophores based on two types of heterocyclic cores, namely imidazo[5,1,2-cd]indolizines and naphtho[1′,2′:4,5]imidazo[1,2-a]pyridines, and two types of linear π spacers, namely diphenylacetylene and biphenyl, were prep
- Maitra, Ratnava,Chen, Jie-Hong,Hu, Ching-Han,Lee, Hon Man
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- Synthesis of fused imidazoles based on γ-bromodypnone
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A new method based on the reaction of 4-bromo-1,3-diphenyl-2-buten-1-one with heterocyclic amines was proposed for the synthesis of fused imidazoles.
- Kovtunenko, Volodimir,Potikha, Lyudmila,Turov, Aleksandr
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- Hetarenes with a bridge nitrogen atom. 6. Ambident properties of the oxazolo[3,2-a]pyridinium nucleus in reactions with nucleophiles: Prediction and experiment
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We have studied the problem of ambident opening of five-membered and six-membered rings of the heteroaromatic oxazolo[3,2-a]pyridinium cation. A quantum chemical SINDO1 calculation of the energies of isomeric adducts of this cation with nucleophiles predi
- Babaev,Pasichnichenko,Maiboroda
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- One-Pot Tandem Amidation, Knoevenagel Condensation, and Palladium-Catalyzed Wacker Type Oxidation/C-O Coupling: Synthesis of Chromeno-Annulated Imidazopyridines
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A direct one-pot synthesis of chromeno-annulated imidazo[1,2-a]pyridines is achieved by the reaction of 2-amino-1-(2-ethoxy-2-oxoethyl)pyridinium salts with 2-bromoarylaldehydes using Pd(TFA)2 as a catalyst and Cu(OAc)2 as an oxidant
- Pandey, Khima,Rangan, Krishnan,Kumar, Anil
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- Diversity-oriented synthesis toward aryl- And phosphoryl-functionalized imidazo[1,2-a]pyridines
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We report herein an efficient synthesis of diversely polysubstituted imidazo[1,2-a]pyridines, a family of aza-heterocycles endowed with numerous biological properties, through a sequence involving two consecutive palladium-catalyzed cross-coupling reactions. First, we demonstrated that a Hirao coupling occurred straightforwardly in high yields at positions 3, 5, and 6 of imidazopyridine derivatives, giving access to a wide variety of substituted phosphonates, phosphinates, and phosphine oxides. In a second step, direct CH-arylation of phosphorylimidazopyridines with aryl halides was found to be effective and fully selective, leading to 3-aryl-substituted imidazopyridines in moderate to high yields depending on steric hindrance.
- Gernet, Aurelie,Sevrain, Nicolas,Volle, Jean-Noel,Ayad, Tahar,Pirat, Jean-Luc,Virieux, David
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- Synthesis of C3-Cyanomethylated Imidazo[1,2- a ]pyridines via Ultrasound-Promoted Three-Component Reaction under Catalyst- and Oxidant-Free Conditions
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An efficient synthesis of C3-cyanomethylated imidazo[1,2-α]pyridines via ultrasound-promoted three-component reaction under catalyst-free, oxidant-free, and mild conditions has been developed. A series of C3-cyanomethylated imidazo[1,2-α]pyridines were rapidly prepared with satisfactory yields and good functional group compatibility. This strategy cloud also be applied to the synthesis of zolpidem and alpidem in short steps.
- Wu, Qingguo,Yang, Haifeng,Zhang, Jian,Zhang, Jie,Zhang, Yufeng
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supporting information
p. 264 - 268
(2022/02/05)
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- Solvent and catalyst-free synthesis of imidazo[1,2-a]pyridines by grindstone chemistry
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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
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p. 250 - 259
(2020/10/23)
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- One-Pot Synthesis of C3-Alkylated Imidazopyridines from α-Bromocarbonyls under Photoredox Conditions
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A convenient strategy is presented for the synthesis of C3-alkylated imidazopyridines through one pot condensation and alkylation of α-bromocarbonyl compounds with 2-aminopyridines. A series of C3-alkylated imidazopyridines were obtained in moderate to hi
- Li, Jingyu,Liu, Ping,Sun, Peipei,Tong, Jinwen,Zhan, Yanling
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supporting information
p. 4541 - 4545
(2021/08/27)
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- Palladium(ii) catalyzed site-selective C-H olefination of imidazo[1,2-: A] pyridines
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Herein, we disclose an efficient Pd(ii)-catalyzed site selective C8 alkenylation of imidazo[1,2-a]pyridines with electronically biased olefinic substrates. Notably, besides the presence of four C-H sites available, selective mono-alkenylation was achieved
- Tali, Javeed Ahmad,Kumar, Gulshan,Singh, Davinder,Shankar, Ravi
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supporting information
p. 9401 - 9406
(2021/11/17)
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- Metal-free oxidative decarbonylative halogenation of fused imidazoles
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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
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supporting information
p. 20551 - 20555
(2021/11/23)
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- Electrochemical Oxidative C3 Acyloxylation of Imidazo[1,2- a]pyridines with Hydrogen Evolution
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The C3-functionalized imidazo[1,2-a]pyridines are versatile nitrogen-fused heterocycles; however, the methods for the C3 acyloxylation of imidazo[1,2-a]pyridines have never been reported. Herein we demonstrate the electrochemical oxidative C3 acyloxylation of imidazo[1,2-a]pyridines for the first time. Notably, by using electricity, the electrochemical oxidative C3 acyloxylation of imidazo[1,2-a]pyridines was carried out under mild conditions. Moreover, in addition to aromatic carboxylic acids, alkyl carboxylic acids were also competent substrates.
- Yuan, Yong,Zhou, Zhilin,Zhang, Lin,Li, Liang-Sen,Lei, Aiwen
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supporting information
p. 5932 - 5936
(2021/08/16)
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- Micellar Catalysis: Visible-Light Mediated Imidazo[1,2-a]pyridine C—H Amination with N-Aminopyridinium Salt Accelerated by Surfactant in Water
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A light-promoted metal-free protocol for the amination of imidazo[1,2-a]pyridines with N-aminopyridinium salt by the assistance of surfactants in water was reported, charactering mild and environmentally benign conditions, as well as great functional grou
- Yang, Zhonglie,Cao, Kun,Peng, Xiaoyan,Lin, Li,Fan, Danchen,Li, Jun-Long,Wang, Jingxia,Zhang, Xiaobin,Jiang, Hezhong,Li, Jiahong
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supporting information
p. 3347 - 3352
(2021/10/20)
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- Structural Determinants for the Mode of Action of Imidazopyridine DS2 at δ-Containing γ-Aminobutyric Acid Type A Receptors
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Despite the therapeutic relevance of δ-containing γ-aminobutyric acid type A receptors (GABAARs) and the need for δ-selective compounds, the structural determinants for the mode and molecular site of action of δ-selective positive allosteric modulator imi
- Rostrup, Frederik,Falk-Petersen, Christina B.,Harpsoe, Kasper,Buchleithner, Stine,Conforti, Irene,Jung, Sascha,Gloriam, David E.,Schirmeister, Tanja,Wellendorph, Petrine,Frolund, Bente
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p. 4730 - 4743
(2021/05/06)
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- Regioselective C-H dithiocarbamation of indolizines with tetraalkylthiuram disulfide under metal-free conditions
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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
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supporting information
p. 5284 - 5288
(2021/06/28)
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- Metal-free, Tf2NH-catalyzed 1, 6-conjugate addition of imidazopyridine to para-quinone methides: Easy access to C3-functionalized triarylmethane imidazopyridine
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An inexpensive and commercially available Tf2NH-catalyzed 1,6-conjugate addition of imidazopyridine (IMPY) heterocycles to para-quinone methides (p-QMs) is reported. The present transformation provides a diverse class of C3-functionalized triarylmethanes heterocyclic derivatives of imidazopyridine. These metal-free transformations provided a very broad substrate scope of conjugate addition product with a high yield up to 97% within a short duration.
- Khonde, Nilesh S.,Said, Madhukar S.,Sabane, Jagjivan K.,Gajbhiye, Jayant M.,Kumar, Pradeep
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supporting information
(2021/10/30)
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- Molecular iodine enabled generation of iminyl radicals from oximes: A facile route to imidazo[1,2-a]pyridines and its regioselective C-3 sulfenylated products from simple pyridines
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An iodine promoted simple and environment friendly protocol has been developed to access imidazo[1,2-a]pyridines from unfunctionalized pyridines and oxime esters. This straightforward method efficiently converts the substrates into corresponding products affording moderate to good yields with large functional group tolerance. Additionally extensive investigation revealed that regioselective domino C-3 methyl sulfenylated imidazo[1,2-a]pyridines were also accessible first time from pyridines and oxime esters in DMSO solvent. The reaction operates through metal-free generation of iminyl radicals from easily accessible oxime esters, to build up the second heterocyclic ring on pyridines.
- Singh, Deepak,Chowdhury, Soumyadeep Roy,Pramanik, Shyamal,Maity, Soumitra
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supporting information
(2021/04/22)
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- Palladium-Catalyzed C-N Coupling of Pyrazole Amides with Triazolo- And Imidazopyridine Bromides in Ethanol
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An efficient palladium-catalyzed coupling between a pyrazole amide and a heteroaryl bromide was developed to enable the streamlined synthesis of a lead candidate for schizophrenia treatment. Process robustness and scalability were achieved using ethanol a
- Bliss, Fritz,Fantasia, Serena,Le Coz, Erwann,Püntener, Kurt
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p. 457 - 468
(2021/02/01)
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- Synthetic method of imidazopyridine compounds
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The invention provides a novel method for synthesizing imidazopyridine compounds. According to the invention, aminopyridine compounds and sulfur ylide are used as original reaction substrates, iron phthalocyanine (FeIIPc) is used as a catalyst, and a series of the imidazopyridine compounds are obtained under the condition that the advantages of mildness, greenness, high efficiency, wide substrateuniversality and the like are achieved.
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Paragraph 0056; 0065-0067
(2021/03/24)
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- Design, synthesis and anticancer activity of sulfenylated imidazo-fused heterocycles
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We report herein, the design, synthesis and study of anticancer properties of sulfenylated 2-phenylimidazo[1,2-a]pyridines and their analogues. A set of twenty sulfenylated imidazo[1, 2-a]pyridine derivatives were synthesized. Whereby elusive amendments to the imidazo[1,2-a]pyridine motif confer dramatic changes in functional affinity of a novel action to modulate anticancer activity in seven different human cancer cell lines i.e.: MDA MB 231 (breast), HepG2 (liver), Hela (cervical), A549 (lung), U87MG (glioblastoma), SKMEL-28 (skin melanoma) and DU-145 (prostate) by employing MTT assay. Among the series, compounds 4e (naphthalene), 4f (styrene) and 4h (thiomethyl) showed potent activity towards human liver cancer cells HepG2. Cell cycle analysis results revealed that these compounds arrested the cell cycle at G2/M phase and induced apoptosis in human liver cancer cells HepG2. It was further confirmed by Hoechst staining, Measurement of mitochondrial membrane potential (ΔΨm) and Annexin V-FITC assay.
- Chitrakar, Ravi,Rawat, Deepa,Sistla, Ramakrishna,Subbarayappa, Adimurthy,Vadithe, Lakshma Nayak
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supporting information
(2021/08/13)
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- 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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- Iodine-Mediated Sulfenylation of Imidazo[1,2- a ]pyridines with Ethyl Arylsulfinates
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A simple iodine-mediated approach is reported for the synthesis of sulfenylated imidazo[1,2- a ]pyridines through the reaction of imidazo[1,2- a ]pyridines with ethyl arylsulfinates under mild conditions. The reaction scope was investigated, and a plausible mechanism is proposed to elucidate the reaction process and activation mode. The results indicate that ethyl sulfinates are efficient sulfur sources for the construction of C-S bonds.
- Sun, Jian,Mu, Yangxiu,Iqbal, Zafar,Hou, Jing,Yang, Minghua,Yang, Zhixiang,Tang, Dong
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supporting information
p. 1014 - 1018
(2021/03/15)
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- Imidazopyridine compound, pharmaceutical composition containing the same, and preparation method and application thereof (by machine translation)
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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)
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Paragraph 0062-0066
(2020/05/01)
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- Microwave-assisted synthesis and luminescent activity of imidazo[1,2-a]pyridine derivatives
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In this work, a series of phenacyl bromide derivatives was synthesized and employed as key intermediate for the synthesis of substituted imidazo[1,2-a]pyridines. First, phenacyl bromide molecules were obtained from the bromination reaction of acetophenones assisted by microwave irradiation, obtaining the products 4a-v in a 15 minutes reaction with yields in the range of 50% to 99%. Subsequently, the conjugation of these molecules with 2-aminopyridine conduced to the production of imidazo[1,2-a]pyridine derivatives (7a-v) in a 60-second reaction with yields of 24% to 99%. Improved yields were determined with respect to those obtained with more tedious methodologies like thermally and mechanically assisted routes. Intense luminescence emissions in the purple and blue regions of the electromagnetic spectra were observed under UV excitation according to the nature of the substituents. This environmentally friendly methodology is expected to constitute an important class of organic compounds for the development of biomarkers, photochemical sensors, and medicinal applications.
- Rodríguez, Juan C.,Maldonado, Rony A.,Ramírez-García, Gonzalo,Díaz Cervantes, Erik,de la Cruz, Fabiola N.
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supporting information
p. 2279 - 2287
(2020/03/16)
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- Direct Oxygenation of C-H Bonds through Photoredox and Palladium Catalysis
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This report presents the oxygenation of C-H bonds via the merger of photocatalysis and Pd catalysis. Herein, we describe the utilization of a photocatalyst to oxidize an organopalladium(II) intermediate to high-valent PdIII or PdIV intermediates, which promotes the formation of C-O bonds. The demonstrated method works efficiently with various directing groups, such as oxime ether and benzothiazole. The applicability of this direct C-O bond formation method is shown by synthesizing several metal complexes of 2-(benzo[d]thiazol-2-yl)phenol that can be used in organic light-emitting diodes and pharmaceuticals.
- Paul, Amrita,Shah, Sk. Sheriff,Shee, Maniklal,Singh, Amit Kumar,Singh, N. D. Pradeep
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p. 3426 - 3439
(2020/03/23)
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- PhI(OAc)2-mediated oxidative C[sbnd]H sulfoximination of imidazopyridines under mild conditions
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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
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supporting information
(2019/11/26)
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- Design, one-pot green synthesis and antimicrobial evaluation of novel imidazopyridine bearing pyran bis-heterocycles
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Herein, we report design, one pot synthesis and antibacterial evaluation of novel imidazopyridine bearing pyran bis-heterocycles. The compounds were synthesized in an aqueous solution of gluconic acid under both conventional heating and ultrasound irradiation. The target compounds were obtained in good to moderate yields with yield of 65–88% in 20–60 min under ultrasonic irradiation. The compounds were characterized by spectroscopic methods IR, 1H NMR, 13C NMR, MS and HRMS. X-ray single crystal structure of 7i was also determined. The compounds were evaluated for antibacterial activity by measuring zone of inhibition using disk diffusion method that revealed that some compounds were inhibiting the growth of Gram +ve and Gram -ve bacteria. Result of minimum inhibitory concentration (MIC) showed that 7a, 7h & 7k from a series 7a-7k inhibited the growth of S. aureus. The minimum bactericidal concentration (MBC) value was determined for 7a, 7h & 7k. MBC/MIC ratio of the derivatives 7a, 7k & 7h suggest former two derivatives act as bactericidal agent & later act as bacteriostatic agents against Gram +ve bacteria. Haemolysis results showed that compounds are non-cytotoxic to erythrocytes.
- Thakur, Ashima,Pereira, Gavin,Patel, Chetananda,Chauhan, Vinita,Dhaked, Ram Kumar,Sharma, Abha
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- Unconventional Reactivity with DABCO-Bis(sulfur dioxide): C–H Bond Sulfenylation of Imidazopyridines
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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
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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
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supporting information
p. 363 - 368
(2020/02/27)
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- Ultrasound-Promoted and Base-Mediated Regioselective Bromination of Imidazo[1,2- a ]pyridines with Pyridinium Tribromide
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By using pyridinium tribromide as the bromo source, an efficient- and practical protocol for the synthesis of C3-brominated imidazo-[1,2- a ]pyridines through ultrasound-promoted and Na 2CO 3-mediated regioselective bromination of im
- Jiang, Hongmei,Guo, Dingyi,Zhang, Yixin,Shen, Qin-Peng,Tang, Shiyun,You, Junheng,Huo, Yi,Wang, Huixian,Gui, Qing-Wen
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p. 2713 - 2720
(2020/09/15)
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- Temperature-Controlled Chalcogenation and Chalcogenocyanation of Imidazopyridines in Water under Transition Metal-Free Conditions
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A sustainable and transition metal-free approach for C3 chalcogenation and chalcogenocyanation of imidazopyridines with KXCN (X = S or Se) has been developed under mild conditions. Importantly, this reaction was performed in the presence of catalytic iodi
- Zhu, Yu-Shen,Xue, Yuting,Liu, Wannian,Zhu, Xinju,Hao, Xin-Qi,Song, Mao-Ping
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p. 9106 - 9116
(2020/08/14)
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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
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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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- SMAD3 INHIBITORS
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Smad3 inhibitor compounds, specifically a compound of Formula 1 or Formula 2, or a pharmaceutically acceptable salt thereof, and its use in treating or preventing cell proliferation or cancer in a subject are provided.
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- SELECTIVE LIGANDS OF HUMAN CONSTITUTIVE ANDROSTANE RECEPTOR
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The present invention provides a structurally novel class of heterocyclic compounds of general formula I wherein L1 is heteroaryl and L2 is heteroaryl or aryl. The novel compounds are useful in a method of prevention or treatment of a condition which is m
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(2020/11/12)
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- Annulation of imidazo[1,2-: A] pyridines under metal-free conditions
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A base promoted protocol for the synthesis of benzo[a]imidazo[5,1,2-cd]indolizines from 2-arylimidazo[1,2-a]pyridines and benzyne precursors under metal-free conditions has been developed. Without a transition metal, double C(sp2)-H activation of 2-phenylimidazo[1,2-a]pyridines under basic conditions was achieved. This method is also applicable for the annulation of imidazo[1,2-a]pyrimidine and naphthylamine under the same conditions. These annulated molecules showed fluorescence characteristics and hence their photo physical properties were evaluated. This journal is
- Semwal, Rashmi,Joshi, Abhisek,Kumar, Rahul,Adimurthy, Subbarayappa
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supporting information
p. 20530 - 20534
(2020/12/28)
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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
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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
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supporting information
p. 8002 - 8006
(2020/11/02)
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- A simple and efficient route to 2-arylimidazo[1,2-a]pyridines and zolimidine using automated grindstone chemistry
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A green and efficient mechanochemical method for the synthesis of a series of 2-arylimidazo[1,2-a]pyridines was developed using an electrical grinder. I2 catalyzed mechanochemical grinding facilitates the cyclocondensation reaction between various aryl methyl ketones and 2-aminopyridines to afford 2-arylimidazo[1,2-a]pyridines in good yields at ambient temperature. The method was successfully used for the gram-scale synthesis of a marketed drug, zolimidine. The noticeable advantages of this environmentally sustainable protocol include mild conditions, simple instrumentation, inexpensive catalyst, atom economy, short reaction time etc.
- Das, Dharmendra,Bhutia, Zigmee T.,Panjikar, Padmini C.,Chatterjee, Amrita,Banerjee, Mainak
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supporting information
p. 4099 - 4107
(2020/09/09)
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- One-pot NBS-promoted synthesis of imidazoles and thiazoles from ethylarenes in water
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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
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- Ultrasound-assisted synthesis of imidazo[1,2-a]pyridines an d sequential one-pot preparation of 3-selanyl-imidazo[1,2-a]pyridine derivatives
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A simple and rapid method to synthesize imidazo[1,2-a]pyridines starting from 2-aminopyridine and 2-bromoacetophenone derivatives under ultrasonic irradiation was developed. This protocol tolerates a wide range of 2-bromoacetophenone derivatives to produce a variety of imidazo[1,2-a]pyridines in good to excellent yields. Additionally, the one-pot preparation of 3-(organylselanyl)imidazo[1,2-a]pyridines via a sequential method is presented. In this case, different diorganyl diselenides were used as starting materials to afford the corresponding coupling products in excellent yields and short reaction times under sonication. The reactions were conducted in PEG-400, a cheap and nontoxic solvent, compatible with the ultrasound conditions in an environmentally benign process.
- Vieira, Beatriz M.,Padilha, Nathalia,Nascimento, Nelson M.,Perin, Gelson,Alves, Diego,Schumacher, Ricardo F.,Lenard?o, Eder J.
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- Metal-Free Site-Specific Hydroxyalkylation of Imidazo[1,2- A[pyridines with Alcohols through Radical Reaction
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An effective approach to realize the direct hydroxyalkylation of imidazo[1,2-a]pyridines with alcohols promoted by di-tert-butyl peroxide was described without any metal catalyst. It is the first time that the dehydrogenative C(sp3)-C(sp2) coupling of imidazo[1,2-a]pyridines with alcohols occurred regioselectively at the C-5 position of imidazo[1,2-a]pyridines. Multisubstituted imidazopyridine derivatives were smoothly synthesized in moderate to good yields. Through a series of control experiments, a free-radical pathway was proposed to explain the experiment.
- Jin, Shengzhou,Xie, Bo,Lin, Sen,Min, Cong,Deng, Ruihong,Yan, Zhaohua
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supporting information
(2019/05/07)
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- Metal-Free Site-Specific Hydroxyalkylation of Imidazo[1,2- a]pyridines with Alcohols through Radical Reaction
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An effective approach to realize the direct hydroxyalkylation of imidazo[1,2-a]pyridines with alcohols promoted by di-tert-butyl peroxide was described without any metal catalyst. It is the first time that the dehydrogenative C(sp3)-C(sp2) coupling of imidazo[1,2-a]pyridines with alcohols occurred regioselectively at the C-5 position of imidazo[1,2-a]pyridines. Multisubstituted imidazopyridine derivatives were smoothly synthesized in moderate to good yields. Through a series of control experiments, a free-radical pathway was proposed to explain the experiment.
- Jin, Shengzhou,Xie, Bo,Lin, Sen,Min, Cong,Deng, Ruihong,Yan, Zhaohua
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supporting information
p. 3436 - 3440
(2019/05/10)
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- Eucalyptol: A new solvent for the synthesis of heterocycles containing oxygen, sulfur and nitrogen
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We report here the first investigation of the use of eucalyptol as a new solvent for organic transformations. Heterocycles containing oxygen, sulfur and nitrogen were chosen as targets or as starting materials for widely used palladium-catalysed cross-cou
- Campos, Joana F.,Scherrmann, Marie-Christine,Berteina-Raboin, Sabine
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supporting information
p. 1531 - 1539
(2019/03/26)
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- BENZO-IMIDAZOINDOLIZINE DERIVATIVE, ORGANIC ELECTROLUMINESCENCE ELEMENT MATERIAL USING THE SAME, AND ORGANIC ELECTROLUMINESCENCE ELEMENT AND ELECTRONIC DEVICE USING THE SAME
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The present invention relates to benzo-imidazoindolizine derivatives, organic electroluminescence devices comprising said derivative, and the use of said derivative in organic electroluminescence devices.
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Page/Page column 136-137
(2019/08/29)
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- Palladium(II)/Copper(II)-Catalyzed C–H Sulfidation or Selenation of Arenes Leading to Unsymmetrical Sulfides and Selenides
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A novel palladium(II)/copper(II)-catalyzed sulfidation of the C–H bond in electron-rich arenes and in pentafluorobenzene with disulfides was developed. This catalytic system can be used to efficiently produce various types of either unsymmetrical aryl sulfides or alkyl aryl sulfides. The present protocol could also be applied to the direct preparation of unsymmetrical aryl selenides via C–H selenation.
- Nishino, Kota,Tsukahara, Shouya,Ogiwara, Yohei,Sakai, Norio
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supporting information
p. 1588 - 1593
(2019/02/09)
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- Rhodium(II)-Catalyzed Regioselective C3-Alkylation of 2-Arylimidazo[1,2-a]pyridines with Aryl Diazoesters
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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
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supporting information
p. 2094 - 2106
(2019/03/21)
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- Electrochemical Oxidative C—H Sulfenylation of Imidazopyridines with Hydrogen Evolution
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Selective oxidative C—H sulfenylation of imidazopyridine heterocycles is achieved using an undivided electrolytic cell. The reaction avoids the use of stoichiometric amount of external chemical oxidant and produces hydrogen gas as the only byproduct. Both
- Yuan, Yong,Cao, Yangmin,Qiao, Jin,Lin, Yueping,Jiang, Xiaomei,Weng, Yaqing,Tang, Shan,Lei, Aiwen
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supporting information
p. 49 - 52
(2019/01/04)
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- Use of imidazo[1,2-a]pyridine as a carbonyl surrogate in a mannich-like, catalyst free, one-pot reaction
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Derivatization of imidazo[1,2-a]pyridine scaffolds have gained considerable attention due to the biological significance of therapeutics based on the imidazopyridine core. By utilizing a catalyst-free, “Mannich type” reaction, we developed a simple and efficient protocol to aminomethylate the C-3 position of imidazo[1,2-a]pyridine through a multicomponent, de-carboxylation reaction involving imidazo[1,2-a]pyridine, a secondary amine, and glyoxylic acid. The developed protocol re-quires mild reaction conditions and furnishes diverse imid-azo[1,2-a]pyridine analogues from commercially available starting materials. Additionally, the current protocol improves prior methods, which were limited by the amine substrate scope. Taken together, this current methodology permits rapid diversification of imidazo[1,2-a]pyridines to enhance combinatorial efficiency in the drug discovery processes.
- Naresh, Gunaganti,Lakkaniga, Naga Rajiv,Kharbanda, Anupreet,Yan, Wei,Frett, Brendan,Li, Hong-Yu
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p. 770 - 777
(2019/01/14)
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- Transition-Metal-Free Direct Trifluoromethylation and Perfluoroalkylation of Imidazopyridines under Mild Conditions
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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
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supporting information
p. 1559 - 1563
(2019/02/19)
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- Iodine-Mediated Multicomponent Synthesis of 3-Sulfenylimidazo[1,2- a ]pyridines from 2-Aminopyridines, Ketones, and Sulfonyl Hydrazides
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A one-pot multicomponent reaction for the synthesis of 3-sulfenylimidazo[1,2- a ]pyridines from readily available 2-aminopyridines, ketones, and sulfonyl hydrazides, mediated by molecular iodine, has been developed. The transformations proceed smoothly wi
- Hu, Sipei,Du, Shiying,Yao, Yunjie,Yang, Zuguang,Ren, Hongjun,Chen, Zhengkai
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supporting information
p. 625 - 629
(2019/03/07)
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- Electrochemical oxidative C-H/N-H cross-coupling for C-N bond formation with hydrogen evolution
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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
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supporting information
p. 1809 - 1812
(2019/02/12)
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- Rapid Construction of Fused Heteropolycyclic Aromatics via Palladium-Catalyzed Domino Arylations of Imidazopyridine Derivatives
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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
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supporting information
p. 4402 - 4406
(2019/05/08)
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- Gluconic acid promoted cascade reactions of 2-phenylimidazo[1,2-a] pyridine-3-carbaldehyde with cyclohexane-1,3-dione to create novel fused bisheterocycles
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Here in, we described the synthesis of novel bisheterocycles imidazopyridine bearing xanthenedione by reacting various substituted 2-phenylimidazo [1,2-a] pyridine-3-carbaldehyde with cyclohexane-1,3-dione in gluconic acid aqueous solution (GAAS) via a ta
- Patel, Chetananda,Thakur, Ashima,Pereira, Gavin,Sharma, Abha
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supporting information
p. 1836 - 1846
(2019/05/15)
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- Iodide-Catalyzed Phosphorothiolation of Heteroarenes Using P(O)H Compounds and Elemental Sulfur
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Organothiophosphates have found widespread application as biologically active compounds and synthetic intermediates in medicinal chemistry. The first transition-metal-free one-pot direct synthesis of heterocyclic phosphorothioates involving indole or imidazo[1,2-a]pyridine derivatives, elemental sulfur, and P(O)H compounds is presented. The use of NaI or KI as a catalyst, tert-butyl hydroperoxide as an oxidant, various indole and imidazo[1,2-a]pyridine derivatives are tolerant in this transformation, affording the corresponding products in good to excellent yields. Moreover, this method can be easily adapted to large-scale preparation. O,O-Diethyl S-(1-phenyl-1H-indol-3-yl) phosphorothioate presents potent anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 cells in a dose-dependent manner. (Figure presented.).
- Shi, Shanshan,Chen, Jun,Zhuo, Shaohua,Wu, Zi'ang,Fang, Meijuan,Tang, Guo,Zhao, Yufen
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supporting information
p. 3210 - 3216
(2019/05/16)
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- Formation of Methylene Linkage for N-Heterocycles: Sequential C-H and C-O Bond Functionalization of Methanol with Cosolvent Water
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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
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p. 6928 - 6939
(2019/06/14)
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- Chemodivergent synthesis of: N -(pyridin-2-yl)amides and 3-bromoimidazo[1,2- a] pyridines from α-bromoketones and 2-aminopyridines
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N-(Pyridin-2-yl)amides and 3-bromoimidazo[1,2-a]pyridines were synthesized respectively from α-bromoketones and 2-aminopyridine under different reaction conditions. N-(Pyridin-2-yl)amides were formed in toluene via C-C bond cleavage promoted by I2/s
- Liu, Yanpeng,Lu, Lixue,Zhou, Haipin,Xu, Feijie,Ma, Cong,Huang, Zhangjian,Xu, Jinyi,Xu, Shengtao
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p. 34671 - 34676
(2019/11/13)
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