65964-63-8Relevant academic research and scientific papers
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
Singh, Deepak,Chowdhury, Soumyadeep Roy,Pramanik, Shyamal,Maity, Soumitra
, (2021/04/22)
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.
Solvent and catalyst-free synthesis of imidazo[1,2-a]pyridines by grindstone chemistry
Godugu, Kumar,Nallagondu, Chinna Gangi Reddy
, p. 250 - 259 (2020/10/23)
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
CuCl2-catalyzed N[sbnd]O bond cleavage of oxime esters: Approach to imidazoheterocycles and furo[3,2-c]chromenyl fused imidazoles
Gudimella, Santosh K.,Kaur, Amanpreet,Kumar, Ram,Samanta, Sampak
supporting information, (2020/07/08)
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.
Use of imidazo[1,2-a]pyridine as a carbonyl surrogate in a mannich-like, catalyst free, one-pot reaction
Naresh, Gunaganti,Lakkaniga, Naga Rajiv,Kharbanda, Anupreet,Yan, Wei,Frett, Brendan,Li, Hong-Yu
, p. 770 - 777 (2019/01/14)
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.
Formation of Methylene Linkage for N-Heterocycles: Sequential C-H and C-O Bond Functionalization of Methanol with Cosolvent Water
Li, Na,Bai, Jinku,Zheng, Xiaolin,Rao, Honghua
, p. 6928 - 6939 (2019/06/14)
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.
Novel one step synthesis of imidazo[1,2-a]pyridines and Zolimidine via iron/iodine-catalyzed Ortoleva-King type protocol
Ujwaldev, Sankuviruthiyil Mohanan,Rohit,Harry, Nissy Ann,Anilkumar, Gopinathan
, (2019/07/30)
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.
Efficient Access to Imidazo[1,2- a] pyridines/pyrazines/pyrimidines via Catalyst-Free Annulation Reaction under Microwave Irradiation in Green Solvent
Rao, R. Nishanth,Mm, Balamurali,Maiti, Barnali,Thakuria, Ranjit,Chanda, Kaushik
supporting information, p. 164 - 171 (2018/03/21)
An expeditious catalyst-free heteroannulation reaction for imidazo[1,2-a]pyridines/pyrimidines/pyrazines was developed in green solvent under microwave irradiation. Using H2O-IPA as the reaction medium, various substituted 2-aminopyridines/pyra
Catalyst free, C-3 functionalization of imidazo[1,2-a]pyridines to rapidly access new chemical space for drug discovery efforts
Gunaganti, Naresh,Kharbanda, Anupreet,Lakkaniga, Naga Rajiv,Zhang, Lingtian,Cooper, Rose,Li, Hong-yu,Frett, Brendan
supporting information, p. 12954 - 12957 (2018/11/23)
Multicomponent reactions (MCRs) are robust tools for the rapid synthesis of complex, small molecule libraries for use in drug discovery and development. By utilizing MCR chemistry, we developed a protocol to functionalize the C-3 position of imidazo[1,2-a
Facile synthesis of imidazo[1,2-a]pyridines promoted by room-temperature ionic liquids under ultrasound irradiation
Paengphua, Piyawat,Chancharunee, Sirirat
, p. 1835 - 1840 (2018/09/10)
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.].
A synthetic method of 2-phenyl-imidazo[1,2-a]pyridine compounds
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Paragraph 0048; 0049; 0050; 0051; 0052; 0055, (2016/10/10)
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.
