Imidazopyridine is one of the important fused bicyclic 5-6 heterocycles and it is recognized as a "drug prejudice" scaffold due to its wide range of applications in medicinal chemistry. This moiety is also useful in material science because of its structural character. Synthesis of this moiety from the easily available chemicals is desirable due to its tremendous use in the various branches of chemistry. Here we report a review on the synthesis of this scaffold employing different strategies such as condensation, multicomponent reactions, oxidative coupling, tandem reactions, aminooxygenation, and hydroamination reactions.
Catalytic oxidative trifluoromethylation of imidazopyridines has been carried out at room temperature through the functionalization of the sp(2) C-H bond employing Langlois reagent under ambient air. A library of 3-(trifluoromethyl)imidazo[1,2-a]pyridines with broad functionalities have been synthesized regioselectively. This methodology is also applicable to imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.
A simple and efficient protocol has been developed for the synthesis of 3‐aroylimidazopyridines via copper(II) acetate‐catalyzed aerobic oxidative amination. A library of 3‐aroylimidazopyridines was synthesized from readily accessible chalcones and 2‐aminopyridines with high yields and regioselectivity. The reaction proceeds through a tandem Michael addition followed by an intramolecular oxidative amination. The successful application of this methodology for a gram‐scale reaction indicates its potential for bulk synthesis.magnified image
The present review highlights different types of nanoferrites and their surface-modified composites as alternative adsorbents in waste water treatment.
A simple and practical method has been developed for the regioselective nitrosylation of imidazopyridines via C(sp(2))-H bond functionalization using tert-butyl nitrite under mild reaction conditions in a short time. A library of 3-nitrosoimidazopyridines with broad functionalities was synthesized in near quantitative yields. The present protocol is also applicable to imidazo[2,1-b]thiazole and benzo[d]imidazo[2,1-b]thiazole.
A unique iron-catalyzed oxidative diamination of nitroalkene with 2-aminopyridine for the synthesis of 2-nitro-3-arylimidazo[1,2-a]pyridines with complete regioselectivity has been achieved under mild and aerobic reaction conditions. This is the first method for the synthesis of 2-nitroimidazo[1,2-a]pyridines. These scaffolds were also synthesized directly from styrenes.
An efficient and environmentally benign method has been developed for the synthesis of symmetrical and unsymmetrical aromatic azo compounds through phenyliodine(III) diacetate (PIDA) mediated oxidative dehydrogenative coupling of anilines in high yields. The scope of the reaction is broad for both homo‐ and cross‐dimerization. A plausible reaction mechanism has been proposed based on a structurally characterized key intermediate, suggesting that ethanol is involved in the reaction pathway. Fast reaction, metal‐free conditions, and functional‐group tolerance are advantages of this method.
The FeCl3/ZnI2-catalyzed aerobic oxidative cyclization between 2-aminobenzothiazole and ketone/chalcone for the synthesis of benzo[d]imidazo[2,1-b]thiazole is described. A variety of fused benzoimidazothiazole derivatives are obtained by this protocol.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.