Reaction of β-Lactam Carbenes with 2-Pyridyl Isonitriles: A One-Pot Synthesis of 2-Carbonyl-3-(pyridylamino)imidazo[1,2-a]pyridines Useful as Fluorescent Probes for Mercury Ion

Abstract

The one-pot reaction of β-lactam carbenes with 2-pyridyl isonitriles followed by an acidic hydrolysis was reported, which produced 2-carbonyl-3-(pyridylamino)imidazo[1,2-a]pyridines in moderate to good yields. Among the resulting novel imidazo[1,2-a]pyridine derivatives, 1-(6-chloro-3-(5-chloropyridin-2-ylamino)imidazo[1,2-a]pyridin-2-yl)-2-ethylbutan-1-one was demonstrated to be an efficient fluorescent probe for mercury ion both in acetonitrile and in buffered aqueous solution.

Synthesis of Triphenylamine-Imidazo[1,2-a]pyridine via Groebke–Blackburn–Bienaymé Reaction

“…Imidazo[1,2-a]pyridines are a type of nitrogen-fused heterocycles have attracted interest over the past decade due to their widespread applications in medicinal chemistry and these scaffolds are present in many commercially available drugs [1][2][3][4]. These heterocycles display very good luminescent properties and examples of this scaffold with applications in bioimaging (1) probe or chemosensor (2)(3) are been reported ( Figure 1) [5][6][7]. Electron-rich chromophores such as triphenylamine (TPA) has the capability of donating electrons and have extensively been exploited in the synthesis of organic π-type semiconductors.…”

Facile synthesis of 2-arylimidazo[1,2-a]pyridines catalysed by DBU in aqueous ethanol

“…Owing to the importance of this heterocyclic motif, different methods for its synthesis have been developed by different groups. The important approaches adopted are: (i) condensation of 2-aminopyridines with α-diazoketones [19], α-haloketones [20], α-tosyloxyketones [21], alkynyl(phenyl)iodonium salts [22], 1-bromo-2-phenylacetylene/1,1-dibromo-2-phenylethene [23], arylglyoxal hydrates [24], propargyl alcohol [25] under different reaction conditions, (ii) tandem reactions such as reaction between Morita-Baylis-Hillman (MBH) acetates of nitroalkenes and 2-aminopyridines [26], tandem coupling between 2-aminopyridine and nitroolefin [27,28] and (iii) multicomponent reaction of 2-aminopyridine, carbonyls with nitroalkane [29,30], trimethylsilyl cyanide [31], isonitrile [32,33], imidazoline-2,4,5-trione [34,35], alkynes [36,37], alkyne carboxylic acid [38] and urea derivatives [39] (figure 2). In recent times, there have been reports of copper-catalysed synthesis for imidazo[1,2-a]pyridine derivatives also [41][42][43][44][45].…”

Environment-Friendly Protocol for the Chlorination of Imidazoheterocycles by Chloramine-T

“…1,2 This scaffold is also successfully employed in the field of material science. 3,4 As a consequence, different processes have been reported for the synthesis and functionalization of imidazopyridine derivatives. 5−15 Many efficient methods of important functionalization and various synthetic strategies of imidazo[1,2- a ]pyridines from readily available starting materials have been also developed by our group.…”