ChemInform Abstract: Synthesis of Imidazo[1,2‐a]pyridines via Three‐Component Reaction of 2‐Aminopyridines, Aldehydes and Alkynes.

Abstract

Synthesis of Imidazo[1,2-a]pyridines via Three-Component Reaction of 2-Aminopyridines, Aldehydes and Alkynes. -The novel Cu-catalyzed approach tolerates a variety of functionalities at the substrates. However, in some cases no transformation is possible. -(LIU, P.; FANG, L.-S.; LEI*, X.; LIN, G.-Q.; Tetrahedron Lett. 51 (2010) 35, 4605-4608,

One-Pot Synthesis of 2-Phenylimidazo[1,2-α]pyridines from Acetophenone, [Bmim]Br3 and 2-Aminopyridine under Solvent-Free Conditions

“…Various methods have been reported for the synthesis of substituted imidazo[1,2-a]pyridines. The most important approaches embrace [ 20 ]: (1) condensation of 2-aminopyridine with α-halocarbonyl compounds [ 21 , 22 , 23 , 24 ], (2) one-pot condensations of isocyanide, aldehydes, and 2-aminopyridines [ 25 , 26 , 27 ], and (3) three-component reactions of 2-aminopyridines, aldehydes, and alkynes [ 28 , 29 , 30 ]. Although new methods are being published continuously, the synthesis of imidazo[1,2-α]pyridines using 2-aminopyridines with α-haloketones and α-haloaldehydes is still the most popular [ 31 , 32 ].…”