Dichloromethane → Imidazo(1,2-a)pyridine

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Reaction Steps

In Scheme 3, 2,6-diaminopyridine 15 is reacted with an alpha halocarbonyl 16 to give the imidazo[1,2-a]pyridine 17. The resulting amino group can be reacted with a carboxylic acid 18 using a coupling reagent such as chloro-1,3 dimethyl-4,5-dihydro-3H imidazolium chloride in the presence of a base such as TEA in a solvent such as ACN or alternatively by reacting amine 17 with an acid chloride 18 at elevated temperature in a solvent such as dichloroethane to give compound 19. Alternatively, the 2,6-diaminopyridine 15 is reacted with acid 20 using a coupling agent such as, but not limited to, BOP or DMC in an organic solvent such as DCM or DMF in the presence of an organic base such as Hunig' s base. The resulting amide 21 is reacted with alpha halocarbonyl 22 to give the imidazo[1,2-a]pyridine 23.

Provenance & Evidence