反应详情

Under argon, 105 g (270 mmol) of ethyl 8-(benzyloxy)-6-bromo-2-methylimidazo[1,2-a]pyridine-3-carboxylate Example 85A were suspended in 4.2 l of 1,4-dioxane, 135.4 g (539 mmol, purity 50%) of trimethylboroxine, 31.2 g (27 mmol) of tetrakis(triphenylphosphine)palladium(0) and 78.3 g (566 mmol) of potassium carbonate were added in succession and the mixture was stirred under reflux for 8 h. The reaction mixture was cooled to RT, the precipitate was filtered off over silica gel and the filtrate was concentrated. The residue was dissolved in dichloromethane and purified by silica gel chromatography (dichloromethane:ethyl acetate=9:1). This gave 74 g (84.6% of theory; purity 100%) of the target compound.

1. temperatureunder reflux for 8 h
2. filtrationthe precipitate was filtered off over silica gel
3. concentrationthe filtrate was concentrated
4. dissolutionThe residue was dissolved in dichloromethane
5. custompurified by silica gel chromatography (dichloromethane:ethyl acetate=9:1)