Cesium carbonate → 6-(6-benzyloxypyrid-2-yl)-N-phenylimidazo[1,2-a]pyridine-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a solution of 250 mg of 2-benzyloxy-6-bromopyridine in 12 mL of dioxane are added a solution of 1.234 g of caesium carbonate in 3 mL of water, 34.6 mg of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium and then 546 mg of N-phenyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)imidazo[1,2-a]pyridine-2-carboxamide hydrobromide (1:1). The mixture is heated at 110° C. for 2 hours 45 minutes, and then cooled and filtered. The solid is washed with a small amount of methanol and then with dichloromethane and is then taken up in 250 mL of boiling methanol containing 5 mL of trifluoroacetic acid. The insoluble matter is filtered off and washed with methanol and then with dichloromethane and the filtrate is concentrated to dryness under reduced pressure. The residue is chromatographed on a silica cartridge, eluting with a gradient of from 0 to 5% of methanol in dichloromethane. The fractions containing the pure expected product are combined and concentrated to dryness under reduced pressure to give 0.3 g of 6-(6-benzyloxypyrid-2-yl)-N-phenylimidazo[1,2-a]pyridine-2-carboxamide in the form of a white solid.

Provenance & Evidence