2-Amino-6-bromopyridine → 6-(6-aminopyrid-2-yl)-N-phenylimidazo[1,2-a]pyridine-2-carboxamide

Participants

Reaction Steps

236 mg of 6-trimethylstannyl-N-phenylimidazo[1,2-a]pyridine-2-carboxamide (Intermediate 4), 413 mg of 6-bromopyrid-2-ylamine, 95 mg of tetrakis(triphenylphosphine)palladium and 4 mL of N,N-dimethylformamide are placed in a microwave tube. The reaction mixture is heated for 45 minutes in a microwave machine set at 150° C. and concentrated to dryness. The residue is chromatographed on a silica cartridge, eluting with a mixture of dichloromethane and ethyl acetate. The fractions containing the expected product are combined and evaporated to dryness under reduced pressure to give 147 mg of 6-(6-aminopyrid-2-yl)-N-phenylimidazo[1,2-a]pyridine-2-carboxamide in the form of a yellow solid, which product is taken up in a mixture of dioxane and methanol and treated with 112 μL of a 4 M solution of hydrogen chloride in dioxane. After stirring for 1 hour at room temperature, the precipitate is filtered off by suction, washed with dioxane and dried to give 156 mg of 6-(6-aminopyrid-2-yl)-N-phenylimidazo[1,2-a]pyridine-2-carboxamide hydrochloride (1:1) in the form of a pale yellow solid.

Provenance & Evidence