Piperidine → 6-ethynyl-N-phenylimidazo[1,2-a]pyridine-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

0.2 g of 6-iodo-N-phenylimidazo[1,2-a]pyridine-2-carboxamide (Intermediate 2), 156 μL of trimethylsilylacetylene, 20 mg of dichlorobis(triphenylphosphine)palladium and 2 mL of piperidine are placed in a 20 mL microwave tube. The mixture is heated for 15 minutes in a microwave machine set at 130° C. After cooling, the mixture is poured into 50 mL of saturated aqueous ammonium chloride solution. The resulting mixture is extracted twice with 70 mL of ethyl ether. The combined organic phases are separated out by settling, dried and concentrated to dryness under reduced pressure. The residue is taken up in 4 mL of a 1M solution of tetrabutylammonium fluoride in THF and stirred for 16 hours at 25° C. After evaporating the reaction medium to dryness, the residue is chromatographed on silica, eluting with a mixture of cyclohexane and ethyl acetate (gradient from 0 to 35%) to give 30 mg of 6-ethynyl-N-phenylimidazo[1,2-a]pyridine-2-carboxamide in the form of a beige-coloured solid.

Provenance & Evidence