Cesium carbonate → Ethyl 8-[(3,5-difluoropyridine-4-yl)methoxy]-2-methylimidazo[1,2-a]pyridine-3-carboxylate

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Reaction Conditions

Reaction Steps

At RT, 1.86 g of 4-(chloromethyl)-3,5-difluoropyridine (Example 115A, 9.1 mmol, 2.0 equivalent) and 4.44 g of caesium carbonate (13.6 mmol, 3 equivalent) were added to 1.0 g of ethyl 8-hydroxy-2-methylimidazo[1,2-a]pyridine-3-carboxylate (Example 3A, 4.54 mmol, 1.0 equivalent) in 100 ml of DMF, and the mixture was stirred at 60° C. for 1 h. The mixture was then diluted with 500 ml of water and extracted twice with in each case 300 ml of ethyl acetate. The combined organic phases were washed with 400 ml of saturated aqueous sodium chloride solution, dried over sodium sulphate and concentrated using a rotary evaporator. The residue obtained was purified on a silica gel column (mobile phase: cyclohexane/ethyl acetate 7:1 to 1:1). This gave 900 mg (54% of theory) and 200 mg (13% of theory; purity about 85%) of the title compound.

Provenance & Evidence