Methyl 4-Fluoro-2-{1H-pyrrolo[2,3-b]pyridin-5-yloxy}benzoate is prepared by the reaction of 5-Hydroxy-7-azaindole and Methyl 2,4-difluorobenzoate
. The specific synthesis steps are as follows:
To a three-necked flask was added 100 g of 5-hydroxy-7-azaindole (746 mmol), 141 g of methyl 2,4-difluorobenzoate(821 mmol), 237 g of potassium phosphate (1.12 mol) and 500 mL of diethylene glycol dimethyl Ether, 110 ° C for 24 h (HPLC to monitor 5-hydroxy-7-azaindole).The reaction solution was concentrated to dryness, and 2L of ethyl acetate and 2 L of water were added. The organic phase was separated,dried over anhydrous sodium sulfate, and concentrated to dry crude.The crude product was heated to reflux with 1260 mL of ethyl acetate. The mixture was slowly added dropwise to a solution of 1260 mL ofpetroleum ether. After 1 h of dropping, the mixture was stirred for 1 h, slowly cooled to 25 ° C, filtered and dried to give163g of pale white solidRate of 76.5percent.HPLC purity 98percent.