Boron tribromide → 4-Chloro-2-hydroxyphenyl-1-methyl-6-trifluoromethyluracil

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Reaction Steps

41.0 g (122.5 mmol) of 3-(4-chloro-2-methoxyphenyl)-1-methyl-6-trifluoromethyluracil was dissolved in 1000 ml of dichloromethane, and 470 ml (470.8 mmol) of boron tribromide (1.0M dichloromethane solution) was dropwise added at from -10° C. to -5° C. After stirring at room temperature for 3 hours, the reaction solution was poured into ice water and neutralized with sodium hydrogencarbonate. It was extracted with dichloromethane. The organic layer was washed sequentially with water and a saturated sodium chloride aqueous solution and then, dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure. Then, the obtained crude crystals were washed with isopropyl ether to obtain 27.6 g (yield: 70.3%) of the desired product as white crystals. Melting point: 198-202° C.

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