Sulfuric Acid → 5-Bromo-3-[(2,6-difluorobenzyl)oxy]pyridine-2-amine

Participants

Reaction Conditions

Reaction Steps

32.6 g of 3-[(2,6-difluorobenzyl)oxy]pyridine-2-amine (Example 1A; 138 mmol, 1 equivalent) were suspended in 552 ml of 10% strength aqueous sulphuric acid, and the mixture was cooled to 0° C. 8.5 ml of bromine (165 mmol, 1.2 equivalents) were dissolved in 85 ml of acetic acid and then, over a period of 90 min, added dropwise to the ice-cooled reaction solution. After the dropwise addition had ended, the mixture was stirred at 0° C. for 90 min and then diluted with 600 ml of ethyl acetate, and the aqueous phase was separated off. The aqueous phase was re-extracted with ethyl acetate. The organic phases were combined, washed with saturated aqueous sodium bicarbonate solution, dried and concentrated. The residue was dissolved in dichloromethane and chromatographed on silica gel (petroleum ether/ethyl acetate gradient as mobile phase). This gave 24 g (55% of theory) of the title compound.

Provenance & Evidence