5-Bromo-2,4-Dimethoxypyrimidine is an important organic synthesis intermediate. It appears as white crystals or a white powder, soluble in organic solvents such as methanol, ethanol, toluene, and acetone. It has some solubility in hot water and forms salts in acids. It is widely used in the synthesis of sulfonylurea herbicides, such as nicosulfuron, pyrimisulfuron, bensulfuron-methyl, and pyrimisulfuron, with nicosulfuron being the most widely used herbicide.
Add 1 g (7.87 mmol) of 5-bromo-2,4-dihydroxypyrimidine, 30 ml of methanol, stirring, to a 50 ml flask and add a methanol solution of diazomethane dropwise at 20 C, until the yellow color of the solution no longer disappears.
until the yellow color of the solution no longer disappears. Stir at constant temperature (20) for 24h (be careful to add diazomethane ethanol solution to maintain the yellow color of the solution). The reaction is completed, concentrated under pressure, washed with saturated K2CO3, and extracted with ethyl acetate.
Ethyl acetate extraction, the organic layer was dried with anhydrous Na2SO4, concentrated, column chromatography (ethanol/hexane=1:1) to obtain 1g (6.77 ).
1 g (6.77 , 87%) of 5-bromo-2,4-dimethoxypyrimidine was obtained by column chromatography (ethanol/hexane=1:1).
