5-Bromo-2-chloropyrimidine

Description5-Bromo-2-chloropyrimidine is a halogenated pyrimidine analogue containing chloro and bromo substituents at positions 2 and 5 of the benzene ring structure. The compound is used as a pharmaceutical intermediate in the preparation of macitentan, an endothelin receptor antagonist drug for the treatment of pulmonary hypertension.

Uses5-Bromo-2-chloropyrimidine is applied as a pharmaceutical intermediate, in the synthesis of pharmaceutical goods such as inhibitors. It is also employed in the cross-coupling reactions of indium organometallics with 2,5-dihalopyrimidines.

Uses5-Bromo-2-chloropyrimidine is a intermediate in the synthesis of pharmaceutical goods such as inhibitors.

PreparationUnder nitrogen protection, 35 g (0.2 mol) of 2-hydroxy-5-bromopyrimidine, 61.3 g (0.4 mol) of phosphorus oxychloride, and 200 mL of toluene were added into the reaction flask. At 35 ℃, triethylamine 40.5g was added and then heated up at 80-85 ℃. Stir the reaction for 6 hours, sampling HPLC to detect the raw material (less than 2%), and lower the temperature. After concentrating the mixture under reduced pressure to remove most of the toluene and Phosphorus oxychloride, put the reaction solution into 10°C water, and adjust pH=8-9 with 20% sodium carbonate aqueous solution. Finally, 5-Bromo-2-chloropyrimidine was obtained after purification.