56-05-3

56-09-7

56-05-3

The general procedure for the synthesis of 2-amino-4,6-dichloropyrimidine from 2-amino-4,6-dihydroxypyrimidine is as follows: in a four-necked flask equipped with a reflux condenser, 510 g of 2-amino-4,6-dihydroxypyrimidine (98% purity, 4 mol) and 1428 g of phosphorus triclosan (99% purity) were added, heated and stirred. 810 g of triethylamine (99% purity) was slowly added dropwise at 40 to 45 °C through a constant pressure dropping funnel. After the dropwise addition, the reaction temperature was raised to 85 to 90 °C and maintained at this temperature for 2 hours. The progress of the reaction was monitored by high performance liquid chromatography (HPLC) and the reaction was considered complete when the amount of 2-amino-4,6-dihydroxypyrimidine was less than 1%. Subsequently, 3000 g of toluene was added to the reaction mixture, cooled to 0-10°C, and 3000 g of ice-water mixture was added for low temperature hydrolysis. The mixture was then warmed to room temperature and left to stratify. The aqueous layer was extracted twice with 400 g of toluene, and the organic phases were combined and washed sequentially with aqueous sodium carbonate and water until neutral. The organic phase was concentrated and 1800 g of toluene was recovered to give 2668 g of highly concentrated toluene solution. The product was analyzed by HPLC, the purity was 96.8%, the content was 22.58% (external standard method), and the yield of crude product was 92%.