2,4-Dichloro-5-(trifluoromethyl)pyrimidine → 4-Chloro-2-[5-(dimethylphosphoryl)-3-methoxypyrazin-2-yl]-5-(trifluoromethyl)pyrimidine

A suspension of 5-(dimethylphosphoryl)-3-methoxypyrazin-2-amine (prepared in Example 33: 2.2 mmol) in 15 mL of N,N-Dimethylacetamide and 3.6 mL of Diisopropylethylamine, is allowed to stirred at room temperature for 15 minutes until a clear solution is obtained. 2,4-Dichloro-5-(trifluoromethyl)pyrimidine (5.7 g, 2.6 mmol) is added in four portions over 5 minutes. The reaction mixture is stirred at 60 degrees for 1 hour. The reaction mixture is cooled to room temperature and filtered to obtain a white solid. The white solid is washed with 50 mL of water three times and followed by 50 mL of Ethyl ether three times. The white solid is dried under vacuum to yield 4-chloro-2-[5-(dimethylphosphoryl)-3-methoxypyrazin-2-yl]-5-(trifluoromethyl)pyrimidine.