3.6 g (0.015 mol) of 2-methoxycarbonylbenzenesulfonyl isocyanate in 15 ml of 1,2-dichloroethane were added over the course of 15 minutes to a stirred mixture of 2.95 g (0.015 mol) of 2-amino-4-fluoro-6-trifluoromethoxypyrimidine and 100 ml of 1,2-dichloroethane at 25° C., and the mixture was stirred at 25° C. for 12 hours. The solution was concentrated under reduced pressure, and the residue was stirred with 1:1 ether/petroleum ether. Filtration with suction and drying yielded 4.8 g (73.3% of theory) of the title compound of melting point 157°-161° C.
