A soluton of 1,4-dihydro-2-methoxy-6-methyl-4-(3-nitrophenyl)-5-pyrimidinecarboxylic acid, 1-methylethyl ester (5.00 g, 15.0 mmol; see Example 2A) and triethylamine (5.88 g; 45.0 mmol) in dichloromethane (45 ml) at 0° C. under argon was treated via syringe with a 1.2M solution of phosgene in benzene (15.0 ml, 18.0 mmol). After stirring at 0° C. for 3.5 hours, the reaction was treated with concentrated ammonium hydroxide (1.52 ml, 22.5 mmol). After two hours at room temperature, the reaction was treated with more concentrated ammonium hydroxide (0.5 ml, 7.5 mmol) and stirred at room temperature overnight. The reaction was then diluted with dichloromethane and washed with water and saturated sodium chloride. The organic phase was concentrated and flash chromatographed to give the title compound as a brittle yellow foam (2.83 g).
