A solution of 2-(chloromethyl)-N-(butylaminocarbonyl)benzene sulfonamide (1.33 g, 4.38 mmol) and diazabicyclo[2.2.2]octane (5 mg) in xylene (12 ml) was heated at reflux and contacted in portions with phosgene (1.0 ml. condensed phase). After 2.0 hrs at reflux, the mixture was cooled to room temperature, decanted, and volatiles were removed to give 1.56 g of crude product. The IR spectrum of 2-(chloromethyl)benzenesulfonyl isocyanate featured a strong band at 2250 cm-1. The crude sulfonyl isocyanate was contacted with acetonitrile (10 ml) and 2-amino-4,6-dimethoxypyrimidine (0.68 g, 4.4 mmol) and stirred for 16 hrs. Filtration gave 1.18 g of white solid, mp 192°-193°. The sample was dissolved in 0.5N NaOH, filtered and pH adjusted to 6.5. The mixture was cooled and filtered and the solid washed with ice water and dried to give 0.90 g of white solid.
