Acetic Acid → 2,5-Dimethoxy-4-cyanoaminopyrimidine

To a 100 mL three-neck round bottom flask were added sequentially 7.8 g (121.53 mmol)) of sodium hydrogen cyanamide and then 34.2 g of N-methyl-2-pyrrolidinone (NMP) in one portion, and the slurry mixture was cooled in an ambient temperature water bath. To this mixture was added 10.0 g (54.99 mmol) of 96% 4-chloro-2,5-dimethoxypyrimidine (1; CDMP) in one portion. The mixture was allowed to stir at ambient temperature (<20° C.). After 48 hours (h), 3.78 g (62.95 mmol) of glacial acetic acid was added in one portion and the internal pot temperature rose from 19° C. to 23° C. This reaction slurry was poured over 85 g of crushed ice and the ice was allowed to melt. To this mixture was added 10 g of sodium chloride. The mixture was allowed to stand for 16 minutes (min). Once melted, the cold slurry was suction filtered and the filter cake was washed with two 20-mL portions of water and a final 10 mL water wash. The wet cake transferred to a drying dish and allowed to air dry for 48 h to give 6.78 g (98.8% pure by NMR assay using benzyl acetate) of 2,5-dimethoxy-4-cyanoaminopyrimidine (2) as a light yellow solid in 68% yield. 1H and 13C NMR spectra were identical to that reported in Example 1.