Synthesis
Part A: Synthesis of 5-fluoro-4,6-dihydroxy-2-methylpyrimidine. A methanolic solution of 25% sodium methanolate (0.84 mol) was diluted in 200 mL of methanol. To this solution, acetamidine hydrochloride (40 g, 0.42 mol) was added and white precipitate formation was observed. Subsequently, dimethyl fluoromalonate (70 g, 0.46 mol) was added. The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the solvent was removed by vacuum concentration to give a dry residue. The residue was redissolved in 300 mL of hot water. After the aqueous solution was cooled to room temperature, concentrated hydrochloric acid was slowly added and the pH was adjusted to about 5. The formation of fine white prismatic crystals was observed. Concentrated hydrochloric acid was continued to be added dropwise to pH 3 and then the crystals were collected by filtration. The crystals were washed with 1 M hydrochloric acid and dried under vacuum to afford 5-fluoro-4,6-dihydroxy-2-methylpyrimidine (65.5 g, yield >100%).LCMS analysis showed (M + H)+: 145.
References
[1] Patent: WO2009/61879, 2009, A1. Location in patent: Page/Page column 60-61
[2] Patent: WO2013/82388, 2013, A1. Location in patent: Page/Page column 66-67
