[F:1][CH:2]([F:13])[O:3][C:4]1[CH:9]=[C:8]([OH:10])[N:7]=[C:6]([S:11][CH3:12])[N:5]=1.O.O1CCOCC1.Cl[CH:22]([F:24])[F:23]>[OH-].[K+].C1OCCOCCOCCOCCOCCOC1>[F:13][CH:2]([F:1])[O:3][C:4]1[CH:9]=[C:8]([O:10][CH:22]([F:24])[F:23])[N:7]=[C:6]([S:11][CH3:12])[N:5]=1
14.0 g (0.067 mole) of 4-difluoromethoxy-6-hydroxy-2-methylthiopyrimidine are suspended in 18 ml of 50% potassium hydroxide solution, 10 ml of water and 160 ml of dioxane. After the addition of 0.5 g of 18-crown-6, the reaction mixture is heated to 40° C., and 20 g of chlorodifluoromethane are subsequently introduced over 5 hours. The aqueous phase is then separated and the organic phase is distilled under a high vacuum, affording 15.0 g (86.4% of theory) of 4,6-bis-difluoromethoxy-2-methylthiopyrimidine with a boiling point of 63° C./0.06 mbar. The substance melts at 46°-48° C.
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