Yield:213265-83-9 98%

Reaction Conditions:

with trichlorophosphate in N,N-dimethyl-aniline at 110; for 6 h;Product distribution / selectivity;

Steps:

1.2
Method BTo a 2 L three necked round bottom flask containing 5-fluoropyrimidine-4,6-diol(276.459 g, 2.125 mol) was added at room temperature slowly phosphoryl chloride (0.593 L, 6.376 mol) to form a slurry. To this slurry was added N,N-dimethylaniline (81 mL, 0.638 mol) very slowly using an addition funnel (exothermic) and the reaction was continued for 6 h at 110 °C. After 6 h, the reaction mixture was cooled to room temperature and slowly added into brine and ice (2 L) with stirring. The aqueous layer (red) was extracted with DCM (2 x 2 L). The combined organic layers were washed with cold 6 Ν HC1 (honey brown) (2 x 1 L) and washed with sat NaHC0₃ (1 L). The organic layer was dried (Na₂S0₄), filtered by vacuum filtration through a glass fiber paper and solvent was removed under reduced pressure (no heat) to give 4,6-dichloro-5-fluoropyrimidine (CASNo.213265-83-9, 347.9 g, 2.084 mol, 98% yield) as an amber oil. NMR showed the oil contained traces of DCM. 4,6-Dichloro-5-fluoropyrimidine (420 g, 2.515 mol) was distilled by vacuum distillation to give 4,6-dichloro-5-fluoropyrimidine (332.574 g, 1.992 mol, 79% yield) as a colorless oil. The product solidified in the flask at -78 °C and melts when brought to room temperature. Conditions for distillation: Oil Bath: 100 °C; Product boiling temp: 35 °C; Pressure: 1 Torr. ^lU NMR (400 MHz, DMSO-i?) δ ppm 8.8 (s, 1H).

References:

ARENA PHARMACEUTICALS, INC.;JONES, Robert M.;LEHMANN, Juerg;CHEN, Weichao;EDWARDS, Jeffrey;MARQUEZ, Glen;MORGAN, Michael E.;SADEQUE, Abu J.M. WO2012/40279, 2012, A1 Location in patent:Page/Page column 86

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