2802-62-2

a) Preparation of 4,6-difluoropyrimidine (STR13): 4,6-dichloropyrimidine (223.5 g, 1.5 mol), potassium fluoride (279.6 g, 4.8 mol) and tetrabutylammonium bromide (6.0 g, 0.0186 mol) were dissolved in cyclobutanesulfone (1 L). The reaction mixture was heated at 180-190 °C for 3.5 h followed by distillation to afford the target product 4,6-difluoropyrimidine as a white liquid (115 g, 66% yield).

[1] Patent: US5977363, 1999, A
[2] Patent: US5977363, 1999, A
[3] Patent: EP794177, 1997, A1
[4] Patent: EP794177, 1997, A1
[5] Chemistry Letters, 1993, # 3, p. 509 - 512