反应详情

温度

100 °C

To a suspension of allyl 3,5-diamino-1H-pyrazole-4-carboxylate 3 (42.72 g, 234.5 mmol) in DMSO (270.8 mL)/Water (270.8 mL), was added p-TsOH hydrate (46.72 g, 245.6 mmol) and 3-(diisopropylamino)-2-fluoro-prop-2-enal (described in Tetrahedron Letters, 33(3), 357-60; 1992) (38.69 g, 223.3 mmol). The reaction mixture was heated to 100° C. for 3 h during which time a solid slowly precipitated out of solution. The orange suspension was allowed to cool down to RT overnight. The solid was filtered, washed with water and dried under vacuum to give allyl 2-amino-6-fluoro-pyrazolo[1,5-a]pyrimidine-3-carboxylate 4a as a sand solid (45.05 g, 85% yield).

1. customslowly precipitated out of solution
2. temperatureto cool down to RT overnight
3. filtrationThe solid was filtered
4. washwashed with water
5. customdried under vacuum