反应详情

4.61 g of 85% phosphoric acid are added at 20°±3° C. to a solution of 18.55 g of the compound obtained in example 195 in 185 ml of methylethylketone. Water is removed by distillation under atmospheric pressure of the azeotrope methylethylketone/water. The mixture is progressively cooled to 20°±3° C. while stirring for 20 hours. The white crystals formed are filtered off, washed with methylethylketone and dried under vacuum to give 21 g of the expected product. DSC: endothermic peak centered at 185.5° C.

1. customWater is removed by distillation under atmospheric pressure of the azeotrope methylethylketone/water
2. temperatureThe mixture is progressively cooled to 20°±3° C.
3. customThe white crystals formed
4. filtrationare filtered off
5. washwashed with methylethylketone
6. customdried under vacuum