反应详情

Ethylacetamide 3 (260 g, 1 mol) and 3-amino-4-cyanopyrazole 4 (108 g, 1 mol) were dissolved in a mixture of water (7 L) and ethanol (4 L). Eighty five percent aqueous phosphoric acid (67 ml, 1 mol) was added and the mixture was stirred at room temperature for 8 h. The reaction mixture was then cooled to 5° C. and the crystalline product that formed was collected, washed with water and dried at 60° C. to afford zaleplon (275 g, 90.2%) which was 99.36 pure by HPLC and contained 0.21% regioisomer 5.

1. temperatureThe reaction mixture was then cooled to 5° C.
2. customthe crystalline product that formed
3. customwas collected
4. washwashed with water
5. customdried at 60° C.