反应详情

Water (500 ml) was added to the above crude 4-ethoxycarbonylethyl-1-formylpiperazine (114 g) to dissolve and thereto sodium tungstate dihydrate (7.25 g) was added. Thereto 31% aqueous hydrogen peroxide solution (82 ml) was added dropwise at 30° to 35° C. and the mixture was stirred at the same temperature for 1 hour. After further stirring the mixture at room temperature for 3 hours and then with heating at 50° to 55° C. for 5 hours, ethyl acetate (300 ml) was added and the mixture was shaken. The aqueous layer was separated and water was distilled off under reduced pressure to give black-brown oil, which was then purified by silica-gel column chromatography (silica gel 2 Kg, eluent: chloroform - methanol=10:1) and recrystallized from ethyl acetate to give 1-formyl-4-hydroxypiperazine (38.2 g), m.p. 118°-124° C.

1. dissolutionto dissolve
2. stirringAfter further stirring the mixture at room temperature for 3 hours
3. temperaturewith heating at 50° to 55° C. for 5 hours
4. stirringthe mixture was shaken
5. customThe aqueous layer was separated
6. distillationwater was distilled off under reduced pressure
7. customto give black-brown oil, which
8. customwas then purified by silica-gel column chromatography (silica gel 2 Kg, eluent: chloroform - methanol=10:1)
9. customrecrystallized from ethyl acetate