반응 #792174
ord-6e206051077f4a788d0f3e7729061cd6
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시약
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후처리
- 1기타The reaction mixture thinned to form a pale green, nearly clear solution
- 2기타to form a pale yellow suspension
- 3온도the reaction mixture was heated
- 4온도at gentle reflux for 3.5 hours
- 5온도After cooling
- 6기타a precipitate of white solid was removed by filtration
- 7workup.ADDITIONThe filtrate was diluted with water (400 mL)
- 8추출extracted three times with ethyl ether (700 mL total)
- 9기타precipitation of an off-white solid (3.75 g), which
- 10여과was collected by filtration
- 11농축The ether mother liquor was further concentrated
실험 절차
To a suspension of ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate (i.e. product of Example 12, Step A) (27 g, 100 mmol) stirred in dry acetonitrile (200 mL) was added sulfuric acid (20 g, 200 mmol) in one portion. The reaction mixture thinned to form a pale green, nearly clear solution before thickening again to form a pale yellow suspension. Potassium persulfate (33 g, 120 mmol) was added in one portion, and then the reaction mixture was heated at gentle reflux for 3.5 hours. After cooling using an ice bath, a precipitate of white solid was removed by filtration and discarded. The filtrate was diluted with water (400 mL) and then extracted three times with ethyl ether (700 mL total). Concentration of the combined ether extracts to a reduced volume (75 mL) caused precipitation of an off-white solid (3.75 g), which was collected by filtration. The ether mother liquor was further concentrated to yield a second crop of an off-white precipitate (4.2 g), which was also collected by filtration. An off-white solid also precipitated from the aqueous phase; this solid (4.5 g) was collected by filtration to provide a combined total of 12.45 g of the title compound.