反应 #595338

反应方程式

sodium thiosulfate

ethyl 2-amino-1,3-oxazole-4-carboxylate

p-toluenesulfonic acid dihydrate

sodium nitrite

potassium iodide

sodium bicarbonate

→

Ethyl 2-iodo-1,3-oxazole-4-carboxylate

溶剂

acetonitrile

water

water

反应条件

后处理

1. 1
   温度after warming to RT, further overnight
2. 2
   萃取The aqueous phase is extracted three times with in each case 30 ml of ethyl acetate
3. 3
   干燥The combined organic phases are dried over magnesium sulfate
4. 4
   过滤After filtration
5. 5
   其他the solvent is removed on a rotary evaporator
6. 6
   其他The residue is purified by column chromatography on silica gel 60 (mobile phase gradient: cyclohexane/ethyl acetate 300:1→2:1)

实验过程

2.00 g (12.81 mmol) of ethyl 2-amino-1,3-oxazole-4-carboxylate are added to a solution of 8.00 g (38.43 mmol) of p-toluenesulfonic acid dihydrate in 48 ml of acetonitrile. The suspension is cooled to 0° C., and a solution of 1.77 g (25.62 mmol) sodium nitrite and 5.32 g (32.02 mmol) potassium iodide in 7.2 ml of water is then added. The mixture is stirred at 0° C. for 10 min and, after warming to RT, further overnight. The mixture is then diluted with 200 ml of water. By addition of 1 M aqueous sodium bicarbonate solution, the pH is adjusted to 9. 24 ml of 2 M sodium thiosulfate solution are then added. The aqueous phase is extracted three times with in each case 30 ml of ethyl acetate. The combined organic phases are dried over magnesium sulfate. After filtration, the solvent is removed on a rotary evaporator. The residue is purified by column chromatography on silica gel 60 (mobile phase gradient: cyclohexane/ethyl acetate 300:1→2:1).

来源