反应 #45446

反应方程式

sodium bicarbonate

5-bromo-2-hydroxy-benzaldehyde

hydroxylamine-O-sulfonic acid

→

desired product

5-bromo-1,2-benzisoxazole

溶剂

water

dichloromethane

ethanol

反应条件

后处理

1. 1
   workup.STIRRINGThe solution was stirred at 0° C. for 30 minutes
2. 2
   其他The organic layer was removed
3. 3
   萃取the aqueous layer was extracted with dichloromethane
4. 4
   workup.ADDITIONThe aqueous layer was treated with additional dichloromethane (50 mL)
5. 5
   workup.STIRRINGstirring
6. 6
   workup.WAITwas continued for one hour
7. 7
   其他The layers were separated
8. 8
   萃取the aqueous layer was extracted with dicloromethane
9. 9
   洗涤The combined organic layers were washed with brine
10. 10
    干燥dried (MgSO4)
11. 11
    浓缩concentrated
12. 12
    其他The concentrate was recrystallized from ethanol

实验过程

A solution of 5-bromo-2-hydroxy-benzaldehyde (2.0 g, 10 mmol) in ethanol (10 mL) at room temperature was treated with hydroxylamine-O-sulfonic acid (1.69 g, 15 mmol), stirred for 20 minutes, diluted with dichloromethane (50 mL), cooled to 0° C. and treated with a solution of sodium bicarbonate (3 g) in water (25 mL). The solution was stirred at 0° C. for 30 minutes. The organic layer was removed and the aqueous layer was extracted with dichloromethane. The aqueous layer was treated with additional dichloromethane (50 mL) and stirring was continued for one hour. The layers were separated and the aqueous layer was extracted with dicloromethane. The combined organic layers were washed with brine, dried (MgSO4) and concentrated. The concentrate was recrystallized from ethanol to give 970 mg (49%) yield of the desired product. MS (ESI(−)) m/e 195.9, 197.9 (M−H)−

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