Реакция #45446

Уравнение реакции

sodium bicarbonate

5-bromo-2-hydroxy-benzaldehyde

hydroxylamine-O-sulfonic acid

→

desired product

5-bromo-1,2-benzisoxazole

Растворители

water

dichloromethane

ethanol

Условия реакции

Обработка

1. 1
   workup.STIRRINGThe solution was stirred at 0° C. for 30 minutes
2. 2
   ДругоеThe organic layer was removed
3. 3
   Экстракцияthe 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
   ДругоеThe layers were separated
8. 8
   Экстракцияthe aqueous layer was extracted with dicloromethane
9. 9
   ПромывкаThe combined organic layers were washed with brine
10. 10
    Сушкаdried (MgSO4)
11. 11
    Концентрированиеconcentrated
12. 12
    ДругоеThe concentrate was recrystallized from ethanol

Методика

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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