Реакция #64361

Уравнение реакции

carbonyl diimidazole

sodium hydride

ammonium chloride

3,4-dihydro-2,2-dimethyl-6-nitro-2H-1-benzopyran-3-one

→

3-hydroxy-2,2-dimethyl-6-nitro-2H-1-benzopyran-4-carboxamide

Выход 46.8%

Растворители

triethylamine

N,N-dimethylformamide

Условия реакции

Обработка

1. 1
   Температураunder cooling with ice
2. 2
   workup.STIRRINGAfter stirring for 50 minutes
3. 3
   workup.STIRRINGthe mixture stirred for 1 hour
4. 4
   workup.STIRRINGby stirring at 5° C. for 12 hours
5. 5
   Промывкаthe mixture was washed with diethyl ether
6. 6
   Экстракцияextracted with a mixed solvent of ethyl acetate and diethyl ether
7. 7
   ПромывкаThe organic layer was washed with water
8. 8
   Другоеdried
9. 9
   ДругоеThe solvent was removed by distillation
10. 10
    Другоеthe residue was purified by silica gel column chromatography (developing solution: CH2Cl2 :MeOH=99:1)

Методика

To a mixture of 41.5 g of 3,4-dihydro-2,2-dimethyl-6-nitro-2H-1-benzopyran-3-one and 500 ml of dried N,N-dimethylformamide was slowly added 8.2 g of sodium hydride (60%) in a nitrogen stream while stirring under cooling with ice. After stirring for 50 minutes, 33.5 g of carbonyl diimidazole was added thereto and the mixture stirred for 1 hour. To the reaction mixture were added 11.2 g of ammonium chloride and 29 ml of triethylamine, followed by stirring at 5° C. for 12 hours and then at room temperature for 14 hours. Ice-water was added to the reaction mixture, and the mixture was washed with diethyl ether. The aqueous layer was made acidic with hydrochloric acid and extracted with a mixed solvent of ethyl acetate and diethyl ether. The organic layer was washed with water and dried. The solvent was removed by distillation, and the residue was purified by silica gel column chromatography (developing solution: CH2Cl2 :MeOH=99:1) to obtain 23.2 g of 3-hydroxy-2,2-dimethyl-6-nitro-2H-1-benzopyran-4-carboxamide represented by formula shown below.

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