Reaktion #65388

Reaktionsgleichung

4-chlorobutyryl chloride

triethylamine

4-amino-3,4-dihydro-2,2-dimethyl-6-nitro-2H-1,4-benzoxazine

→

3,4-dihydro-2,2-dimethyl-4-(2-oxo-1-pyrrolidinyl)-6-nitro-2H-1,4-benzoxazine

Lösungsmittel

methylene chloride

water

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe solution was cooled on an ice bath
2. 2
   Extraktionextracted with chloroform
3. 3
   TrocknenThe organic layer was dried over anhydrous magnesium sulfate
4. 4
   Einengenconcentrated under reduced pressure
5. 5
   SonstigeThe concentrate was crystallized from ether
6. 6
   Sonstigeto give 0.43 g of crude crystals of 4-chloro-N-(3,4-dihydro-2,2-dimethyl-6-nitro- 2H-1,4-benzoxazin-4-yl)butyrylamide
7. 7
   SonstigeThe crude crystals were used without purification in the next reaction
8. 8
   workup.DISSOLUTION(4) In 8 ml of N,N-dimethylformamide was dissolved 0.41 g of the above amide
9. 9
   Temperaturthe solution was cooled on an ice bath
10. 10
    workup.ADDITIONThen, 0.14 g of potassium tert-butoxide was gradually added
11. 11
    Temperaturcooling for 1 hour
12. 12
    workup.ADDITIONafter which it was diluted with water
13. 13
    Extraktionextracted with ethyl acetate
14. 14
    WaschenThe organic layer was washed with saturated aqueous sodium chloride solution
15. 15
    Trocknendried over anhydrous magnesium sulfate
16. 16
    Filtrationfiltered
17. 17
    EinengenThe filtrate was concentrated under reduced pressure
18. 18
    Sonstigecrystallized from ether
19. 19
    SonstigeThe crude crystals were recrystallized from ethanol

Vorschrift

In 4 ml of methylene chloride was dissolved 0.35 g of 4-amino-3,4-dihydro-2,2-dimethyl-6-nitro-2H-1,4-benzoxazine and the solution was cooled on an ice bath. To this solution was added 0.16 g of triethylamine followed by dropwise addition of a solution of 0.18 ml of 4-chlorobutyryl chloride in 1.4 ml of methylene chloride. After 30 minutes, the reaction mixture was diluted with water and extracted with chloroform. The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The concentrate was crystallized from ether to give 0.43 g of crude crystals of 4-chloro-N-(3,4-dihydro-2,2-dimethyl-6-nitro- 2H-1,4-benzoxazin-4-yl)butyrylamide. The crude crystals were used without purification in the next reaction. (4) In 8 ml of N,N-dimethylformamide was dissolved 0.41 g of the above amide and the solution was cooled on an ice bath. Then, 0.14 g of potassium tert-butoxide was gradually added. The mixture was stirred with ice-cooling for 1 hour, after which it was diluted with water and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure and crystallized from ether. The crude crystals were recrystallized from ethanol to give 0.16 g of 3,4-dihydro-2,2-dimethyl-4-(2-oxo-1-pyrrolidinyl)-6-nitro-2H-1,4-benzoxazine.

Quelle