Cesium carbonate → 2,2,7-Trimethyl-2H-benzo[b][1,4]oxazin-3(4H)-one

온도

80 °C

6-Nitro-m-cresol (30.6 g) was dissolved in acetonitrile (400 ml), and thereto was added cesium carbonate (163.3 g), and the mixture was warmed to 80° C. To the mixture was added dropwise ethyl 2-bromoisobutyric acid (60 ml), and the mixture was stirred at 80° C. for 6 hours. To the mixture was added dropwise again ethyl 2-bromoisobutyric acid (60 ml), and the mixture was further stirred at 80° C. for 8 hours. The reaction solution was cooled to room temperature, and filtered through celite. The filtrate was concentrated under reduced pressure. The residue was dissolved in ethyl acetate, washed with water (twice) and saturated aqueous sodium chloride solution (once), and dried over sodium sulfate. The mixture was filtered, and concentrated under reduced pressure to give a crude product. The obtained crude product was dissolved in ethanol (100 ml), and added dropwise in to a solution of iron (90 g) in acetic acid (300 ml), wherein the suspension was previously and separately warmed to 75° C. After the addition was completed, the mixture was stirred at 80° C. for 5 hours, and filtered through celite. The filtrate was concentrated under reduced pressure, and the residue was dissolved in ethyl acetate, washed successively with water and saturated aqueous sodium hydrogen carbonate solution, dried over sodium sulfate, filtered and concentrated under reduced pressure to give a crude product. The obtained crude product was washed with hexane, and collected by filtration to give the title compound (32 g) as whited crystal.

1. stirringthe mixture was further stirred at 80° C. for 8 hours
2. temperatureThe reaction solution was cooled to room temperature
3. filtrationfiltered through celite
4. concentrationThe filtrate was concentrated under reduced pressure
5. dissolutionThe residue was dissolved in ethyl acetate
6. washwashed with water (twice) and saturated aqueous sodium chloride solution (once), and
7. dry with materialdried over sodium sulfate
8. filtrationThe mixture was filtered
9. concentrationconcentrated under reduced pressure
10. customto give a crude product
11. customThe obtained crude product
12. temperatureseparately warmed to 75° C
13. additionAfter the addition
14. stirringthe mixture was stirred at 80° C. for 5 hours
15. filtrationfiltered through celite
16. concentrationThe filtrate was concentrated under reduced pressure
17. dissolutionthe residue was dissolved in ethyl acetate
18. washwashed successively with water and saturated aqueous sodium hydrogen carbonate solution
19. dry with materialdried over sodium sulfate
20. filtrationfiltered
21. concentrationconcentrated under reduced pressure
22. customto give a crude product
23. customThe obtained crude product
24. washwas washed with hexane
25. filtrationcollected by filtration

ORD 기록

ord-a790464ba4d74b2fafc6d40ace5f6f02

출처 데이터셋

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US08658639B2