Реакция #1395

Уравнение реакции

sodium hydroxide

(R)-tert-leucinol

water

chloroformic acid ethyl ester

→

(R)-4-tert-butyl-2-oxazolidinone

Выход 80.0%

Растворители

toluene

Условия реакции

Обработка

1. 1
   ТемператураThe mixture was then heated to 60°-65° C. at pH 8.0
2. 2
   Другоеthe aqueous phase separated
3. 3
   Температураslowly heated
4. 4
   workup.ADDITIONafter the addition of 0.4 g finely granulated sodium hydroxide at 70° C
5. 5
   Другоеproduced during the reaction
6. 6
   Другоеwas separated from 70°-100° C
7. 7
   workup.ADDITIONwas added
8. 8
   Другоеthe aqueous phase separated
9. 9
   Температураwarm water which
10. 10
    Другоеwas separated again after a brief agitation at 65° C
11. 11
    workup.DISTILLATIONAfter distilling the organic phase on a water separator the phase
12. 12
    Концентрированиеwas concentrated to 120 ml
13. 13
    Фильтрацияfiltered hot
14. 14
    Температураslowly cooled off under agitation, during which the product
15. 15
    Другоеseparated in colorless crystals
16. 16
    ФильтрацияThese crystals were filtered off after 30 min agitation at 5° C.
17. 17
    Промывкаwashed with cold toluene
18. 18
    Другоеdried in a vacuum at 50° C

Методика

73 g (containing 0.25 mole (R)-tert-leucinol) of the filtrate cited in example 6 was taken up with 27 ml water and 200 ml toluene. 25 ml (0.26 mole) chloroformic acid ethyl ester were then added dropwise at 20°-25° C., during which the pH was maintained at 7-8.5 by the addition of 10 M sodium hydroxide solution. The mixture was then heated to 60°-65° C. at pH 8.0 and the aqueous phase separated. The toluene phase was dehydrated on a water separator under a slight vacuum and slowly heated after the addition of 0.4 g finely granulated sodium hydroxide at 70° C. A total of 40 ml distillate which contained the ethanol produced during the reaction was separated from 70°-100° C . After cooling of the batch to 65° C. a solution of 0.6 ml glacial acetic acid in 10 ml water was added, the mixture briefly agitated, the aqueous phase separated and the toluene phase compounded again with 15 ml warm water which was separated again after a brief agitation at 65° C. After distilling the organic phase on a water separator the phase was concentrated to 120 ml, filtered hot and slowly cooled off under agitation, during which the product separated in colorless crystals. These crystals were filtered off after 30 min agitation at 5° C., washed with cold toluene and dried in a vacuum at 50° C. 28.6 g (R)-4-tert-butyl-2-oxazolidinone (80% yield) was obtained. A 1H-NMR spectrum corroborated the structure of the product.

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