Реакция #69542

Уравнение реакции

ammonium chloride

(6-ethoxy-pyrazolo[5,1-b][1,3]thiazol-7-yl)-carbamic acid tert-butyl ester

n-butyllithium

1,2-dibromotetrafluoroethane

→

title compound

Выход 62.3%

(3-Bromo-6-ethoxy-pyrazolo[5,1-b][1,3]thiazol-7-yl)-carbamic acid tert-butyl ester

Выход 62.3%

Растворители

n-hexane

THF

acetic acid

Условия реакции

Обработка

1. 1
   workup.STIRRINGThe mixture was stirred at −78° C. for one hour
2. 2
   workup.STIRRINGthe mixture was stirred
3. 3
   Температураwhile heating to room temperature for three hours
4. 4
   Экстракцияthe mixture was extracted with ethyl acetate
5. 5
   Промывкаwashed with brine
6. 6
   Сушкаdried over magnesium sulfate
7. 7
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
8. 8
   ДругоеThe residue was purified by medium pressure silica gel column chromatography (n-heptane/ethyl acetate

Методика

To a THF (150 mL) solution of (6-ethoxy-pyrazolo[5,1-b][1,3]thiazol-7-yl)-carbamic acid tert-butyl ester (16.5 g, 61.4 mmol), was added a 2.77M n-hexane solution of n-butyllithium (15.9 mL, 44 mmol) while stirring at −78° C. The mixture was stirred at −78° C. for one hour, and then 1,2-dibromotetrafluoroethane (2.61 mL, 22 mmol) was added, and the mixture was stirred while heating to room temperature for three hours. A saturated aqueous solution of ammonium chloride was added and acetic acid was added, and the mixture was extracted with ethyl acetate and washed with brine, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by medium pressure silica gel column chromatography (n-heptane/ethyl acetate: 0% then 30%) to obtain 4.95 g (13.7 mmol) of the title compound.

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