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

Temperatur

-78 °C

To a mixture of tert-butyl(6-methoxypyrazolo[5,1-b][1,3]thiazol-7-yl)carbamate (16.5 g, 61.4 mmol) and THF (410 mL) was added n-butyllithium (2.77 M n-hexane solution: 62.1 mL, 172 mmol) while stirring at −78° C. After stirring the mixture at −78° C. for 40 minutes, 1,2-dibromotetrafluoroethane (10.2 mL, 86 mmol) was added, and the mixture was stirred for two hours while warming to mom temperature. A saturated aqueous solution of ammonium chloride and ethyl acetate were added to the mixture, and then acetic acid was added so that the mixture became weakly acidic. After thoroughly shaking the mixture, the organic layer was separated and the organic layer was washed with brine and dried over anhydrous magnesium sulfate. The mixture was filtered, and then the solvent in the filtrate was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (a mixed solvent of n-heptane and ethyl acetate: n-heptane/ethyl acetate=1/0 then 4/1) to obtain the title compound (14.3 g, 41.1 mmol).

1. stirringAfter stirring the mixture at −78° C. for 40 minutes
2. stirringthe mixture was stirred for two hours
3. temperaturewhile warming to mom temperature
4. stirringAfter thoroughly shaking the mixture
5. customthe organic layer was separated
6. washthe organic layer was washed with brine
7. dry with materialdried over anhydrous magnesium sulfate
8. filtrationThe mixture was filtered
9. distillationthe solvent in the filtrate was distilled off under reduced pressure
10. customThe residue was purified by silica gel column chromatography (a mixed solvent of n-heptane and ethyl acetate

ORD-Eintrag

ord-31cb3001a9bc4f4ca494d02442e6e28e

Quelldatensatz

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08530504B2