Diisopropylethylamine → 2-(1-(tert-Butyldimethylsilyl)-2-oxopyrrolidin-3-yl)-N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)-N-ethylacetamide

Temperature

-78 °C

DIPEA (0.629 mL, 4.41 mmol) was dissolved in THF (20 mL) and cooled to about −78° C. n-Butylithium (1.77 mL, 4.41 mmol) was then added, and the reaction mixture was warmed to about 0° C. for 10 minutes, then re-cooled to about −78° C. Then, 1-(tert-butyldimethylsilyl)pyrrolidin-2-one (0.800 g, 4.01 mmol) was added, and the reaction mixture was warmed to 23° C. and stirred for 1 hour. The reaction was then re -chilled to −78° C., and 2-chloro-N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)-N-ethylacetamide (0.600 g, 2.01 mmol) was then added dropwise as a solution in THF (3 mL). The reaction mixture was stirred cold for 30 minutes, then was allowed to slowly warm to room temperature. After 1 hour, the reaction was quenched with a NH4Cl solution and extracted with diethyl ether. The organics were washed with brine, dried over Na2SO4, and concentrated. The resulting oil was purified by flash column chromatography using 0-40% acetone/hexanes as eluent provided the intermediate 2-(1-(tert -butyldimethylsilyl)-2-oxopyrrolidin-3-yl)-N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)-N-ethylacetamide (0.604 g, 1.31 mmol). 1H NMR analysis indicated a mixture of molecules present favoring the desired product of about 5:1 over main byproduct. The mixture carried through to the deprotection step without further purification. 2-(1-(tert-Butyldimethylsilyl)-2-oxopyrrolidin-3-yl)-N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)-N-ethylacetamide (0.604 g, 1.31 mmol) was dissolved in THF (13 mL) and added was tetrabutylammonium fluoride (TBAF, 1.96 mL, 1.96 mmol). The reaction mixture was stirred for 30 minutes. The reaction product was concentrated onto CELITE® and purified by flash column chromatography using 40-100% acetone/hexanes as eluent providing the title compound (0.204 g, 30% over 2 steps).

1. additionwas then added
2. temperaturethe reaction mixture was warmed to about 0° C. for 10 minutes
3. temperaturere-cooled to about −78° C
4. temperaturethe reaction mixture was warmed to 23° C.
5. stirringThe reaction mixture was stirred cold for 30 minutes
6. temperatureto slowly warm to room temperature
7. waitAfter 1 hour
8. customthe reaction was quenched with a NH4Cl solution
9. extractionextracted with diethyl ether
10. washThe organics were washed with brine
11. dry with materialdried over Na2SO4
12. concentrationconcentrated
13. customThe resulting oil was purified by flash column chromatography

ORD record

ord-aae1d24df895410eaceb1e841a1481b6

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09295260B2