Cesium carbonate → 2-(2-{[tert-Butyl(dimethyl)silyl]oxy}ethyl)-3-ethyl-4-nitropyrazole-5-carboxamide

Temperatur

80 °C

A mixture of 3-ethyl-4-nitro-1H-pyrazole-5-carboxamide (WO, 9849166), (4.9 g, 26.6 mmol), cesium carbonate (21.0 g, 64.5 mmol) and (2-bromoethoxy)-tert-butyldimethylsilane (7.0 g, 29.0 mmol) in acetonitrile (400 ml) was stirred at 80° C. for 20 hours. The cooled mixture was concentrated under reduced pressure and the residue was partitioned between ethyl acetate (200 ml) and water (100 ml). The layers were separated, the organic phase washed with water (3×50 ml), dried (Na2SO4) and evaporated under reduced pressure. The crude product was purified by column chromatography on silica gel, using ethyl acetate as eluant, and repeated using an elution gradient of pentane:ethyl acetate (50:50 to 0:100), to give some of the desired compound.

1. concentrationThe cooled mixture was concentrated under reduced pressure
2. customthe residue was partitioned between ethyl acetate (200 ml) and water (100 ml)
3. customThe layers were separated
4. washthe organic phase washed with water (3×50 ml)
5. dry with materialdried (Na2SO4)
6. customevaporated under reduced pressure
7. customThe crude product was purified by column chromatography on silica gel

ORD-Eintrag

ord-e77d4e7f081842e0af2eed0630b013d8

Quelldatensatz

uspto-grants-2007_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07176311B2