Cesium carbonate → 1-(3-methoxy-4-nitro-1H-pyrazol-1-yl)propan-2-ol

Temperature

60 °C

To a suspension of 3-methoxy-4-nitro-1H-pyrazole (2.00 g, 14.0 mmol, 1.00 eq) and cesium carbonate (13.7 g, 41.9 mmol, 3.0 eq) was added 1-bromo-2-propanol (2.70 mL, 22.4 mmol, 1.60 eq, 70% purity) and the reaction mixture was heated at 60° C. After 3.5 hr, an additional portion of 1-bromo-2-propanol (2.70 mL, 22.4 mmol, 1.60 eq, 70% purity) was added. After a further 12 hr, the reaction mixture was cooled to ambient temperature and diluted with water (100 mL) and EtOAc (50 mL). The layers were separated and the aqueous phase was extracted with EtOAc (4×50 mL). The combined organics were washed with water (50 mL) and brine (50 mL), dried (Na2SO4), concentrated, and purified via flash chromatography on silica gel eluting with a gradient of 0-50% EtOAc in heptane to give the title compound (945 mg, 34% yield) as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 8.09 (s, 1H), 4.32-4.22 (m, 1H), 4.06 (s, 3H), 4.05 (dd, J=5.0, 13.0 Hz, 1H), 3.87 (dd, J=8.0, 13.0 Hz, 1H), 2.60 (br. s., 1H), 1.29 (d, J=6.4 Hz, 3H). m/z (APCI+) for C7H12N3O4 201.9 (M+H)+.

1. waitAfter a further 12 hr
2. temperaturethe reaction mixture was cooled to ambient temperature
3. customThe layers were separated
4. extractionthe aqueous phase was extracted with EtOAc (4×50 mL)
5. washThe combined organics were washed with water (50 mL) and brine (50 mL)
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated
8. custompurified via flash chromatography on silica gel eluting with a gradient of 0-50% EtOAc in heptane

ORD record

ord-57c626cf8a4b4d10b285302dcbec5ee2

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09290496B2