Propylene Oxide → 1-(3-Nitro-pyrazol-1-yl)-propan-2-ol

Temperature

100 °C

A solution of 3-nitro-1H-pyrazole (prepared in Example 3, 400 mg, 3.54 mmol) in N,N-dimethylformamide (5 mL) was treated with solid potassium carbonate (734 mg, 5.31 mmol) and 2-methyl-oxirane (500 μL, 3.54 mmol) and placed in a sealed tube and heated at 100° C. for 1 h in an oil bath. After this time the reaction was cooled to 25° C. and diluted with water (30 mL) and extracted with ethyl acetate (3×20 mL). The organic layers were then combined and washed with saturated aqueous brine solution (2×20 mL) and then dried over sodium sulfate, filtered and concentrated in vacuo with silica gel (2 g) and purified by Biotage Flash Chromatography (40S column, Silica gel, 60% ethyl acetate/hexanes) to afford 1-(3-nitro-pyrazol-1-yl)-propan-2-ol (332 mg, 55%) as a clear colorless oil: ES-HRMS m/e calcd for C6H9N3O3 (M+H)+ 172.0717, observed 172.0716; 36730-255 1H NMR (300 MHz, CDCl3) δ ppm 1.28 (d, J=6.3 Hz, 3H, CH3), 2.15 (br. s., 1H, OH), 4.03-4.13 (m, 1H, CH of CH2), 4.23-4.38 (m, 2H, OCH and CH of CH2), 6.91 (d, J=2.4 Hz, 1H, Ar), 7.56 (d, J=2.4 Hz, 1H, Ar).

1. customplaced in a sealed tube
2. temperatureAfter this time the reaction was cooled to 25° C.
3. extractionextracted with ethyl acetate (3×20 mL)
4. washwashed with saturated aqueous brine solution (2×20 mL)
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo with silica gel (2 g)
8. custompurified by Biotage Flash Chromatography (40S column, Silica gel, 60% ethyl acetate/hexanes)

ORD record

ord-3873cebbf4f34b4085ff0936b5b56044

Source dataset

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07935699B2