Thionyl Chloride → 1-(2-Bromoethyl)-5-(chloromethyl)-3-nitro-1H-pyrazole

Temperature

-5 °C

A 50-mL three-necked round-bottomed flask equipped with a nitrogen inlet and a reflux condenser was purged with nitrogen and charged with 296b (438 mg, 1.76 mmol) and chloroform (10 mL). The reaction was cooled to −5° C. using an ice/acetone bath and SOCl2 (628 mg, 5.28 mmol) was added portion-wise. The cooling bath was removed and the reaction was stirred at 70° C. for 3 h. After this time, the solvent was removed under reduced pressure. ethyl acetate was added to the residue and the resulting solution was cooled to −5° C. Saturated aqueous sodium bicarbonate (3 mL) was added until a pH of 8.5 was reached. The mixture was partitioned between ethyl acetate and water. The combined organic layer was washed with saturated aqueous sodium carbonate (2×5 mL), brine (10 mL), and dried over sodium sulfate. The drying agent was removed by filtration. The filtrate was concentrated under reduced pressure to afford 296c (284 mg, 60%).

1. customA 50-mL three-necked round-bottomed flask equipped with a nitrogen inlet and a reflux condenser
2. customwas purged with nitrogen
3. customThe cooling bath was removed
4. customAfter this time, the solvent was removed under reduced pressure
5. additionethyl acetate was added to the residue
6. temperaturethe resulting solution was cooled to −5° C
7. additionSaturated aqueous sodium bicarbonate (3 mL) was added until a pH of 8.5
8. customThe mixture was partitioned between ethyl acetate and water
9. washThe combined organic layer was washed with saturated aqueous sodium carbonate (2×5 mL), brine (10 mL)
10. dry with materialdried over sodium sulfate
11. customThe drying agent was removed by filtration
12. concentrationThe filtrate was concentrated under reduced pressure

ORD record

ord-67afc2e7717a480a9945c7e61c33ce1a

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09238655B2