Water → 3-Bromo-1-(dimethylsulfamoyl)pyrazole

Temperature

-78 °C

To a solution of N,N-dimethyl-1H-pyrazole-1-sulfonamide obtained in Step A (6.74 g) in tetrahydrofuran (75 mL) was added dropwise n-butyllithium hexane solution (1.3 M, 31.1 mL) over 15 min at −78° C. The reaction mixture was stirred at −78° C. for 15 min, and a solution of 1,2-dibromo-1,1,2,2-tetrachloroethane (13.8 g) in tetrahydrofuran (25 mL) was added dropwise thereto over 10 min. The reaction mixture was stirred at −78° C. for 15 min, and then at room temperature for 1 hr. The reaction mixture was poured into water, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (8.03 g).

1. waitover 10 min
2. stirringThe reaction mixture was stirred at −78° C. for 15 min
3. waitat room temperature for 1 hr
4. extractionthe mixture was extracted with ethyl acetate
5. washThe extract was washed with saturated brine
6. dry with materialdried over anhydrous sodium sulfate
7. customthe solvent was evaporated under reduced pressure
8. customThe residue was purified by silica gel column chromatography (ethyl acetate/hexane)

ORD record

ord-2c3fb9e3b8ed4e1da8f24bc4e87917f7

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09085578B2