1H-Pyrazole,3-methyl-5-phenyl- → 4-bromo-3-methyl-5-phenyl-1H-pyrazole

Temperature

0 °C

To a solution of 5-methyl-3-phenyl-1H-pyrazole (8.0 g, 50.6 mmol) in dichloromethane (150 mL) was added bromine (8.08 g, 50.6 mmol) dropwise at 0° C. The reaction was stirred at 0° C. for 30 min and then at room temperature for 2 h before quenching with aqueous Na2SO3 (10% w/w, 10 mL). The organic solvent was removed and the aqueous phase was extracted with EtOAc, washed with brine, dried over MgSO4, and concentrated. The residue was purified by silica gel column chromatography to give the title compound as a yellow oil (9.5 g). LCMS m/z=236.9 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ ppm 2.26 (s, 3H), 7.30-7.57 (m, 5H), 13.12 (s, 1H).

1. customat room temperature for 2 h before quenching with aqueous Na2SO3 (10% w/w, 10 mL)
2. customThe organic solvent was removed
3. extractionthe aqueous phase was extracted with EtOAc
4. washwashed with brine
5. dry with materialdried over MgSO4
6. concentrationconcentrated
7. customThe residue was purified by silica gel column chromatography

ORD record

ord-b105ef04ca8c49d4aeb515493f6b96dd

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09012478B2