Phosphorus oxybromide → 4-Bromo-2-(2-chloro-6-fluorophenyl)-2H-pyrazolo[4,3-c]pyridine

HRID 626679Notes

Reaction equation

[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([F:8])[C:3]=1[N:9]1[CH:18]=[C:12]2[CH:13]=[N+:14]([O-])[CH:15]=[CH:16][C:11]2=[N:10]1.P(Br)(Br)([Br:21])=O>ClCCCl.C(Cl)Cl>[Br:21][C:13]1[C:12]2=[CH:18][N:9]([C:3]3[C:4]([F:8])=[CH:5][CH:6]=[CH:7][C:2]=3[Cl:1])[N:10]=[C:11]2[CH:16]=[CH:15][N:14]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a suspension of 2-(2-chloro-6-fluorophenyl)-2H-pyrazolo[4,3-c]pyridine 5-oxide (740 mg, 2.8 mmol) in DCE (18 mL) at 0° C. was added phosphorus oxybromide (2.4 g, 8.4 mmol). The reaction mixture was stirred at 0° C. for 15 minutes, warmed to room temperature, and stirred for an additional 4.5 h. The resultant mixture was diluted with DCM, washed with sodium carbonate (sat. aq.) and then with brine. The organic phase was dried over anhydrous magnesium sulphate and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (0-30% ethyl acetate in cyclohexane) to afford the title compound as a white solid (230 mg, 25% yield). LCMS (Method C): RT=3.44 min, m/z: 327 [M+H+].

Workup

temperaturewarmed to room temperature
stirringstirred for an additional 4.5 h
washwashed with sodium carbonate (sat. aq.)
dry with materialThe organic phase was dried over anhydrous magnesium sulphate
concentrationconcentrated under reduced pressure
customThe residue was purified by silica gel flash chromatography (0-30% ethyl acetate in cyclohexane)

Sources & evidence

ORD record: ord-23d6266dc9b548af98fdbb3757fe0551
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09309240B2

Reaction notes

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