Sodium Carbonate → 4-Bromo-2-(2,6-dichlorophenyl)-7-methyl-2H-pyrazolo[4,3-c]pyridine

HRID 626777Notes

Reaction equation

O(Br)[Br:2].[P+5].[Cl:5][C:6]1[CH:11]=[CH:10][CH:9]=[C:8]([Cl:12])[C:7]=1[N:13]1[CH:23]=[C:16]2[CH:17]=[N+:18]([O-])[CH:19]=[C:20]([CH3:21])[C:15]2=[N:14]1.C(=O)([O-])[O-].[Na+].[Na+]>ClCCCl>[Br:2][C:17]1[C:16]2=[CH:23][N:13]([C:7]3[C:6]([Cl:5])=[CH:11][CH:10]=[CH:9][C:8]=3[Cl:12])[N:14]=[C:15]2[C:20]([CH3:21])=[CH:19][N:18]=1

Participants

Conditions

Temperature: 0 °C

Procedure

Phosphorus(V) oxybromide (921 mg, 3.43 mmol) was slowly added to a suspension of 2-(2,6-dichlorophenyl)-7-methyl-2H-pyrazolo[4,3-c]pyridine-5-oxide (404 mg, 1.37 mmol) in DCE (9.0 mL) at 0° C., under an atmosphere of nitrogen. The reaction mixture was stirred at 0° C. for 30 minutes and then at room temperature overnight. The orange suspension was poured onto saturated aqueous sodium carbonate solution and was stirred for 10 minutes. This was extracted with DCM and the organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered 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 (185 mg, 38% yield). 1H NMR (300 MHz, DMSO-d6): δ 9.20 (s, 1H), 7.90-7.89 (m, 1H), 7.84-7.80 (m, 2H), 7.76-7.72 (m, 1H), 2.45 (d, J=1.2 Hz, 3H).

Workup

customat room temperature
customovernight
stirringwas stirred for 10 minutes
extractionThis was extracted with DCM
washthe organic layer was washed with brine
dry with materialdried over anhydrous magnesium sulfate
filtrationfiltered
concentrationconcentrated under reduced pressure
customThe residue was purified by silica gel flash chromatography (0-30% ethyl acetate in cyclohexane)

Sources & evidence

ORD record: ord-59349fb57e034ea49f76029206146eba
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09309240B2

Reaction notes

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