2,6-Dibromo-3-methoxy-5-nitropyridine → 5,7-Dibromo-4-methoxy-6-azaindole

HRID 987541Notes

Reaction equation

HRID 987541 reaction equation
[CH:1]([Mg]Br)=[CH2:2].[Br:5][C:6]1[C:11]([O:12][CH3:13])=[CH:10][C:9]([N+:14]([O-])=O)=[C:8]([Br:17])[N:7]=1>C1COCC1>[Br:5][C:6]1[C:11]([O:12][CH3:13])=[C:10]2[C:9](=[C:8]([Br:17])[N:7]=1)[NH:14][CH:2]=[CH:1]2

Participants

4

Reactant 2

HCID 127582082,6-Dibromo-3-methoxy-5-nitropyridineHCID 178418507HCID 178418507, compound

Product 1

HCID 224762675,7-Dibromo-4-methoxy-6-azaindoleYield 15.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-20 °C

Procedure

Vinylmagnesium bromide (0.85 M in THF, 97.7 mL, 83.0 mmol) was added over 30 min. to a stirring solution of 2,6-dibromo-3-methoxy-5-nitropyridine (7.4 g, 23.7 mmol) in THF (160 mL) at −75° C. The solution was stirred 1 h at −75° C., overnight at −20° C., recooled to −75° C. and quenched with saturated aqueous NH4Cl (˜100 mL). The reaction mixture was allowed to warm to rt, washed with brine (˜100 mL) and extracted with Et2O (150 mL) and CH2Cl2 (2×100 mL). The combined organics were dried (MgSO4), filtered and concentrated. The residue was purified by flash column chromatography (SiO2, 3:1 hexanes/EtOAc) to yield 5,7-dibromo-4-methoxy-6-azaindole 36 (1.10 g, 3.60 mmol, 15%) as a pale yellow solid.

Workup

  1. customrecooled to −75° C.
  2. customquenched with saturated aqueous NH4Cl (˜100 mL)
  3. temperatureto warm to rt
  4. washwashed with brine (˜100 mL)
  5. extractionextracted with Et2O (150 mL) and CH2Cl2 (2×100 mL)
  6. dry with materialThe combined organics were dried (MgSO4)
  7. filtrationfiltered
  8. concentrationconcentrated
  9. customThe residue was purified by flash column chromatography (SiO2, 3:1 hexanes/EtOAc)

Sources & evidence

ORD record
ord-0cbaef023bf64eacade32c822d05f91c
Source dataset
uspto-grants-2003_10
Patent number
US06632819B1

Reaction notes

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