2-Bromo-4-methyl-1-nitrobenzene → 7-Bromo-5-methylindole

HRID 855279

Reaction equation

HRID 855279 reaction equation
[Br:1][C:2]1[CH:7]=[C:6]([CH3:8])[CH:5]=[CH:4][C:3]=1[N+:9]([O-])=O.[CH:12]([Mg]Br)=[CH2:13]>C1COCC1>[Br:1][C:2]1[CH:7]=[C:6]([CH3:8])[CH:5]=[C:4]2[C:3]=1[NH:9][CH:13]=[CH:12]2

Participants

4

Reactant 2

HCID 81670382-Bromo-4-methyl-1-nitrobenzeneHCID 178418507HCID 178418507, compound

Product 1

HCID 34033307-Bromo-5-methylindoleYield 52%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-65 °C

Procedure

3.3 g of 2-bromo-4-methyl-1-nitro-benzene (15 mmol) were dissolved in 200 ml THF and the solution was cooled to −65° C. Then 46 ml of a 1 molar solution of vinyl magnesium bromide in THF were added in a way, that the temperature of the reaction mixture stayed below −40° C. After 30 min at −40° C. the reaction was quenched with saturated ammonium chloride solution and was extracted with EtOAc. The combined organic phases were washed with brine and dried with magnesium sulfate. After filtration and evaporation of the solvent the crude product was purified by chromatography (silica gel; cyclohexane/EtOAc 4:1). 1.68 g (52%) of 7-bromo-5-methyl-indole were isolated as brown liquid. 1H NMR (DMSO-d6, 300 MHz): δ 2.36 (s, 3H), 6.45 (m, 1H), 7.14 (s, 1H), 7.34 (m, 2H), 11.16 (br s, 1H).

Workup

  1. customstayed below −40° C
  2. customAfter 30 min at −40° C. the reaction was quenched with saturated ammonium chloride solution
  3. extractionwas extracted with EtOAc
  4. washThe combined organic phases were washed with brine
  5. dry with materialdried with magnesium sulfate
  6. filtrationAfter filtration and evaporation of the solvent the crude product
  7. customwas purified by chromatography (silica gel; cyclohexane/EtOAc 4:1)

Sources & evidence

ORD record
ord-e92d560c46d44cc2bd5990d24e41e810
Source dataset
uspto-grants-2007_08
Patent number
US07259183B2

Linked notes

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