Hydrochloric Acid → 4,7-Dibromo-1H-indole

HRID 2361430Notes

Reaction equation

HRID 2361430 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][C:3]=1[N+:9]([O-])=O.C(=O)=O.[C:15](#N)[CH3:16].C([Mg]Br)=C.[NH4+].[Cl-].Cl>C1COCC1.CCOC(C)=O>[Br:8][C:5]1[CH:6]=[CH:7][C:2]([Br:1])=[C:3]2[C:4]=1[CH:15]=[CH:16][NH:9]2

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 25517Ammonium ChlorideHCID 770041,4-Dibromo-2-nitrobenzeneHCID 86587134Acetonitrile dry iceHCID 178418507HCID 178418507, compound

Product 1

HCID 187528584,7-Dibromo-1H-indoleYield 47%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
-40 °C

Procedure

To a solution of 1,4-dibromo-2-nitrobenzene (18 g, 64.1 mmol) in THF (200 mL) at −40° C. (dry ice-acetonitrile) was added slowly a solution of vinylmagnesium bromide (1.0 M in THF, 199 mL, 199 mmol). The resulting mixture was stirred at −40° C. for 1.5 h, then was then treated with saturated aqueous NH4Cl (500 mL) and stirred at room temperature for 1 h. HCl (1M) was added to adjust the pH to 7. EtOAc was added and the organic phase was separated, washed with brine, dried and concentrated. The residue was subjected to column chromatography on silica gel (330 g), eluting with EtOAc-hexane (5:95) to provide a light yellow oil which solidified on standing under vacuum. The desired product was obtained as a solid (8.35 g, 47% yield. LCMS showed one major peak with no ionization.

Workup

  1. stirringstirred at room temperature for 1 h
  2. customthe organic phase was separated
  3. washwashed with brine
  4. customdried
  5. concentrationconcentrated
  6. washeluting with EtOAc-hexane (5:95)
  7. customto provide a light yellow oil which

Sources & evidence

ORD record
ord-a5aee006fb77407c84420261c894f2bb
Source dataset
uspto-grants-2014_04
Patent number
US08685969B2

Reaction notes

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