Benzenesulfonyl chloride → 1-benzenesulfonyl-5-bromo-2-methyl-1H-indole

HRID 400610Notes

Reaction equation

HRID 400610 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6]([CH3:11])=[CH:5]2.[H-].[Na+].[H][H].[C:16]1([S:22](Cl)(=[O:24])=[O:23])[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1.[Cl-].[NH4+]>CN(C=O)C>[C:16]1([S:22]([N:7]2[C:8]3[C:4](=[CH:3][C:2]([Br:1])=[CH:10][CH:9]=3)[CH:5]=[C:6]2[CH3:11])(=[O:24])=[O:23])[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

7

Reactant 5

HCID 7369Benzenesulfonyl chlorideHCID 24758Sodium hydrideHCID 25517Ammonium ChlorideHCID 50039685-Bromo-2-methylindoleHCID 178418361HCID 178418361, compound

Product 1

HCID 152568981-benzenesulfonyl-5-bromo-2-methyl-1H-indoleYield 68.4%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 5-bromo-2-methyl-1H-indole (1.5 g, 7.14 mmol) in 10 mL of DMF was added 60% sodium hydride in mineral oil (189 mg, 7.9 mmol). Once hydrogen gas evolution ceased, the mixture stirred for 10 minutes and was then treated with 1 mL (7.83 mmol) of benzene sulfonyl chloride. The reaction was monitored by TLC (ethyl acetate-hexanes (5:95)) to afford a major new slightly less polar product than starting material. After 2 hours, the mixture was poured into 50 mL of saturated aqueous ammonium chloride solution and extracted with three 50 mL portions of ethyl acetate. The combined organic layers were washed with four 25 mL portions of brine, dried over magnesium sulfate, treated with activated carbon (NORIT A™), filtered through diatomaceous earth, and concentrated in vacuo. The residue was adsorbed onto silica gel and chromatographed on silica gel using ethyl acetate-hexanes (1:99, then 2:98, then 3:97) to afford 1.71 g (68.4% yield) of 1-benzenesulfonyl-5-bromo-2-methyl-1H-indole as a clear oil.

Workup

  1. customto afford a major new slightly less polar product
  2. waitAfter 2 hours
  3. extractionextracted with three 50 mL portions of ethyl acetate
  4. washThe combined organic layers were washed with four 25 mL portions of brine
  5. dry with materialdried over magnesium sulfate
  6. additiontreated with activated carbon (NORIT A™),
  7. filtrationfiltered through diatomaceous earth
  8. concentrationconcentrated in vacuo
  9. customchromatographed on silica gel

Sources & evidence

ORD record
ord-b40503d63d5d4f839bf1c0c7adc707a5
Source dataset
uspto-grants-2014_06
Patent number
US08741897B2

Reaction notes

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