N-bromobutanimide → 5-(Bromomethyl)benzo[b]thiophene

HRID 1955811Notes

Reaction equation

HRID 1955811 reaction equation
[CH3:1][C:2]1[CH:10]=[CH:9][C:5]2[S:6][CH:7]=[CH:8][C:4]=2[CH:3]=1.C1C(=O)N([Br:18])C(=O)C1>C(Cl)(Cl)(Cl)Cl.CCOCC.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>[Br:18][CH2:1][C:2]1[CH:10]=[CH:9][C:5]2[S:6][CH:7]=[CH:8][C:4]=2[CH:3]=1

Participants

6

Reactant 2

HCID 67184N-bromobutanimideHCID 843465-Methylbenzo(b)thiophene

Product 1

HCID 111604985-(Bromomethyl)benzo[b]thiopheneYield 99.8%

Reagents, catalysts & solvents 3

HCID 7187Benzoyl PeroxideCatalystHCID 3283Diethyl EtherSolventHCID 5943Carbon TetrachlorideSolvent

Procedure

A mixture of 5-methylbenzo[b]thiophene (3.8 g, 25.6 mmol), NBS (4.7 g, 27 mmol), and benzoyl peroxide (310 mg, 1.3 mmol) were refluxed one hour in CCl4 (100 mL) while being irradiated with a sunlamp. Upon completion, the reaction was cooled, diluted with Et2O, filtered and concentrated to yield 5.8 g of 5-bromomethylbenzo[b]thiophene. The crude 5-bromomethylbenzo[b]thiophene was refluxed for 36 hours in 1:1 dioxane/2N aq. NaOH (128 mL). After cooling, extraction with EtOAc and concentration of the extracts, the residue was chromatographed on silica gel eluting 2.6 g of 5-hydroxymethylbenzo[b]thiophene with 35% EtOAc/hexane. The title compound (1.96 g) was obtained after filtration and concentration of the reaction product produced by refluxing 5-hydroxymethylbenzo[b]thiophene (2.08 g, 12.7 mmol) and 50% MnO2 /C (17.6 g, 101 mmol) for five hours in toluene while H2O was continually removed using a Dean-Stark trap.

Workup

  1. customwhile being irradiated with a sunlamp
  2. temperatureUpon completion, the reaction was cooled
  3. filtrationfiltered
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-b6bf6ff552bc4de9a34d05cab3522f04
Source dataset
uspto-grants-1998_07
Patent number
US05776983

Reaction notes

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