Thionyl Chloride → 7-tert-butyl-3-chloro-5-methyl-3H-benzofuran-2-one

HRID 278517Notes

Reaction equation

HRID 278517 reaction equation
[C:1]([C:5]1[C:13]2[O:12][C:11](=[O:14])[CH:10](O)[C:9]=2[CH:8]=[C:7]([CH3:16])[CH:6]=1)([CH3:4])([CH3:3])[CH3:2].S(Cl)([Cl:19])=O>CN(C)C=O>[C:1]([C:5]1[C:13]2[O:12][C:11](=[O:14])[CH:10]([Cl:19])[C:9]=2[CH:8]=[C:7]([CH3:16])[CH:6]=1)([CH3:4])([CH3:3])[CH3:2]

Participants

4

Reactant 2

HCID 24386Thionyl ChlorideHCID 186202687-tert-butyl-3-hydroxy-5-methyl-3H-benzofuran-2-one2×

Product 1

HCID 226285707-tert-butyl-3-chloro-5-methyl-3H-benzofuran-2-oneYield 13%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideCatalyst

Procedure

To a suspension of 2.2 g (10.0 mmol) of 7-tert-butyl-3-hydroxy-5-methyl-3H-benzofuran-2-one (compound (202), Example la, Table 2) in 2.4 ml (55.0 mmol) of thionyl chloride is added one drop of dimethyl formamide and the mixture is stirred for 2 hours at room temperature. Excess thionyl chloride is afterwards distilled off on a vacuum rotary evaporator. Chromatography of the residue on silica gel with the solvent system dichloromethane/hexane=1:1 and crystallisation of the pure fractions from methanol yields 0.30 g (13%) of 7-tert-butyl-3-chloro-5-methyl-3H-benzofuran-2-one, m.p. 81-86° C. (compound (208), Table 2).

Workup

  1. distillationExcess thionyl chloride is afterwards distilled off on a vacuum rotary evaporator
  2. customChromatography of the residue on silica gel with the solvent system dichloromethane/hexane=1:1 and crystallisation of the pure fractions from methanol

Sources & evidence

ORD record
ord-774352e17ef24d1592c9480d08137777
Source dataset
uspto-grants-2002_03
Patent number
US06359148B1

Reaction notes

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