N-bromobutanimide → 6,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

HRID 1606326Notes

Reaction equation

HRID 1606326 reaction equation
[C:1]([C:5]1[CH:6]=[C:7]([C:21]([CH3:24])([CH3:23])[CH3:22])[C:8]2[O:13][CH:12]([C:14]([O:16][CH2:17][CH3:18])=[O:15])[CH2:11][C:10](=[O:19])[C:9]=2[CH:20]=1)([CH3:4])([CH3:3])[CH3:2].BrN1C(=O)CCC1=O>C(Cl)(Cl)(Cl)Cl>[C:1]([C:5]1[CH:6]=[C:7]([C:21]([CH3:22])([CH3:24])[CH3:23])[C:8]2[O:13][C:12]([C:14]([O:16][CH2:17][CH3:18])=[O:15])=[CH:11][C:10](=[O:19])[C:9]=2[CH:20]=1)([CH3:4])([CH3:3])[CH3:2]

Participants

4

Reactant 2

HCID 67184N-bromobutanimideHCID 867332766,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

Product 1

HCID 538439426,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

A mixture of 3.32 parts of 6,8-di-t-butyl-2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester and 1.84 parts of N-bromosuccinimide was refluxed in 150 parts of carbon tetrachloride for six hours. The solution was cooled and then washed with water. The carbon tetrachloride extract was dried and the solvent was removed by evaporation. The resulting brown residue was crystallised from light petroleum (b.p. 40°-60°C) to give 1.69 parts of 6,8-di-t-butyl-4-oxo-4H-1-benzopyran-2-carboxylic acid, ethyl ester, m.p. 130°-131.5°C. The ester was hydrolysed to the sodium salt using the process of Example 5.

Workup

  1. temperatureThe solution was cooled
  2. washwashed with water
  3. extractionThe carbon tetrachloride extract
  4. customwas dried
  5. customthe solvent was removed by evaporation
  6. customThe resulting brown residue was crystallised from light petroleum (b.p. 40°-60°C)

Sources & evidence

ORD record
ord-9fdadde0acae4980a6283e7c9c72a9bb
Source dataset
uspto-grants-1976_04
Patent number
US03952104

Reaction notes

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