HCID 69696755, compound → 6,7-Dichloro-4-oxo-4H-1-benzopyran-2-carboxylic acid

HRID 897234Notes

Reaction equation

HRID 897234 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([CH:14]=[CH:15][C:16]=1[Cl:17])[O:5][C:6](=[CH:10][C:11]([OH:13])=O)[C:7]([OH:9])=[O:8]>CS(O)(=O)=O.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O>[Cl:17][C:16]1[CH:15]=[C:14]2[C:4](=[CH:3][C:2]=1[Cl:1])[O:5][C:6]([C:7]([OH:9])=[O:8])=[CH:10][C:11]2=[O:13]

Participants

3

Reactant 1

HCID 69696755HCID 69696755, compound

Product 1

HCID 223480726,7-Dichloro-4-oxo-4H-1-benzopyran-2-carboxylic acidYield 29.5%

Reagents, catalysts & solvents 1

HCID 86584057Phosphorus Pentoxide-Methanesulfonic AcidSolvent

Conditions

Temperature
70 °C

Procedure

2-(3,4-Dichloro-phenoxy)-but-2-enedioic acid (17.98 g, 64.9 mmol) was combined with Eaton's Reagent (140 ml). The mixture was heated at 70° C overnight. After 14 h, the mixture was cooled to ambient temperature and added to ice (600 g). The resulting white precipitate was collected by filtration, washed with copious water, and air-dried. The white solid (16.8 g) was dissolved in hot DMSO and cooled slowly to ambient temperature. The supernatant was recovered and concentrated, and the process was repeated to provide the desired compound (4.96 g, 29%) as a white solid. The crystalline material proved to be the undesired 5,6-dichloro isomer. MS (APCI) m/z 259 [M+H]+; 1H NMR (300 MHz, DMSO-D6) δ ppm 6.96 (s, 1H) 8.16 (s, 1H) 8.26 (s, 1H).

Workup

  1. temperaturethe mixture was cooled to ambient temperature
  2. filtrationThe resulting white precipitate was collected by filtration
  3. washwashed with copious water
  4. customair-dried
  5. dissolutionThe white solid (16.8 g) was dissolved in hot DMSO
  6. temperaturecooled slowly to ambient temperature
  7. customThe supernatant was recovered
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-136f091935734200a44a48376ed6bfde
Source dataset
uspto-grants-2005_07
Patent number
US06921821B2

Reaction notes

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