Thionyl Chloride → 5-Chlorocarbonylphthalide

HRID 2180317Notes

Reaction equation

HRID 2180317 reaction equation
S(Cl)([Cl:3])=O.[C:5]([C:8]1[CH:9]=[C:10]2[C:15](=[CH:16][CH:17]=1)[C:13](=[O:14])[O:12][CH2:11]2)(O)=[O:6]>CN(C)C=O>[Cl:3][C:5]([C:8]1[CH:9]=[C:10]2[C:15](=[CH:16][CH:17]=1)[C:13](=[O:14])[O:12][CH2:11]2)=[O:6]

Participants

4

Reactant 2

HCID 24386Thionyl ChlorideHCID 785171,3-Dihydro-1-oxoisobenzofuran-5-carboxylic acid

Product 1

HCID 98155555-ChlorocarbonylphthalideYield 86%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
80 °C

Procedure

To a mixture of 1800 ml of thionyl chloride and 8.1 ml of N,N-dimethylformamide, 750 g (4.21 moles) of 5-carboxyphthalide are added under stirring. The mixture is heated slowly to reach an inner temperature of 60° C. in one hour, then it is kept at this temperature for another hour and finally it is brought to the reflux. After refluxing for 6 hours, about 600 ml of thionyl chloride are distilled off at a temperature of 80÷85° C., by replacing them by addition of toluene. Distillation is continued for a total of 2800 ml with concurrent replacement of the solvent by addition of 3800 ml of toluene. The mixture is slowly cooled and, at 80° C., the crystallization of the product begins. Cool to 10÷15° C. by continuing stirring for 15 hours. The hygroscopic product is filtered, washing with a total of 1500 ml of toluene, then it is dried under vacuum at 55° C. to give 710 g (86%) of 5-chlorocarbonylphthalide with a purity of 99% (HPLC).

Workup

  1. additionare added
  2. temperatureThe mixture is heated slowly
  3. customan inner temperature of 60° C.
  4. customin one hour
  5. waitit is kept at this temperature for another hour
  6. temperatureAfter refluxing for 6 hours
  7. distillationabout 600 ml of thionyl chloride are distilled off at a temperature of 80÷85° C.
  8. additionby addition of toluene
  9. distillationDistillation
  10. additionis continued for a total of 2800 ml with concurrent replacement of the solvent by addition of 3800 ml of toluene
  11. customthe crystallization of the product
  12. temperatureCool to 10÷15° C.
  13. stirringby continuing stirring for 15 hours
  14. filtrationThe hygroscopic product is filtered
  15. washwashing with a total of 1500 ml of toluene
  16. customit is dried under vacuum at 55° C.

Sources & evidence

ORD record
ord-610e19455c554551be13d7325eb6ce24
Source dataset
uspto-grants-2005_05
Patent number
US06888010B2

Reaction notes

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