Hydrochloric Acid → HCID 23312091, compound

HRID 745794Notes

Reaction equation

HRID 745794 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]([OH:17])[C:5]([OH:16])=[CH:6][C:7]=1[S:8]([C:11]1[S:12][CH:13]=[CH:14][CH:15]=1)(=[O:10])=[O:9].C([O:20][C:21](=[O:25])[CH:22](Cl)Cl)C.C(=O)([O-])[O-].[K+].[K+].Cl>COCCOC.O>[CH3:1][C:2]1[C:7]([S:8]([C:11]2[S:12][CH:13]=[CH:14][CH:15]=2)(=[O:10])=[O:9])=[CH:6][C:5]2[O:16][CH:22]([C:21]([OH:25])=[O:20])[O:17][C:4]=2[CH:3]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 10808Ethyl dichloroacetateHCID 11430Potassium CarbonateHCID 23312102HCID 23312102, compound

Product 1

HCID 23312091HCID 23312091, compound

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 80711,2-DimethoxyethaneSolvent

Procedure

In a manner analogous to that described in Example 4, 30.0 g (111 mmol) of 4-methyl-5-(2-thienylsulphonyl)-1,2-benzenediol, 17.4 g (111 mmol) of dichloroacetic acid ethyl ester and 76.7 g (555 mmol) of potassium carbonate in 300 ml of 1,2-dimethoxyethane are boiled under reflux. After 18 hours, the reaction mixture is poured into water, stirred for one hour at room temperature and then adjusted to pH 1-2 by means of hydrochloric acid. Some of the 1,2-dimethoxyethane is distilled off in vacuo and the mixture remaining is extracted with ethyl acetate. The combined organic phases are washed with water and saturated sodium chloride solution, dried over sodium sulphate and concentrated by evaporation in a rotary evaporator. The resulting dark-red oil is chromatographed over silica gel. As eluant, a mixture of chloroform/methanol/concentrated ammonia in a ratio of 40:10:1 is used until elution of the starting diol, then an analogous mixture in a ratio of 12:5:1 is used. The uniform fractions are combined and concentrated almost completely by evaporation. Ice/water is added to the residue and the pH is adjusted to 1-2 with concentrated hydrochloric acid. The acidic solution is extracted with ethyl acetate. The combined organic phases are washed, dried and concentrated by evaporation. The residue is boiled in diisopropyl ether and the black sludge formed is removed by decanting. The clear solution is concentrated to a large extent and the substance which has crystallised out is filtered off with suction. The crystals are recrystallised from 1,2-dichloroethane, yielding 5-methyl-6-(2-thienylsulphonyl)-1,3-benzodioxole-2-carboxylic acid in the form of white crystals having a melting point of 162.5°-164.5°.

Workup

  1. temperatureunder reflux
  2. distillationSome of the 1,2-dimethoxyethane is distilled off in vacuo
  3. extractionthe mixture remaining is extracted with ethyl acetate
  4. washThe combined organic phases are washed with water and saturated sodium chloride solution
  5. dry with materialdried over sodium sulphate
  6. concentrationconcentrated by evaporation in a rotary evaporator
  7. customThe resulting dark-red oil is chromatographed over silica gel
  8. additionAs eluant, a mixture of chloroform/methanol/concentrated ammonia in a ratio of 40:10:1
  9. washis used until elution of the starting diol
  10. concentrationconcentrated almost completely by evaporation
  11. additionIce/water is added to the residue
  12. extractionThe acidic solution is extracted with ethyl acetate
  13. washThe combined organic phases are washed
  14. customdried
  15. concentrationconcentrated by evaporation
  16. customthe black sludge formed
  17. customis removed
  18. customby decanting
  19. concentrationThe clear solution is concentrated to a large extent
  20. customthe substance which has crystallised out
  21. filtrationis filtered off with suction
  22. customThe crystals are recrystallised from 1,2-dichloroethane

Sources & evidence

ORD record
ord-17fdf7b9997a447788e98c12cfc7cb84
Source dataset
uspto-grants-1986_07
Patent number
US04600709

Reaction notes

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