Methanesulfonic Acid → Dapsone

HRID 1522943Notes

Reaction equation

HRID 1522943 reaction equation
[CH:1]1[C:6]([N+:7]([O-])=O)=[CH:5][CH:4]=[C:3]([S:10]([C:13]2[CH:18]=[CH:17][C:16]([N+:19]([O-])=O)=[CH:15][CH:14]=2)(=[O:12])=[O:11])[CH:2]=1.CS(O)(=O)=O>O.CO.[Pd]>[CH:17]1[C:16]([NH2:19])=[CH:15][CH:14]=[C:13]([S:10]([C:3]2[CH:2]=[CH:1][C:6]([NH2:7])=[CH:5][CH:4]=2)(=[O:12])=[O:11])[CH:18]=1

Participants

6

Reactant 2

HCID 6395Methanesulfonic AcidHCID 70871Benzene, 1,1'-sulfonylbis(4-nitro- (9CI)

Product 1

HCID 2955DapsoneYield 69.5%

Reagents, catalysts & solvents 3

HCID 23938PalladiumCatalystHCID 887MethanolSolventHCID 962WaterSolvent2×

Conditions

Temperature
50 °C

Procedure

In autoclave at room temperature 4,4′-dinitrodiphenylsulfone (0.0649 mol, 20.0 g), 5% palladium on 50% wet carbon (1.4 g), 70% methanesulfonic acid in water (0.130 mol, 17.8 g), water (10 ml) and methanol (70 ml) are loaded. The mixture is left to react under hydrogen pressure (4-5 atm) at a temperature of 55-60° C. for about 8 hours. The mixture is filtered on a Perlite layer washing with methanol (10 ml for 2 times), subsequently with water (80 ml). The solution is concentrated under reduced volume to remove the organic phase. The aqueous phase is extracted with ethyl acetate (50 ml for 3 times) and the organic washings are discarded. Discolouring carbon (1.0 g) is added under vigorous stirring and after 15-20 minutes the mixture is filtered on a Perlite layer. To the aqueous solution heated at about 50° C. a aqueous solution of 30% sodium hydroxide is slowly added to reach a pH higher than 10. After about 30 minutes the mixture is cooled to 0-5° C. and then filtered, washing the solid with water cooled at 0-5° C. (20 ml for three times). After oven-drying at 50° C., 11.2 g of crude Dapsone are obtained that are then crystallized from a mixture of isopropanol (35 ml) and water (25 ml) to obtain 10.2 g of dry Dapsone, having a chemical purity evaluated by HPLC equal to about 98.5%.

Workup

  1. customat room temperature
  2. waitThe mixture is left
  3. customto react under hydrogen pressure (4-5 atm) at a temperature of 55-60° C. for about 8 hours
  4. filtrationThe mixture is filtered on a Perlite layer
  5. washwashing with methanol (10 ml for 2 times), subsequently with water (80 ml)
  6. concentrationThe solution is concentrated under reduced volume
  7. customto remove the organic phase
  8. extractionThe aqueous phase is extracted with ethyl acetate (50 ml for 3 times)
  9. additionDiscolouring carbon (1.0 g) is added
  10. filtrationis filtered on a Perlite layer
  11. additionis slowly added
  12. temperatureAfter about 30 minutes the mixture is cooled to 0-5° C.
  13. filtrationfiltered
  14. washwashing the solid with water
  15. temperaturecooled at 0-5° C. (20 ml for three times)
  16. customAfter oven-drying at 50° C.

Sources & evidence

ORD record
ord-d3062c34ea6d4d128b8715e16175153c
Source dataset
uspto-grants-2015_07
Patent number
US09079831B2

Reaction notes

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