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ChemicalBook CAS DataBase List 4,4'-Diaminodiphenylsulfone
80-08-0

4,4'-Diaminodiphenylsulfone synthesis

15synthesis methods
Dapsone, 4,4-diaminodiphenylsulfone (34.2.3), is synthesized from either 4-chloronitrobenzene or from the sodium salt of 4-acetamidobenzenesulfonic acid. Reacting 4-chloronitrobenzene with sodium sulfide gives 4,4-dinitrodiphenylthioester (34.2.1), and oxidation of the sulfur atom in this compound using potassium dichromate in sulfuric acid gives 4,4-dinitrodiphenylsulfone (34.2.2). Reduction of the nitro group in the resulting compound using tin dichloride in hydrochloric acid makes the desired dapsone.
It has also been suggested to reduce the nitro group to an amino group, protect it with an acetyl protection, oxidize the sulfur atom to a sulfone using potassium dichromate, and then remove the protective acetyl group by hydrolysis.

Another way of the synthesis of dapsone begins with 4-acetamidobenzenesulfonic acid, which is reacted with 4-chloronitrobenzene at high temperatures to give 4-acetamido-4- nitrodiphenylsulfone (34.2.4). Reducing the nitro group in this compound with tin dichloride in hydrochloric acid along with the simultaneous hydrolysis of the acetyl group under the reaction conditions gives the desired dapsone.
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Yield:80-08-0 91.9%

Reaction Conditions:

with ammonium chloride in ethanol; for 5 h;Reflux;

Steps:

2

50.0 ml of ethanol was taken in a 250 ml three-necked flask, And then slowly adding 4,4'-dichlorodiphenylsulfone 10.0 g (40.27 mmol), 4.30 g (80.54 mmol) of ammonium chloride solid, while stirring while adding 50.0 ml of ethanol, heating reflux reaction 5h, TLC point The reaction was completed, 30ml of distilled water slowly quenched the reaction, stirring cooling, to be a large number of solid precipitation, filtration, with a small amount of ethanol washing filter cake three times, at 40 blast drying, to obtain white crystalline powder 7.9g, Yield: 91.9%.

References:

CN106518735,2017,A Location in patent:Paragraph 0011

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