Dapsone

Anti-Infective Agents, Antimalarials, Folic Acid Antagonists, Leprostatic Agents.

Used in leprosy treatment and veterinary medicine.

Hardening agent in the curing of epoxy resins.

Dapsone is approved for use in dermatitis herpetiformis and leprosy. It is particularly useful in the treatment of linear immunoglobulin (IgA) dermatosis, bullous systemic lupus erythematosus, erythema elevatum diutinum, and subcorneal pustular dermatosis.

Industrial uses: Adhesion/cohesion promoter, Hardener, Intermediate.

Use classes: Pharmaceuticals.

Dapsone is a synthetic derivative of diamino-sulfone with anti-inflammatory and anti-bacterial properties. As a structural analog of p-aminobenzoic acid (PABA), dapsone inhibits dihydropteroate synthase (DHPS), an enzyme important in folate synthesis, resulting in a depletion of the folate pool and a reduction in the amount of thymidylate available for DNA synthesis. Although the exact mechanism through which dapsone exerts its anti-inflammatory activity has yet to be fully elucidated, this agent interferes with the activation and oxidative damage of myeloperoxidase in neutrophils and inhibits the integrin-mediated adherence and chemotaxis of neutrophils. Dapsone's anti-inflammatory activities may contribute to the effects seen upon topical administration.

Reaction (of 4-chloronitrobenzene) with sodium sulfide can be controlled to give 4-amino-4'-nitrodiphenyl sulfide, which after N-acetylation and oxidation with hydrogen peroxide forms (4-nitro-4'-acetylaminodiphenyl sulfone): subsequent reduction and hydrolysis yields 4,4'-diaminodiphenyl sulfone (dapsone) ...

Preparation: French patent 829926 (1938 to I. G. Farbenind)

Benzene is condensed with sulfuric acid to yield phenyl sulfone which is then nitrated by standard procedures to yield the 4,4'-dinitro derivative. Reduction with tin and HCl (hydrochloric acid) or with various other appropriate reductants yields dapsone.