Sulfonamide (chemistry)

In chemistry, the sulfonamide functional group is -S(=O)₂-NH₂, a sulfone group connected to an amine group.

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A sulfonamide (compound) is a compound that contains this group. The general formula is RSO₂NH₂, where R is some organic group. For example, "methanesulfonamide" is CH₃SO₂NH₂. Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group with an amine group.

In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivative or variation of sulfanilamide.

Organic synthesis

Sulfonamides can be prepared in the laboratory in many ways:

by reaction of sulfonyl chlorides with amines for example in the synthesis of sulfonylmethylamide ^[1]. A readily available sulfonyl chloride source is tosyl chloride ^[2]
In one study symmetric sulfonamides are prepared directly from amines and sulfur dioxide gas ^[3]:

In this example the reactant is aniline and the catalysts are triethylamine and iodine. Sulfur dioxide is believed to be activated through a series of intermediates: Et₃N-I⁺-I^-, Et₃N-I⁺-I₃^- and Et₃N⁺-SO₂^-.

References

^ Organic Syntheses, Coll. Vol. 4, p.943 (1963); Vol. 34, p.96 (1954). Online Article
^ Organic Syntheses, Coll. Vol. 5, p.39 (1973); Vol. 48, p.8 (1968). Online Article
^ Sulfamides and sulfamide polymers directly from sulfur dioxide Alexander V. Leontiev, H. V. Rasika Dias and Dmitry M. Rudkevich Chem. Commun., 2006, 2887 - 2889, doi:10.1039/b605063h