Inorganic chemistry, thesulfonamidefunctional group (also spelledsulphonamide) is anorganosulfur group with thestructureR−S(=O)2−NR2. It consists of asulfonyl group (O=S=O) connected to anamine group (−NH2). Relatively speaking this group isunreactive. Because of the rigidity of the functional group, sulfonamides are typicallycrystalline; for this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by itsmelting point. Many important drugs contain the sulfonamide group.[1]
Asulfonamide (compound) is achemical compound that contains this group. The general formula isR−SO2NR'R" orR−S(=O)2−NR'R", where each R is some organic group; for example, "methanesulfonamide" (where R =methane, R' = R" =hydrogen) isCH3SO2NH2. Any sulfonamide can be considered as derived from asulfonic acid by replacing ahydroxyl group (−OH) with an amine group.
Inmedicine, the term "sulfonamide" is sometimes used as a synonym forsulfa drug, a derivative or variation of sulfanilamide. The first sulfonamide was discovered in Germany in 1932.[2]
Sulfonamides can be prepared in the laboratory in many ways. The classic approach entails the reaction ofsulfonyl chlorides with anamine.[citation needed]
A base such aspyridine is typically added to absorb the HCl that is generated. Illustrative is the synthesis of sulfonylmethylamide.[3]The reaction of primary and secondary amines withbenzenesulfonyl chloride is the basis of theHinsberg reaction, a method for detecting primary and secondary amines.
Sulfonamides undergo a variety of acid-base reactions. The N-H bond can be deprotonated. The alkylsulfonamides can be deprotonated at carbon. Arylsulfonamides undergoortho-lithiation.[4]
Sultams are cyclic sulfonamides. Bioactive sultams include the antiinflammatoryampiroxicam and the anticonvulsantsulthiame. Sultams are prepared analogously to other sulfonamides, allowing for the fact that sulfonic acids are deprotonated by amines. They are often prepared by one-pot oxidation of disulfides or thiols linked to amines.[5] An alternative synthesis of sultams involves initial preparation of a linear sulfonamide, followed by intramolecular C-C bond formation (i.e. cyclization), a strategy that was used in the synthesis of a sultam-based deep-blue emitter fororganic electronics.[6]
Thedisulfonimides are of the typeR−S(=O)2−N(H)−S(=O)2−R' with two sulfonyl groups flanking an amine.[7] As withsulfinamides, this class of compounds is used as catalysts inenantioselective synthesis.[7][8][9]
Bis(trifluoromethanesulfonyl)aniline is a source of thetriflyl (CF3SO+2) group.
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