Synthesis of heterocyclic sulfonamides
1991
Cuomo, J. | Gee, S.K. | Hartzell, S.L.
Once it was realized that heteroaromatic sulfonamides could be prepared and converted to sulfonylureas, and that these compounds possessed many of the desirable herbicidal qualities of the benzene sulfonylureas, a large synthetic effort was started to prepare more examples. Using thiophene and pyrazole as representative examples, we have been able to synthesize all of the positional isomers of the mono- and di-substituted sulfonamides. This paper will outline the major synthetic pathways that we have discovered, emphasizing directed metallation processes and nucleophilic substitution reactions, leading to the preparation of these heterocyclic sulfonamides. Many of the methods developed for thiophene and pyrazole sulfonamide synthesis have been extended to the synthesis of pyridine and other heteroaromatic sulfonamides.
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