Sulfonyl amides or sulfonamides are organosulfur compounds that consists of a sulfonyl group (O=S=O) connected to an amine group. They can be considered as amides of sulfonic acid. They can be prepared by reaction of sulfonyl chlorides with an amine. Sultams are cyclic sulfonamides. Sulfonamide drugs were the first broadly effective antibacterials. Moreover, some sulfonamide drugs have antifungal and antimalarial functions. They are also used as a diuretics and COX-2 inhibitors.