Conspicuously absent from the chemical literature are sulfonamides in the benzimidazole, benzothiazole and benzotriazole series. One reason for this may have been the lack of the corresponding sulfonic acids until the last decade.','Moreover, although the sulfonic acids are now available, they cannot be converted into the necessary sulfonyl chlorides by the usual methods, nor can the chlorides be prepared by the use of chlorosulfonic acid. A ...
