Thiadiazoles reactions

The ring nitrogens react with electrophiles to afford either 1,3,4-thiadiazolium salts or l,3,4-thiadiazol-2(37/)-ones depending on the tautomerisability of the substituents at the C-2 or C-5 positions. While N-alkylation is the most common electrophilic reaction of 1,3,4-thiadiazoles, reactions with acyl and cyanogen halides as well as Mannich salts have also been reported. 

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