Sulfonylcarbamimidic azides from sulfonyl chlorides and 5‐aminotetrazole

Treatment of o‐nitrobenzenesulfonyl chloride (3) with 5‐aminotetrazole (5‐AT) gave [(2‐nitrophenyl)‐sulfonyl]carbamimidic azide (6), a ring‐opened isomer of the expected N‐(1H‐tetrazol‐5‐yl)‐2‐nitrobenzenesulfonamide (4). Sulfonylcarbamimidic azide 6 was converted to 2‐amino‐N‐(aminoiminomethyl)benzene‐sulfonamide (7) with ethanolic stannous chloride, and to 3‐amino‐1,2,4‐thiadiazine 1,1‐dioxide (8) with sodium dithionite. Methanesulfonyl chloride (9) and 5‐AT gave 2‐(methylsulfonyl)carbamimidic azide (10), which isomerized to 5‐[(methylsulfonyl)amino]‐1H‐tetrazole (11) in warm ethanol. Attempted cycloaddition of 2‐(phenylsulfonyl)carbamimidic azide (13) and ethyl vinyl ether led only to alkylated tetrazole products. In addition, other tetrazole‐alkylating reactions are described. Isomers produced from these alkylations were differentiated with 13C nmr spectroscopy.