Reaction of Alkylsulfanylchloroacetylenes with 1,1-Dimethylhydrazine

Alkylsulfanylchloroacetylenes react with 1,1-dimethylhydrazine in diethyl ether at 20–22°C to give, depending on the reactant ratio, 3,6-bis(alkylsulfanylmethyl)-1,1,4,4-tetramethyl-1,4-dihydro-1,2,4,5- tetrazine-1,4-diium dichlorides (yield 67–80%) or 1-[2-(alkylsulfanyl)-1-(2,2-dimethylhydrazono)ethyl]-1,1-dimethylhydrazinium chlorides. The latter readily undergo dequaternization to the corresponding 2-alkylsulfanyl-N1,N2,N4-trimethylethanohydrazide hydrazones (yield up to 53%).