Studies on Mesoionic Compounds. I. Synthesis of 3-Dialkylaminosydnonimines

3-Dialkylaminosydnonimine salts (IV) were synthesized starting from 1, 1-dialkyl-hydrazines (I) via II and III. IV exhibits a remarkable stability towards acids and could be obtained as crystals. Chemical and physicochemical properties of IV were similar to those of known sydnonimine salts. It should be mentioned that intermediary nitroso compounds (III) were rather unstable and spontaneously gave rise to unsaturated nitriles (III').