Dichloro-Substituted 1,2-Diazabuta-1,3-dienes as Highly Reactive Electrophiles in the Reaction with Amines and Diamines: Efficient Synthesis of α-Hydrazo Amidinium Salts

The reaction of 4,4-dichloro-1,2-diazabuta-1,3-dienes with various amines and diamines was studied. We found that in this reaction, the starting diazabutadienes behave as highly reactive electrophiles to open up a straightforward route to the corresponding amidinium salts with a hydrazone functionality in the adjacent position. The reaction was found to be very general; as a rule, all the products could be prepared in almost quantitative yields. We also demonstrated that the prepared amidinium salts could be used as versatile building blocks for the synthesis of polyfunctional molecules. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim