Reaktion von 2‐Thiophenaminen mit Hydrazin

Reaction of 2‐Thiophenamines with Hydrazine Depending on their substituents 2‐thiophenamines react with hydrazine hydrate on different ways: Hydrazinolysis of the ester 1 yields the 2‐amino‐3‐thiophenecarbohydrazide 2. 4‐Phenyl‐2‐thiophenamine (4) is converted into the 2(5H)‐thiophenone hydrazone 5 by exchange of the amino group. The thiophenamines 7, 9, 12 undergo ring transformation to yield pyridazine derivatives, the N,N′‐bis(dihydro‐3‐pyridazinyl)hydrazine 8, the 3‐pyridazinylhydrazine 10, and the pyrazolo[3,4‐c]pyridazine 13. From 10 the 1,2,4‐triazolo[4,3‐b]pyridazine 11 is obtained.