78868-96-9

Upstream product

• 59026-55-0 5-Benzylidenehydrazino-4-chloro-2-methyl-3(2H)-pyridazinones 
• 90330-82-8 2-methyl-5-<(α-bromobenzylidene)hydrazino>-4-chloro-3(2H)-pyridazinone 
• 10387-40-3 potassium thioacetate 

Downstream Products

• 90330-81-7 4,7-dimethyl-2-phenyl-4H-pyridazino<4,5-e><1,3,4>thiadiazin-8(7H)-one 
• 59026-43-6 1,5-dimethyl-3-phenyl-1H-pyrazolo<3,4-d>pyridazin-4(5H)-one 
• 90330-77-1 7-methyl-2-phenyl-4H-pyridazino<4,5-e><1,3,4>thiadiazin-8(7H)-one 

Relevant academic research and scientific papers

SYNTHESIS OF PYRAZOLOPYRIDAZINE DERIVATIVES- TWO COMPARABLE APPROACHES, RING CONTRACTION THROUGH EXTRUSION OF SULPHUR AND PHOTOCHEMICAL CYCLISATION

Ring contraction of 7-substituted 2-phenyl-4H-pyridazinothiadiazin-8(7H)-ones (5a-d) to 5-substituted 3-phenyl-1H-pyrazolopyridazin-4(5H)-ones (7a-d), through base-induced extrusion of sulphur, is described.Similar reactions proceed, not only on the 4-acetyl derivatives (4a-d) in basic media, but on 5a and the 4-methyl derivative (6a) thermally.Probable mechanism of these reactions are discussed.A comparable approach to the ring contraction, photochemical cyclisation of 2-substituted 5-(1-alkyl-2-benzylidenehydrazino)-4-chloro-3(2H)-pyridazinones (9a-e) to the corresponding 1-alkylpyrazolo-pyridazinone derivatives (8a-e) is also performed.

Synthesis of Pyridazinothiadazines and the Ring Contraction to Pyrazolopyridazines through Extrusion of Sulfur

Cyclization of 2-substituted 5-4-chloro-3(2H)-pyridazinones (2) with potassium thioacetate, followed by deacetylation, provided new ring system derivatives, 7-substituted 2-phenyl-4H-pyridazinothiadiazin-8(7H)