90330-88-4

Upstream product

• 59026-46-9 1,5-dibenzyl-3-phenyl-1H-pyrazolo<3,4-d>pyridazin-4(5H)-one 
• 90330-80-6 2-phenyl-4H-pyridazino<4,5-e><1,3,4>thiadiazin-8(7H)-one 
• 90330-76-0 4-acetyl-2-phenyl-4H-pyridazino<4,5-e><1,3,4>thiadiazin-8(7H)-one 
• 91063-66-0 5-benzylidene-hydrazino-4-chloro-3(2H)-pyridazinone 
• 59026-52-7 2-Benzyl-5-{N-benzyl-N'-[1-phenyl-meth-(E)-ylidene]-hydrazino}-4-chloro-2H-pyridazin-3-one 
• 90330-85-1 5-<(α-bromobenzylidene)hydrazino>-4-chloro-3(2H)-pyridazinone 

Downstream Products

• 94773-59-8 3-phenyl-1H-pyrazolo<3,4-d>pyridazine-4(5H)-thione 
• 94773-60-1 4-Methylsulfanyl-3-phenyl-1H-pyrazolo[3,4-d]pyridazine 

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 PYRAZOLOPYRIDAZINES - THIONATION FOLLOWED BY ALKYLATION OF PYRAZOLOPYRIDAZIN-4(5H)-ONE

Alkylation of the pyrazolopyridazine-4(5H)-thiones are described.Employment of an equivalent of alkylating agent afforded only S-alkylated products, while S,N-dialkyl compounds were formed when an excess of alkylating agent was used.An unequivocal