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3‐Methylpyrazolo [1,2‐ a ] pyridazin‐1‐one. Selenium derivatives of 5,8‐dihydropyrazolo[1,2‐ a ]pyridazine
Author(s) -
Farnum Donald G.,
Au Andrew T.,
Rasheed Khalid
Publication year - 1971
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570080105
Subject(s) - chemistry , pyridazine , pyrazolones , dehydrogenation , selenium , medicinal chemistry , organic chemistry , catalysis
The dehydrogenation of the known 3‐methyl‐5,8‐dihydropyrazolo[1,2‐ a ]pyridazin‐1‐one (2) to the ten π electron heteroaromatic 3‐methylpyrazolo[1,2‐ a ]pyridazin‐1‐one ( 3 ) is reported. Conversions of the pyrazolone 2 to the pyrazoloselenone 6 via the chloropyrazolium chloride 7 , and of pyrazolones 2 and 3 and pyrazoloselenone 6 into the corresponding O or Se ethyl pyrazolium fluoroborates 5, 4 , and 8 by triethyloxonium fluoroborate are also described.