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1,3‐dipolar cycloadditions of 2‐diazobutane, diazophenylmethane and 1‐diazo‐1‐phenylethane to azolopyridazines. The isolation of some primary and rearranged cycloadducts and their transformations into substituted pyrazolo[4,3‐ d ]azolopyridazines
Author(s) -
Huč Branko,
Furlan Borut,
Stanovnik Branko,
Tišsler Miha
Publication year - 1990
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.5570270754
Subject(s) - chemistry , diazo , cycloaddition , primary (astronomy) , medicinal chemistry , stereochemistry , 1,3 dipolar cycloaddition , organic chemistry , catalysis , physics , astronomy
The 1,3‐dipolar cycloaddition of 2‐diazobutane ( 2 ) to azolopyridazines 1 gave 9‐ethyl‐9‐methyl‐7,8‐dihydropyrazolo[4,3‐ d ]‐ 4 and 9‐ethyl‐9‐methyl‐9 H ‐pyrazolo[4,3‐ d ]azolopyridazines 5 . With diazophenylmethane ( 6 ) 7‐benzyl‐8‐phenyl‐7 H ‐ 12 and 8‐benzyl‐9‐phenyl‐8 H ‐pyrazolo[4,3‐ d ]azolopyridazines 13 were obtained, while with 1‐diazo‐1‐phenylethane ( 14 ) the primary cycloadducts 15 , and rearranged cycloadducts 16 and 17 were isolated in some instances and further transformed into 9‐methyl‐9‐phenyl‐9 H ‐pyrazolo[4,3‐ d ]azolopyridazines 18 .