Abstract
N-oxidation of 5-amino-3, 4-dichloropyridazine and 4-amino-3, 5-dichloropyridazine gave their 1-oxides. The amino groups on 3-, 4-, 5-, and 6-positions of pyridazine 1-oxide were substituted with chlorine or bromine by diazotization, but yield of 3-bromopyridazine 1-oxide was poor. 5-Amino-3, 4-dichloropyridazine 1-oxide is usable as the starting material for the preparation of 5-substituted pyridazine 1-oxides.
