Reaction of 1-chloromethyl-4,5-dichloropyridazin-6-one with some nucleophil
es such as sodium methoxide, sodium azide, 2-mercaptopyrimidine and phenol
gave 2, 3, 4, 7, 8 and 10. 5-Chloro-4-phenoxypyridazin-6-one (10) was also
synthesized from 8 through 9.