6-Chloro-3-hydroxypyridazine
6-Chloro-4-ethylpyridazin-3(2H)-one
6-Chloro-4-methylpyridazin-3(2H)-one
6-Chloro-5-methylpyridazin-3(2H)-one
5,6-Dichloropyridazin-3(2H)-one
