Synonyms: Phosphorothioicacid, O,O-diethyl ester, O-ester with 6-hydroxy-2-phenyl-3(2H)-pyridazinone(7CI,8CI);3(2H)-Pyridazinone, 6-hydroxy-2-phenyl-, O-ester with O,O-diethylphosphorothioate (8CI);American Cyanamid 12,503;CL 12503;ENT 23,968;O,O-Diethyl O-(2,3-dihydro-3-oxo-2-phenyl-6-pyridazinyl) phosphorothioate;O,O-Diethyl phosphorothioate O-ester with6-hydroxy-2-phenyl-3(2H)-pyridazinone;O-(1,6)-Dihydro-6-oxo-1-phenylpyridazin-3-yl) O,O-diethyl phosphorothioate;Ofunack;Oreste;Pyridafenthion;Phosphorothioic acid,O-(1,6-dihydro-6-oxo-1-phenyl-3-pyridazinyl) O,O-diethyl ester;