22439-37-8 BRN 0671622 O,O-Diethyl phosphorothioate S-ester with 6-chloro-2-(mercaptomethyl)-3(2H)-pyridazinone Phosphorothioic acid, O,O-diethyl ester, S-ester with 6-chloro-2-(mercaptomethyl)-3(2H)-pyridazinone