79050-49-0Relevant articles and documents
Process for Preparing Malathion for Pharmaceutical Use
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Page/Page column 12, (2008/06/13)
The present invention provides a process for preparing a highly pure form of malathion having a reduced level of toxic impurities. In addition, the malathion prepared by the process of this invention is storage stable. The level of toxic impurities in the malathion, e.g., isomalathion, O,O,S-trimethyl phosphorodithioate (MeOOSPS), O,O,S-trimethyl phosphorothioate (MeOOSPO), O,S,S-trimethyl phosphorodithioate (MeOSSPO), malaoxon, isomalathion, diethyl fumarate, methyl malathion, dimethyl malathion, O,O-methyl,ethyl-S-(1,2-dicarboethoxy)ethyl-phosphorodithioate are lower than that of any other commercial preparation of malathion that may be used for pharmaceutical purposes.
S-methylation of O,O-dialkyl phosphorodithioic acids: O,O,S-trimethyl phosphorodithioate and phosphorothiolate as metabolites of dimethoate in mice
Mahajna, Mahmoud,Quistad, Gary B.,Casida, John E.
, p. 1202 - 1206 (2007/10/03)
O,O,S-Trimethyl phosphorodithioate and phosphorothiolate [(MeO)2P(S)SMe and (MeO)2P-(O)SMe, respectively] are known from earlier studies to be impurities, delayed toxicants, and detoxication inhibitors in several major O,O-dimethyl phosphorodithioate insecticides. Our recent studies show extensive S-methylation of mono- and dithiocarbamic acids in mice, suggesting the possibility that phosphorodithioic acids such as (MeO)2P(S)SH might also undergo S-methylation. This possibility was examined in ip-treated mice with emphasis on the metabolites of dimethoate [(MeO)2P(S)SCH2C(O)NHMe], one of the most important organophosphorus insecticides. The urinary metabolites of dimethoate, which contains no P-SMe substituent, were found to include four compounds with P-SMe moieties identified by 31P NMR spectroscopy as MeO(HS)P(O)SMe, MeO(HO)P(O)SMe, (MeO)2P(S)SMe, and (MeO)2P-(O)SMe; the latter two compounds are also established by GC-MS as dimethoate metabolites in mouse urine, liver, kidney, and lung. Several approaches verified unequivocally that the previously unknown P-SMe metabolites in urine and tissues are due to in vivo S-methylation rather than to impurities. Studies with other O,O-dimethyl and O,O-diethyl phosphorodithioate insecticides established the analogous S-methylation pathway for ethion, malathion, phenthoate, phosalone, and phosmet in mice. Thus, metabolism of O,O-dialkyl phosphorodithioate insecticides in mammals is shown here for the first time to yield S-methyl phosphorodithioates and phosphorothiolates from in vivo S- methylation of the intermediate O,O-dialkyl phosphorodithioic acids.
