152-20-5Relevant academic research and scientific papers
Reactions of diazoacetates with phosphate triesters and thiophosphate triester: >P+-O-C-P+-S-C-< intermediacy formation
Popov, Konstantin A.,Polozov, Alexander M.,Tcherezov, Sergei V.
, p. 1859 - 1862 (1997)
Diazoacetates 1a,b undergo BF3 · OEt2 catalyzed carbenoid attack on the oxygen of the phosphoryl double bond of phosphate triesters 2a-c or on the sulfur of thiophosphoryl double band of thiophosphate 9 to form corresponding O-alkoxycarbonylmethylphosphates 3a-c or S-alkoxycarbonylmethylphosphate 13.
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 (1996)
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.
Synthesis, characterization and photocatalytic activity of Ag-TiO2 nanoparticulate film
Ramacharyulu,Praveen Kumar,Prasad,Srivastava
, p. 1309 - 1314 (2015/02/02)
Ag-TiO2 nanoparticulate film was synthesized by dip coating followed by adsorption and photoreduction in UVA light, characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive analysis of X-rays, glancing angle X-ray diffractometry and UV-Vis absorption spectrophotometry techniques. The data indicated the presence of TiO2 particles of anatase phase of size varying from 5-15 nm, Ag nanoparticles of size varying from 10-20 nm, and also indicated the added visible light activity in Ag-TiO2 nanoparticle films. Photocatalytic degradation of methyl parathion (O,O-dimethyl O-(4-nitrophenyl) phosphorothioate), a well known pesticide in aqueous solution was studied using Ag-TiO2 nanoparticulate film and the data was compared with TiO2 nanoparticulate film. Photocatalytic degradation reactions demonstrated pseudo first order behaviour. Methyl parathion was found to be degraded initially to paraoxon which further was degraded to p-nitrophenol, trimethyl ester of phosphoric acid, trimethyl ester of phosphothioic acid, and finally to phosphate ion. Minute amounts of carbon dioxide and acetaldehyde were also detected. This journal is
A new method of introducing SCH3 and SCD3 groups to phosphorothioates
Liu, Tianzhen,Cui, Xiaoxue,Yu, Zhifang,Li, Chunbao
experimental part, p. 606 - 611 (2012/06/01)
A new synthesis of phosphorothioates starting from phosphites and cyanuric chloride (TCT)-activated DMSO is reported herein. This method enables the incorporation of SCH3 and SCD3 groups into phosphorothioates in good yields. The labeling purities of the products are excellent.
Photolysis of methyl-parathion thin films: Products, kinetics and quantum yields under different atmospheric conditions
Segal-Rosenheimer, Michal,Dubowski, Yael
scheme or table, p. 193 - 202 (2010/10/01)
The present study focuses on the photodegradation of methyl-parathion thin films, an organophosphate insecticide, under different atmospheric conditions. The latter include nitrogenated, oxygenated and ozonated atmospheres, under low and high relative humidity conditions. Addition of oxygen to the atmospheric mixture did not seem to affect the reaction rates and quantum yields. Relative humidity affect was minor, with a small enhancement in reaction rate under 254. nm radiation. The addition of ozone (to either dry or humid atmosphere), at all concentrations tested, largely enhanced degradation rates. In the absence of ozone, the obtained quantum yields for photolysis of methyl-parathion thin films under 254 and 313. nm were 0.024 ± 0.007 and 0.012 ± 0.005, respectively. These values are higher than the values previously reported for solutions of methanol and water. Although the presence of molecular oxygen and water vapors did not seem to affect much the reaction rates, it did have a certain effect on the resulted products. More polar products were obtained under oxygenated and ozonated atmospheres, as well as dimers under ozone conditions. The reaction on thin films has yielded more toxic products than usually found in solutions, adding alkylphosphate esters in addition to the oxons formed normally.
Reduction of dichlorvos and omethoate residues by O2 plasma treatment
Bai, Yanhong,Chen, Jierong,Mu, Hui,Zhang, Chunhong,Li, Baoping
experimental part, p. 6238 - 6245 (2010/07/06)
A practical, inexpensive, and green chemical process is greatly needed for degrading pesticides in food and environmental water. In this work, the impact of O2 plasma treatment on reduction of dichlorvos (DDVP) and omethoate in maize was determ
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.
Preparation of organohalosilanes
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, (2008/06/13)
In an industrial process for preparing organohalosilanes by reacting metallic silicon particles with an organohalide in the presence of a copper catalyst, a contact mass composed of the metallic silicon and the catalyst further contains an effective amount of a phosphine chalcogenide compound. The invention drastically increases the silane formation rate and the utilization of silicon without lowering the selectivity of useful silane.
Stereoselective and chemoselective oxidation of phosphorothionates using MMPP
Jackson,Berkman,Thompson
, p. 6061 - 6064 (2007/10/02)
MMPP (monoperoxyphthalic acid, magnesium salt) converts phosphorothionates to the corresponding oxons in good yields with excellent chemoselectivity and stereoselectivity.
Solvolysis of allylic isoprene phosphorothioate esters. A mechanistic study of the thiono → thiolo rearrangement
Poulter, C. Dale,Mautz, Douglas S.
, p. 4895 - 4903 (2007/10/02)
The reactions of O,O-dimethyl O-geranyl phosphorothionate (1-OPS(OMe)2), O,O-dimethyl S-geranyl phosphorothiolate (1-SPO(OMe)2), and O,O-dimethyl S-lianlyl phosphorothiolate (2-SPO(OMe)2) were studied in 65:35 TFE/water. Solvolysis of 1-OPS(OMe)2 at 20°C gave substantial amounts of thiolo isomers 1-SPO(OMe)2 and 2-SPO(OMe)2, along with smaller quantities of solvent addition products. At 40-65deg;C, rearrangement of linalyl phosphorothiolate 2-SPO(OMe) to geranyl phosphorothiolate 1-SPO(OMe)2 reacted at 90-120°C to give substitution products and 1-SPO2(OMe)2, formed by hydrolysis of a methyl. The relative reactivities of 1-OPS(OMe)2, 1-SPO(OMe)2, 2-SPO(OMe)2 are 1:(3 × 10-7):(6 × 10-3), respectively. From a combination of kinetic and trapping experiments, we estimate that 1-OPS(OMe)2 is 11 kcal/mol less stable than its thiolo isomer. A dissociative mechanism with ion-paired intermediates is proposed for the thiono → thiolo rearrangements, and the utility of the phosphorothioate moiety as a tool for studying reactions involving ion pairs is discussed.
