Phosphorothioic Acids

This is an example of a reversible reaction the standard electrode potential of the 2PS/PSSP + 2c couple is zero at pH 7. The oxidation kinetics are simple second-order and the presence of a radical intermediate (presumably PS-) was detected. Reaction occurs in the pH range 5 to 13 with a maximum rate at pH 6.2, and the activation energy above 22 °C is zero. The ionic strength dependence of 2 afforded a value for z Zg of 9 from the Bronsted relation 

Several of these features remain unexplained but it is clear that here we have an example of a relatively well-behaved reversible electron transfer reaction involving radical intermediates. 

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Phosphoric Acid and Phosphorothioic Acid Anhydrides. The aUphatic organophosphoms esters originally developed by Schrader (27) are extremely toxic to mammals and are largely of historic interest. Tetraethyl pyrophosphate [107-49-3] (40) (bp 104—110°C at 10.7 Pa, d 1.185, vp 6.1 mPa at 30°C) is miscible with water and hydrolyzes very rapidly with a half-life of 6.8 h at 25°C. The rat LD qS ate 1.1 (oral) and 2.4 (dermal) mg/kg. 

Aliphatic Phosphorothioate Esters. Many of the eady developments of OP insecticides were simple esters of phosphorothioic acid, (H0)2P(0)SH, and phosphorodithioic acid, (HO)2P(S)SH. 

Phosphorothioic acid, o, o-dlethyl-o- 4-nitrophenyl) ester) Pentachlorophenol (PCP)... 

Chemical name Phosphorothioic acid O.O-diethyl 0-(3,5,6-trichloro-2-pyridinyl) ester... 

Diazinon is rapidly biotransformed and excreted in mammals. Estimated half-times of diazinon persistence were 6 to 12 h in rats (Anonymous 1972) and dogs (Iverson et al. 1975). Most of the diazinon metabolites were excreted in the urine as diethyl phosphoric add and diethyl phosphorothioic acid in dogs (Iverson et al. 1975), and as hydroxy diazinon and dehydrodiazinon in sheep (Machin et al. 1974). 

Diazinon (phosphorothioic acid 0,0-diethyl 0-(6-mcthyl-2-(l-mcthylcthyl)-4-pyrimidinyl) ester) is an organophosphorus compound with an anticholinesterase mode of action. It is used extensively to control hies, lice, insect pests of ornamental plants and food crops, as well as nematodes and soil insects in lawns and croplands. Diazinon degrades rapidly in the environment, with half-time persistence usually less than 14 days. But under conditions of low temperature, low moisture, high alkalinity, and lack of suitable microbial degraders, diazinon may remain biologically active in soils for 6 months or longer. 

Chemical names Phosphorothioic acid 0-[4-[(dimethylamino) sulfonyl], phenyl] 0,0-dimethyl ester Phosphorothioic acid, 0,0-dimethyl-, O-ester with p-hydroxy-/V,/V-dimethylbenzene sulfonamide Phosphorothioic acid, 0,0-dimethyl O-p-(dimethylsulfamoyl) phenyl ester O-Dimethyl hydrogen phosphorothioate, O-ester with p-hydroxy-/V,/V-dimethylbenzenesulfonamide 0-[4-1 (Dimethylamino) sulfonyl] phenyl phosphorothioic acid O.O-dimethyl ester O,O-Dimethyl O, p-(N,N-dimethylsulfamoyl) phenyl phosphorothioate O, p-(Dimethylsulfamoyl) phenyl O.O-dimethyl phosphorothioate p-(Dimethylsulfamoyl)phenyl dimethyl phosphorothioate O.O-dimethyl 0-[p-(dimethylsulfamoyl)-phenyl] phosphorothioate Dimethyl p-(dimethylsulfamoyl) phenyl phosphorothionate O.O-dimethyl-O, p-(dimethylsulfamoyl) phenyl phosphorothionate... 

The deselenization of t-butyl phenylphosphinoselenoic acid by Raney nickel is highly stereoselective, allowing a stereochemical correlation between the selenoate and the analogous phosphorothioic acid through a common intermediate.125... 

The hydrolysis half-life in three different natural waters was approximately 48 d at 25 °C (Macalady and Wolfe, 1985). At 25 °C, the hydrolysis half-lives were 120 d at pH 6.1 and 53 d at pH 7.4. At pH 7.4 and 37.5 °C, the hydrolysis half-life was 13 d (Freed et al, 1979). At 25 °C and a pH range of 1-7, the hydrolysis half-life was about 78 d (Macalady and Wolfe, 1983). However, the alkaline hydrolysis rate of chlorpyrifos in the sediment-sorbed phase were found to be considerably slower (Macalady and Wolfe, 1985). In the pH range of 9-13, 3,5,6-trichloro-2-pyridinol and 0,0-diethyl phosphorothioic acid formed as major hydrolysis products (Macalady and Wolfe, 1983). The hydrolysis half-lives of chlorpyrifos in a sterile 1% ethanoFwater solution at 25 °C and pH values of 4.5, 5.0, 6.0, 7.0, and 8.0 were 11, 11, 7.0, 4.2, and 2.7 wk, respectively (Chapman and Cole, 1982). 

Photolytlc. Malathion absorbs UV light at wavelengths more than 290 nm indicating direct photolysis should occur (Gore et al, 1971). When malathion was exposed to UV light, malathion monoacid, malathion diacid, 0,0-diethyl phosphorothioic acid, dimethyl phosphate, and phosphoric acid were formed (Mosher and Kadoum, 1972). 

The following metabolites were identified in a soil-oat system paraoxon, aminoparathion, 4-nitrophenol, and 4-aminophenol (Lichtenstein, 1980 Lichtenstein et al., 1982). Mick and Dahm (1970) reported that Rhizobium sp. converted 85% [ CJparathion to aminoparathion and 10% diethyl phosphorothioic acid in 1 d. 

Synonyms AI3-23284 Blitex BRN 1885571 Caswell No. 724 Dermafos Dermaphos Dimethyl trichlorophenyl thiophosphate 0,0-Dimethyl-0-2,4,5-trichlorophenyl phosphorothio-ate 0,0-Dimethyl 0-(2,4,5-trichlorophenyl)thiophosphate Dow ET 14 Dow ET 57 Ectoral EINECS 206-082-6 ENT 23284 EPA pesticide chemical code 058301 ET 14 ET 57 Etrolene Fenchlorfos Fenchlorophos Fenchchlorphos Karlan Korlan Korlane Nanchor Nanker Nankor NSC 8926 QMS 123 Phenchlorfos Phosphorothioic acid, 0,0-dimethyl 0-(2,4,5-trichlorophenyl) ester Remelt Ronne Rovan Smear, Trichlormetaphos Trichlorometafos Trolen Trolene Trolene 20L Troline Viozene. 

Phosphoric acid, tri-2-tolyl ester, see Tri-o-cresyl phosphate Phosphorothioic acid, 0,0-diethyl 0-(4-nitrophenyl) ester, see Parathion... 

Phosphorothioic acid, 0,0-dimethyl 0-(2,4,5-trichloro-phenyl) ester, see Ronnel... 

Diethyl phosphate, see Sulfotepp Diethyl phosphoric acid, see Diazinon. Parathion Diethyl phosphorothioate, see Diazinon 0,0-Diethyl phosphorothioic acid, see Chlorpyrifos, Diazinon. Malathion, Parathion Diethyl sulfide, see Chlorpyrifos Diethyl thiomalate, see Malathion Diethylthiomaleate, see Malathion Diethylthiophosphoric acid, see Diazinon. Parathion Diethyl-0-thiophosphoric acid, see Parathion... 

Dimethyl phosphorodithioic acid, see Malathion 0,0-Dimethyl phosphorophosphate, see Methoate Dimethyl phosphorothioate, see Malathion, Parathion 0,0-Dimethyl phosphorothioate, see Malathion 0,5-Dimethyl phosphorothioate, see Acephate Dimethyl phosphorothioic acid, see Dimethoate Dimethyl phosphorothionic acid, see Malathion 0,0-Dimethyl phosphorothionic acid, see Malathion Dimethyl sulfide, see Methyl mercaptan Dimethyl thiophosphate, see Malathion Dimethyl thiophosphoric acid, see Malathion Dimethyl triclopyr-aspartate, see Triclonvr Dimethyl triclopyr-glutamate, see Triclopvr... 

Ethyl-7-nitro-4,5-dimethyl-3-hydroxy-2,3-dihydro-benzimidazole, see Pendimethalin 0-Ethyl-0-(p-nitrophenyl)phosphorothioic acid, see Parathion... 

Chloroform, Chloropicrin, 1,1-Dichloroethylene, Endrin, Hexachlorocyclopentadiene, Methyl chloride. Methylene chloride, Tetrachloroethylene, 1,1,1 -Trichloroethane, Trichloroethylene Phosphine, see Pentachlorobenzene, Phorate Phosphoric acid, see Dichlorvos, Ethephon. Glvphosate. Malathion, Mevinphos, Parathion, Sulfotepp, Tributyl phosphate, Trichlorfon Phosphoric acid, dimethyl ester, see Mevinphos, Oxvdemeton-methvl Phosphorothioic acid, see Parathion Photoaldrin, see Aldrin Photoaldrin chlorohydrin, see Dieldrin Photodieldrin, see Aldrin, Dieldrin Photoheptachlor, see Heptachlor Photoketoaldrin, see Aldrin Phthalaldehyde, see Naphthalene Phthalaldehydes, see Tolnene Phthalic acid, see Anthracene, Benzo[a]anthracene, Benzyl bntyl phthalate, Dichlone. Diethyl phthalate, Dimethyl phthalate, Naphthalene, Naptalam. I ene... 

Bi analogues. Also omitted are the phosphorothioic acid derivatives, such as the insecticide diazinon, and related compounds. Unnatural nucleoside derivatives have been given only brief mention, since the base, rather than the sugar, is our target in this review. 

Synonyms Baycid Baytex Entex Lebaycid Mercaptophos phosphorothioic acid 0, 0-dimethyl 0-(3-methyl-4-(methylthio)phenyl) ester... 

Parathion is also metabolized to diethyl phosphorothioic acid and -nitrophenol in a reaction requiring a cytochrome P-4Jg-containing monooxygenase enzyme system (, 4). Studies with H. 0 have indicated that water in addition to molecular oxygen and NADPH is required in this reaction ( ). Diethyl phosphate and -nitro-phenol can also be formed from parathion in a monooxygenase-catalyzed reaction (6). 

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