0,0-Dimethyl phosphorodithioic acid

The feed materials for malathion manufacture are 0,0-dimethyl phosphorodithioic acid and diethyl maleate or fumarate which react according to the equation ... 

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... 

American Cyanamid in the early 1950s was therefore welcome. Malathion is widely used today. It is synthesized by condensing diethyl maleate with the 0,0-dimethyl phosphorodithioic acid obtained as previously discussed. 

At 87 °C and pH 2.5, malathion degraded in water to malathion a-monoacid and malathion P-monoacid. From the extrapolated acid degradation constant at 27 °C, the half-life was calculated to be >4 yr (Wolfe et al., 1977a). Under alkaline conditions (pH 8 and 27 °C), malathion degraded in water to malathion monoacid, diethyl fumarate, ethyl hydrogen fumarate, and QO-dimethyl phosphorodithioic acid. At pH 8, the reported half-lives at 0, 27, and 40 °C are 40 d, 36 h, and 1 h, respectively. However, under acidic conditions, it was reported that malathion degraded into diethyl thiomalate and 0,0-dimethyl phosphorothionic acid (Wolfe et al, 1977a). 

Dimethyl phosphorodithioate, see Malathion 0,0-Dimethyl phosphorodithioate, see Dimethoate Dimethyl phosphorodithioic acid, see Dimethoate. Malathion... 

In the 1970s, organophosphorus compounds became the leading type of insecticide. Over 40 such compounds have been registered in the United States as insecticides. The first organophosphorus insecticide was synthesized in 1938 and is known as tetraethyl pyrophosphate (TEPP). Another phosphate insecticide, Malathion is synthesized by condensing diethyl maleate with the o,o-dimethyl phosphorodithioic acid. 

Cassaday (1950), Shostakovski et al. (1951) and Melnikov et al. (1952) investigated extensively the addition reactions of dialkyl phosphorodithioic acids to unsaturated dicarbonic acid esters, and found that the dialkyl phosphorodithioic acids are added at the double bond in the same way as are mercaptans. This reaction was used by Cassaday (1950) who prepared 0,0-dimethyl-S-(l,2-dicarbethoxy)-ethyl phosphorodithioate by the addition reaction of dimethyl phosphorodithioic acid and maleic acid diethyl ester. This compound, known by the name malathion (89), became one of the most important phosphorus ester insecticides because of its low toxicity to warm-blooded animals. 

The technical production of malathion can be carried out in a single-step process without the intermediate preparation of dimethyl phosphorodithioic acid, starting from phosphorus pentasulfide, methanol and maleic acid diethyl ester (Matolcsy and Oswald, 1955 1957). 

Diacid pH 8 0.018 1.8 X 10 445 day Thio succinic acid, dimethyl phosphorodithioic acid... 

Day (1991) reported that the hydrolysis prodncts are dependent upon pH. In basic solutions, malathion hydrolyzes to diethyl fumarate and dimethyl phosphorodithioic acid (Bender, 1969 Day, 1991). Dimethyl phosphorothionic acid and 2-mercaptodiethyl succinate formed in acidic solutions (Day, 1991). The hydrolysis half-hves of malathion in a sterile 1% ethanol/water solution at 25°C and pH valnes of 4.5, 6.0, 7.0 and 8.0, were 18, 5.8, 1.7 and 0.53 weeks, respectively (Chapman and Cole, 1982). The reported Itydrolysis half-lives at pH 7.4 at 20 and 37.5°C were 10.5 and 1.3 days, respectively. At 20°C and pH 6.1, the hydrolysis half-life is 120 days (Freed et al., 1979). Konrad et al. (1969) reported that after 7 days at pH values of 9.0 and 11.0, 25 and 100% of the malathion was hydrolyzed. Hydrolysis of malathion in acidic and alkahne (0.5 M sodium hydroxide) conditions gives (CH30)2P(S)Na and (CH30)2P(S)0H (Sittig, 1985). 

Diethyl mercaptosuccinic acid O.O-dimethyl phosphorodithioate. see Malathion Diethyl mercaptosuccinate. 0,0-dimethyl phosphorodithioate. see Malathion... 

Chemical Name 0,0-dimethyl S-phthalimidomethyl phosphorodithioate V-dimethoxyphosphino-thioylthiome-thyl)phthalimide 5-[(l,3-dihydro-l,3-dioxo-2/f-isoindol-2-yl)methyl] 0,0-dimethyl phosphorodithioate phospho-rodithioic acid, A-[(l,3-dihydro-l,3-dioxo-2f/-isoindol-2-yl)methyl] 0,0-dimethyl ester Uses nonsystemic acaricide and insecticide. 

SYNS S-(6-CHLORO-3,4-DIHYDRO-2H-l-BENZO-THIOPYRAN-4-YL) o,o-DIMETHYL PHOSPHORO-DITHIOATE PHOSPHORODITHIOIC ACID, S-(6-CHLORO-3,4-DIHYDRO-2H-l-BENZOTHIOPYRAN-4-YL) 0,0-DIMETHYL ESTER... 

SYNS S-(2-(ACETYLAMIN0)ETHYL)-0,0-DIMETHYL PHOSPHORODITHIOATE AiWHOS CP 49674 DAEP 0,0-DlMETHYL-S-(2-ACET AMID0ETH X) ESTER PHOSPHORODITHIOIC ACID 0,0-DIMETH-YL-S-(2-ACETYLAMINOETHYL) PHOSPHORODITHIOATE N-((0,0-DIMETHYLPH0SPH0R0DITHI0YL)-ETHYL)ACETAMIDE ENT 27,346 MONSANTO CP-49674 NSC-190945 PHOSPHORODITHIOIC ACID, 0,0-DIMETHYL ESTER, S-ESTER with N-(2-MERCAPTOETHYL)ACETAhnDE... 

DIETHYL MERCAPTOSUCCINTC ACID-0,0-DIMETHYL PHOSPHORODITHIOATE see MAK700 DIETHYL MERCURY see DJ0400... 

PHOSPHORODITHIOIC ACID, 0,0-DIMETHYL-S-(2-ETHYLTHIO)ETHYL ESTER see PHI500 PHOSPHORODITHIOIC ACID-0,0-DIMETHYL-S-(2-(METHYLAMINO)-2-OXOETHYL) ESTER see DSP400 PHOSPHORODITHIOIC ACID-S,S -l,4-DIOXANE-2,3-DIYL-0,0,0. 0 -TETRAETHYL ESTER see DVQ709 PHOSPHORODITHIONIC ACID, S-2-(ETHYLTHIO)ETHYL-0,0-DIETHYL ESTER see DXH325... 

PHTHAUNODE, N-(HYDROXYMETHYL)- see HMPlOO PHTHAUNDDINODE see DNE400 PHTHAUMID0-0,0-DIMETHYL PHOSPHORODITHIOATE see PHX250 2-PHTHAUMIDOGLUTARIC ACID ANHYDRIDE see PHXlOO... 

In an examination of the stereochemical course of addition of phosphorodithioic acids to 1,2-unsaturated pento- and hexopyranoses, S-deuterated 0,0-dimethyl- and 0,0-bis(2,2-dimethyl-propyl) phosphorodithioates were prepared and reacted with D-glucal. These reactions were found to be fully stereoselective at both reaction centers C-l and C-2 and afforded S-D-ara-binopyranosyl phosphorodithioates 8 and 9 in quantitative yield deuterated at C-2 of the pyranosyl ring14. s... 

DIMETHYL S-((4-OXO-1,2,3-BENZOTRIAZIN-3(4H -YL)METHYL) ESTER PHOSPHORODITHIOIC ACID 0,0-DIMETHYL S-((4-OXO-1,2,3-BENZOTRIA2IN-3(4H)-YL)METHYL) ESTER PHOSPHORODITHIOIC 0,0-DIMETHYL ESTER. S-ESTER WITH 34MERCAPTOMETHYL -1,2,3-BENZOTRIAZIN -4(3H)-ONE PHOSPHORODITHIOIC ACID... 

P-Hydroxy-2P-tropanecarboxylic Acid Methyl Ester, Benzoate 3-Hydroxypropene 3-Hydroxyquinuclidine 3-Hydroxyquinuclidine Benzilate 3-(Mercaptomethyl)-l,2,3-benzotriazin-4(3H)-one 0,0-Dimethyl Phosphorodithioate 3-(Mercaptomethyl)-l,2,3-benzotriazin-4(3H)-one 0,0-Dimethyl Phosphorodithioate S-Ester 3-Methyl-4-(dimethylamino)phenyl Methylcarbamate... 

Methylethyl)amino]-2-oxoethyl] Ester Phosphorodithioic Acid 0,0-Dimethyl S-[(4-Oxo- A160 Industrial 152... 

The other members of this family of compounds are phosphorodithioic acid derivatives. Of these, menazon, 0,0-dimethyl-S-(4,6-diamino-l,3,5-triazin-2-yl)-methyl phosphorodithioate (78), distinguishes itself by its low toxicity to warmblooded animals. It is prepared by cyclisation of biguanide and ethyl chloroacetate, upon which the 2-chloromethyl-4,6 iaminotriazine formed is reacted with sodium 0,0-dimethyl phosphorodithioate (Anonym, 1958). 

Cassaday c/ al. (1948) prepared several S-carbamoylmethyl phosphorodithioates by the reaction of the salts of 0,0-dialkyl phosphorodithioic acids with various N-substituted chloroacetamides, and investigated their biological properties. Of these, practical importance has been attained by O.O-dimethyl-S-(N-methylcarbamoyl)-methyl phosphorodithioate, known by the name dimethoate (85). 

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