The Oxygen Analogs

Organic peroxides can decompose either homolytically into a pair of oxygen radicals or heterolytically to give an oxygen cation and 

The thermal decomposition of / -nitrotriphenylmethyl hydroperoxide in benzene gives -nitrophenol 32%, phenol 9%, -nitro-triphenylcarbinol 23%, -nitrobenzophenone 14%, and no benzo-phenone the decomposition in ether plus sulfuric acid gives -nitro-benzophenone 94% and phenol 81%.817 The latter reaction is very probably  

Again the mechanism as written is not meant to imply a completely free oxygen cation as the intermediate. A concerted ionization and rearrangement seems more likely. 

A similar mechanism is probable for the decomposition of decalyl perbenzoate.818 

The reaction goes faster in more polar solvents (a range of 106 in the rate constant) and parallels carbonium ion rearrangements in that respect. The effect of substituents in the para position of the benzoate group also suggests that the rate-determining step is the formation of an initial ion pair. The reaction is faster with the nitro than with the methoxyl substituent.819 820 The Hammett p value is 1.34. The activation parameters are not known for any but the unsubstituted member of the series however, and hence it is not known to what extent the relative rates depend upon the temperature. 

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Air samples collected in the Sacramento Valley area of California near sites where methyl parathion was heavily used on rice were analyzed by Seiber et al. (1989). Methyl parathion concentrations ranged from 0.2 (minimum detectable level) to 25.67 ng/m depending on the location and time of sampling. Methyl paraoxon, the oxygen analog of methyl parathion, was also detected at a maximum of 3.07 ng/m. The highest concentrations of both compounds were found at sites near locations of heaviest use. 

Because phenol is cheaper than nitrophenol, it might cost less to condense phenol with this chloro intermediate, followed by nitration with nitric acid. This method of preparing the oxygen analog can be used as shown in Equation 40. Still another method of preparation is shown in Equation 41. 

The colorimetric method of Averell and Norris (3) for estimation of parathion is also applicable to the oxygen analog, which gives a magenta color of identical absorption peak (16). The polarographic method of Bowen and Edwards (6) is also applicable to the analysis of this ester. 

Diethyl p-nitrophenyl phosphate, the oxygen analog of parathion, was investigated to ascertain whether it would interfere, if present, in the determination of parathion. It was found, however, under the conditions used in this method to have a decomposition potential of —0.37 volt and a half-wave potential of —0.47 volt. 

The oxygen analog, famoxon, is more toxic than the parent chemical... 

Three different pathways are associated with the metabolism of disulfoton (I) oxidation of the thioether sulfur to produce sulfoxides and sulfones (2) oxidation of the thiono sulfur to produce the oxygen analogs and (3) hydrolysis of the P-S-C linkage to produce the corresponding phosphorothionate or phosphate (WHO 1976) (see Figure 2-3). These pathways have been elucidated from data obtained in humans exposed to disulfoton and from in vivo and in vitro metabolism studies in rats and mice. 

Residues identified on field-treated kale other than malathion included the oxygen analog and the impurity identified by nuclear magnetic resonance and mass spectrometry as ethyl butyl mercaptosuccinate, 5-ester with 0,0-dimethyl phosphorodithioate. This compound did not form as an alteration product of malathion but was present in the 50% emulsifiable concentrate (Gardner et al, 1969). 

CASRN 60-51-5 molecular formula C5H12NO3PS2 FW 229.30 Soil Duff and Menzer (1973) reported that in moist soils, dimethoate is converted to the oxygen analog, dimethoxon (0,0-dimethyl-5-(W-methylcarbamoylmethyl) phosphorothiolate) and two unidentified metabolites. The degradation rate of dimethoate in three different soils increased almost two-fold with a 10 °C increase in temperature (Kolbe et al., 1991). The reported half-lives of dimethoate in a humus-rich sandy soil, clay loam, and heavy clay soil at 10 and 20 °C were 15.3, 10.3, 15.5 d and 9.7, 4.8, 8.5 d, respectively. 

The highly substituted derivative 186, in the form of the potassium salt, has been recommended for use in detonators in place of the more dangerous mercury fulminate. l,2,3-Benzotriazine-4-thione (39, R — H) has been used in photographic transfer emulsions as an inhibitor and toning agent, and heavy metal salts of the oxygen analog 10, R = H are employed as photodevelopable emulsions. The latter compound is also claimed to be useful as a stabilizer in olefin polymers and as an antioxidant in certain other polymers. Dimeric derivatives of 10 have... 

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