Parathion Absorption, Translocation, and Conversion to Paraoxon in Bean Plants

Abstract

the R, values of the metabolites in butanol-ammonia-water indicated that the minor metabolite had been converted to dicamba. I n the case of the major metabolite, the saponification yielded a compound which differed from the original. This suggested that the aromatic ring had been hydroxylated.By the microcoulemetric method for chlorine determination, the ratio of to chlorine for the major metabolite was approximately 80% of dicamba. This indicated that if the benzoic acid structure still was intact, the major metabolite, contained t\vo chlorine atoms per molecule. By trapping the I4CO2 from the combustion of the major metabolite, the chlorine, measured by the microcoulometric gas chromatography. was found to come from this metabolite.The identification of the minor metabolite was afforded further by comparing its R, values, as detected on a strip scanner, with those of nonlabeled 3.6-dichlorosalicylic acid, which was detected via a phenolic spray reagent.This reagent consisted of mixing equal volumes of 1% ferric Parathion Absorption, Translocation, and Conversion to Paraoxon in Bean Plantschloride solution with a 1% potassium ferricyanide solution. The '4C-methoxylabeled dicamba gave no labeled minor metabolite at the R,'s expected for dichlorosalicylic acid on the four chromatography systems, which indicated that the methoxy group was present in the major metabolite.The intermediate product in the synthesis of 5-hydroxy dicamba from dicamba was isolated and elemental analysis obtained. Methyl-5-amino-2methoxy -3 -6dichlorobenzoate gave pale yellow plates, m.p 108' C.! from ethanol. Found 43.2;3.7. C9H903NC1? requires C=43.2 and H = 3 . 6 .Gas liquid chromatography. infrared spectrophotometry, and mass spectrometry were used to identify the major metabolite as being 5-hydroxy-2methoxy-3,6-dichlorobenzoic acid. The retention times of the methylated metabolite and methylated 5-hydroxy dicamba are found in Table 111. To obtain an IR spectrum, a sufficient amount of the methylated metabolite was purified further by means of a GLC fraction collector. 'This spectrum \vas compared with the IR spectrum of

Metabolism of an Insecticide Fenitrothion by Cunninghamella elegans ATCC36112

“…Two major degradation pathways are proposed: the first pathway occurs with the substitution of a S atom by an O atom, and the second pathway involves the hydroxylation of the organophosphate band. The reaction of oxidation to form the oxon derivatives is quite common in phosphorothioate pesticides, such as parathion, cyanox, and bromophos . FNTO (M3) has been the most common metabolite found in plants, animals, and microorganisms during the degradation of FNT. ,, In the presence of C.…”

Ultraviolet irradiation of fenitrothion and the synthesis of the photolytic oxidation products

“…In Canada, its main use is to control defoliators in forests.It is structurally similar to parathion, the ultraviolet (uv) photolysis of which has been extensively studied (Cook and Pugh, 1957; Frawley et al, 1958;Koivistoinen and Merilainen, 1963;El-Rafai and Hopkins, 1966; and Joiner and Baetcke, 1974). In hexane, both the P=S and the aryl methyl group were oxidized to give fenitrooxon and formylfenitrothion.…”

“…It is structurally similar to parathion, the ultraviolet (uv) photolysis of which has been extensively studied (Cook and Pugh, 1957; Frawley et al, 1958;Koivistoinen and Merilainen, 1963; El-Rafai and Hopkins, 1966;and Joiner and Baetcke, 1974). In contrast, little work has been carried out on the photolysis of fenitrothion.…”

Reviews of Environmental Contamination and Toxicology

“…The corresponding oxon was confirmed by GC analysis of com forage treated with emulsifiable concentrate formulation of (152) but its route of formation was ambiguous due to the harsh Soxhlet extraction (Bowman and Leuck 1971). Malathion (167) is considered to be also resistant to direct photolysis, and only hydrolysis of ester linkages is a dominant pathway (Awad et al 1967;EI-Refai and Hopkins 1972;Mostafa et al 1974). Metabolism of 14C_ and 32P-phenthoate (168) in Valencia orange leaves and fruit showed that the main degradation pathways on the surface were P=S oxidation to the oxon, stepwise hydrolysis at the S-C bond and carboxylate moiety to mandelic acid, and hydrolysis of the P-S bond followed by formation of disulfide (Takade et al 1976).…”