Metabolism and balance studies of [14C]monolinuron after use in spinach followed by cress and potato cultures

[¹⁴C]Monolinuron was added to soil which was then successively cropped with spinach, cress, and potatoes. Incubation was carried out in a closed system which allowed recoveries even of volatile degradation products and gave an overall recovery of 96% of the applied radioactivity at the end of the experiment. The spinach was found to contain 4.1% of the applied activity; the cress, 5.6%; old potatoes + leaves, 9.5%; new tubers, 1%; and the soil, 68.6%. The total amount of [¹⁴C]carbon dioxide liberated was 5.3%. The quantitative separation and characterization of the extractable radioactivity in spinach yielded 10.6% as unaltered monolinuron, 12% as 4-chlorophenylurea plus 4-chlorophenyl-hydroxymethylurea, 3.7% as 4-chlorophenylmethylurea, 1.4% as 4-chlorophenyl-hydroxymethyl-methoxyurea, 1.1% as 4-chlorophenyl-methoxyurea, and 71.2% as polar metabolites. Of these polar metabolites, 67.1% were cleaved with β-glucosidase, resulting in 2.9% unknown aglucone, 48.1% 4-chlorophenyl-hydroxymethyl-methoxyurea, and 16.1% 4-chlorophenyl-hydroxymethylurea. Similar results have been obtained in cress and potatoes. The soil contained 58% of monolinuron residues and 4.7?6.5% of the same types of metabolites as were found in plants. Twenty-one percent were found as polar metabolites.     

Aus anderen Fachzeitschriften/Buchbesprechungen

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Aus anderen Fachzeitschriften/Buchbesprechungen     

Synthesis of anthelmintically active N-methylated amidoxime analogues of the cyclic octadepsipeptide PF1022A

The N-methylated amidoxime analogues of the cyclic octadepsipeptide PF1022A represent novel derivatives with activity against Trichinella spiralis Owen and Nippostrongylus brasiliensis Lane in vitro and against parasitic nematodes in mice and sheep. Some of them show better activity against Hymenolepis nana Siebold, Heterakis spumosa Schneider and Heligmosomoides polygyrus Dujardin in mice than the natural product PF1022A. In particular an improved efficacy against Haemonchus contortus Rudolphi and Trichostrongylus colubriformis Giles in sheep compared to the potent cyclic octadepsipeptide PF1022A and its mono-thionated derivative has been observed. Here we report on a specific modification at the N-methyl amide linkage by using the mono-thionated PF1022A, resulting in novel anthelmintically active backbone analogues of PF 1022A.     

Gaschromatographie der Pflanzenschutzmittel

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