Transformation of (14)C-pyrimidynyloxybenzoic herbicide ZJ0273 in aerobic soils.
A soil metabolism study of propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate (ZJ0273), a novel broad-spectrum herbicide, was carried out using (14)C labeled on two different rings, i.e., [pyrimidine-4,6-(14)C] ZJ0273 and [benzyl-U-(14)C] ZJ0273. Ultralow liquid scintillation counting and LC-MS/MS were used to identify the degradation intermediates and quantify their dynamics in aerobic soils. Four aromatic intermediates, 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoic acid (M1), 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzamido)benzoic acid (M2), 2-(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (M3), and 4,6-dimethoxypyrimidin-2-ol (M4), were identified and their identity was further confirmed against authentic standards. Analysis of metabolites suggested two degradation pathways: (1) Upon loss of the propyl group, M1 was produced via hydrolysis of propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate after which the C-N bond between rings A and B was cleaved by oxidation and biochemical degradation to yield M3, which was further converted into M4 and finally mineralized to CO(2); and (2) the first step was the same as in pathway 1, but M1 first underwent a carbonylation to form M2. The C-N bond between rings A and B of M2 was cleaved by hydrolysis to yield M3. Dynamic changes in the four metabolites in aerobic soils were also investigated by HPLC coupled analysis of radioactivity of isolated peaks. After a 100-day incubation, 1.7-9.7% of applied (14)C was found as M1, 0.3-1.1% as M2, 14.5-20.9% as M3, and 3.7-6.7% as M4 in the soils, and pH appeared to be the most influential soil property affecting the formation and dissipation of these metabolites.
Haiyan
Wang
W
Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture, Zhejiang University, Hangzhou 310029, China.
Zhiyang
Yu
Y
Ling
Yue
Y
Ailiang
Han
H
Yanfei
Zhang
Z
Juying
Li
L
Qingfu
Ye
Y
Zhengmin
Yang
Y
Long
Lu
L
D000332:Aerobiosis; D000383:Agriculture; D001565:Benzoates / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D029741:Brassica rapa / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D012588:Scintillation Counting; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
D001565:Benzoates; D002250:Carbon Radioisotopes; D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants; C543844:propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate