Chlorimuron ethyl

Soybeans CZE UV 11-85 ugkg- 50 mM acetate Acifluorfen, 2,4-D, bentazone, thifensulfuron-methyl, chlorimuron-ethyl, imazaquin 129... 

There are several commercially available sulfonylurea herbicides that contain a 2-pyrimidine group <2006H(68)561>. These compounds, which function by inhibition of acetolactate synthase (ALS), an enzyme involved in the early stage of branched-chain amino acid synthesis, include sulfometuron-methyl 1095, primisulfuron-methyl 1096, chlorimuron-ethyl 1097, bensulfuron-methyl 1098, ethoxysulfuron 1099, nicosulfuron 1100, and pyrazosulfuron-ethyl 1101. Related nonsulfonylureas include the sulfide pyrftalid 1102 and the ether pyriminobac-methyl 1103. 

Soybean Chlorimuron-ethyl + thifensulfuron-methyl Post Good j... 

General LC/MS Conditions for Sulfonylurea Multiresidue Analysis. We have developed general thermospray LC/MS conditions for the purpose of separating and detecting six different sulfonylurea herbicides. These conditions can be used as a guide fra- a variety of LC/MS residue applications which may require the analysis of one or more of these herbicides. Our procedure includes GLEAN (chlorsulfuron), ALLY (metsulfuron methyl), HARMONY (thiameturon) and EXPRESS cereal herbicides, CLASSIC (chlorimuron ethyl) soybean herbicide and OUST (sulfometuron-methyl) noncrop land herbicide. (Structure 1)... 

Site-directed mutagenesis was used to make additional amino acid substitutions at these sites in yeast ALS. At some of the sites, e.g. alall7, prol92, or trp586, nearly any substitution for the wild type amino acid that was tested resulted in a herbicide-resistant enzyme (Table I). Each of the mutant enzymes was characterized by enzyme assays to compare its activity, and its sensitivity to the sulfonylurea herbicide chlorimuron ethyl, to the wild type enzyme. These analyses have indicated that some of the mutations have little adverse effect on the activity of the enzyme, while decreasing sensitivity to the herbicide from three to greater than one thousandfold. The characteristics of these mutant enzymes were further evaluated in vivo in order to investigate the utility of particular herbicide/mutant enzyme combinations (Falco et al., manuscript in preparation). 

FIGURE 4 Results from a field test of herbicide-resistant tobacco lines, conducted in North Carolina in 1987 in conjunction with Northrup King Co. The row of plants to the right of center contains elite tobacco lines that were transformed with the mutant tobacco ALS gene from the herbicide-resistant Hra line, while the row to the left of center has non-transformed control plants. After treatments with the sulfonylurea herbicide chlorimuron ethyl at 4X normal field application rate, the weeds were killed, the non-transformed controls were severely injured and remained stunted, and the transformed plants remained as vigorous as the unsprayed controls. 

As a result, the sulfonylurea herbicides are more rapidly hydrolyzed in acidic waters and soils. Figure 2.11 illustrates the pH-rate profile for the hydrolysis of chlorimuron-ethyl at 45°C in buffered aqueous solution (Brown, 1990). 

The hydrolysis rate constant for chlorimuron-ethyl decreases over 150-fold as the pH increases from 4 to 7. Additionally, ionization affects water solubility. The water solubility of chlorimuron-ethyl increases from 11 to 1200 mg/L when the pH increases from 5 to 7 (Hay, 1990). Consequently, the sulfonylureas are expected to be much more persistent and more readily transported in basic aquatic ecosystems. 

Figure 2.11. Chlorimuron-ethyl hydrolysis rate constant versus pH at 45°C in buffered aqueous solution. From Hay (1990). (Reprinted by permission of the Society of Chemical Industry).

In yeast AHAS, spontaneous mutations at ten separate sites have each been shown to confer resistance to SUs [63, 64]. The X-ray crystal stmcture of yeast AHAS bound with chlorimuron ethyl revealed that nine of those residues make direct contact with the herbicidal molecule [54]. The authors studied the effects... 

Though this group of safeners appears to influence predominantly the GST system, Lamoureux and Rusness [41] reported that the safener BAS 145138 stimulated in maize not only the GSH conjugation but also the hydroxylation of the herbicide chlorimuron-ethyl. 

Halogen-containing Pyrimidinylsulfonylurea Herbicides The flrst halogenated member of this subclass is chlorimuron-ethyl (96 soya beans and peanuts, 9-13... 

CGA 92194 261 Charter 627 Chekker 58 Chess 1089 Chevalier 58, 60 Chinetrin 1202 chinomethionat 765 Chinook 987 Chipco Tristar 966-967 chlofluazuron 763 chlordane 760 chlorethoxyfos 760 chlorfenapyr 482, 513, 517, 763, 876, 880-884,1065, 1211 chlorfenson 868 chlorfenvinphos 760 chlorfluazuron 817, 1115, 1207—1208 chlorflurenol-methyl 402 chloridazon 196, 198, 378 chlorimuron 38,48 chlorimuron-ethyl 34—37, 39, 41,1224 chlorimuron-methyl 135 chlormephos 760 chlormequat 402 chlormequat-chloride 403-404 chloroneb 428... 

Fig. 5 - Displacement of the fluorescent probe FHMI by the imidazolinone and non-imidazolinone compounds, (left) Chemical structures of three imidazolinone class compounds and three non-imidazoline agrochemicals used to demonstrate the specificity of the fiber optic sensor, (right) Reduction of steady-state fluorescence by the various analytes. A 25 nM FHMI in casein/PBS solution was perfused to reach a steady state before a solution of 1 jlM compound was added to the FHMI, casein/PBS. Plot 1, imzamethabenz methyl 2, imazapyr 3 imzaaquin 4, chlorimuron ethyl 5, primisulfuron 6, sethoxydim. Reproduced with permission from reference 2, Copyright 1993 American Chemical Society.

---