Methyl-diuron

Pesticides containing methyl or other alkyl substituents maybe linked to N or 0 (i.e., N- or O-alkyl substitution). An N- or O-dealkylation catalyzed by microorganisms frequently results in loss of the pesticide activity. Phenylurea (see Chap. 1) becomes less active when microorganisms AT-demethylate the molecules (e. g., the conversion of Diuron to the normethyl derivative, Fig. 7). The subsequent removal of the second AT-methyl group renders the molecule fully nontoxic [169]. On the other hand, the microbial O-demethylation of Chloroneb creates the non-toxic product 2,5-dichloro-4-methoxyphenol (Fig. 7). 

Thom and Agg (1975) reported that diuron is amenable to biological treatment with acclimation. Soil Several degradation pathways were reported. The major products and reaction pathways include formation of l-methyl-3-(3,4-dichlorophenyl)urea and 3-(3,4-dichlorophenyl)urea via Wdealkylation, a 6-hydroxy derivative via ring hydroxylation, and formation of 3,4-dichloroaniline, 3,4-dichloronitroaniline, and 3,4-dichloronitrobenzene via hydrolysis and oxidation (Geissbiihler et al, 1975). 

Amresco acryl-40, see Acrylamide AMS, see a-Methylstyrene n-Amyl acetate, see Amyl acetate Amyl acetic ester, see Amyl acetate Amyl acetic ether, see Amyl acetate Amylene, see 1-Pentene a-n-Amylene, see 1-Pentene p-n-Amylene, see cis-2-Pentene cis-p-Amylene, see cis-2-Pentene frans-p-Amylene, see trans-2-Venlene sec-Amyl ethanoate, see Amyl acetate Amyl ethyl ketone, see 5-Methyl-3-heptanone Amyl hydride, see Pentane Amyl methyl ketone, see 2-Heptanone n-Amyl methyl ketone, see 2-Heptanone AN, see Acrylonitrile Anaesthetic ether, see Ethyl ether Anamenth, see Trichloroethylene Anduron, see Diuron Anesthenyl, see Methylal Anesthesia ether, see Ethyl ether Anesthetic ether, see Ethyl ether Anhydrous ammonia, see Ammonia Aniline oil, see Aniline Anilinobenzene, see 4-Aminobiphenyl Anilinomethane, see Methylaniline 2-Anidine, see o-Anisidine 4-Anisidine, see p-Anisidine 2-Anisylamine, see o-Anisidine... 

BRN 1912585, see Hexachlorobenzene BRN 1912384, see 2,4-Dinitrotoluene BRN 1913355, seep,p -DDE BRN 1914064, see Di-fl-butyl phthalate BRN 1914072, see p,p -DDD BRN 1915474, see Chlordane BRN 1915994, see Di-fl-octyl phthalate BRN 2049930, see Naled BRN 2051258, see Pindone BRN 2052046, see 2,6-Dinitrotoluene BRN 2054389, see 4,6-Dinitro-o-cresol BRN 2055620, see 2,4,5-T BRN 2057367, see Methoxychlor BRN 2059093, see Parathion BRN 2062204, see Benzyl butyl phthalate BRN 2215168, see Diuron BRN 2542580, see EPN BRN 2807677, see 2-Acetylaminofluorene BRN 3195880, see a-BHC BRN 3196099, see Camphor BRN 3910347, see cis-Chlordane, frans-Chlordane Brocide, see 1,2-Dichloroethane Brodan, see Chlorpyrifos Bromchlophos, see Naled Bromex, see Naled Bromic ether, see Ethyl bromide Bromobenzol, see bromobenzene 4-Bromobiphenyl ether, see 4-Bromophenyl phenyl ether 4-Bromodiphenyl ether, see 4-Bromophenyl phenyl ether p-Bromodiphenyl ether, see 4-Bromophenyl phenyl ether Bromoethane, see Ethyl bromide Bromofluoroform, see Bromotrifluoromethane Bromofume, see Ethylene dibromide Brom-o-gaz, see Methyl bromide Bromomethane, see Methyl bromide Bromomethyl chloride, see Bromochloromethane... 

Cecolene, see Trichloroethylene Cekiuron, see Diuron Cekubaryl, see Carbaryl Cekusan, see Dichlorvos Celanex, see Lindane Celfume, see Methyl bromide Cellon, see 1,1,2,2-Tetrachloroethane Cellosolve, see 2-Ethoxyethanol Cellosolve acetate, see 2-Ethoxyethyl acetate Cellosolve solvent, see 2-Ethoxyethanol Celluflex DOP, see Di-rr-octyl phthalate Celluflex DPB, see Di-rr-butyl phthalate Celluflex TPP, see Triphenyl phosphate Celluphos 4, see Tributyl phosphate Celmide, see Ethylene dibromide Celthion, see Malathion... 

CP 1309, see Pentachlorophenol CPD-244, see 2-Nittopropane CPD-926, see Dibenzofuran 4-CPPE, see 4-Chlorophenyl phenyl ether p-CPPE, see 4-Chlorophenyl phenyl ether Crag sevin, see Carbaryl Crawhaspol, see Trichloroethylene 2-Cresol, see 2-Methylphenol 4-Cresol, see 4-Methylphenol oCresol, see 2-Methylphenol p-Cresol, see 4-Methylphenol Crestoxo, see Toxaphene Crestoxo 90, see Toxaphene oCresylic acid, see 2-Methylphenol p-Cresylic acid, see 4-Methylphenol oCresyl phosphate, see Tri-ocresyl phosphate Crisalin, see Trifluralin Crisalina, see Trifluralin Crisfuran, see Carbofuran Crisulfan, see a-Endosulfan, p-Endosulfan Crisuron, see Diuron Crolean, see Acrolein Crop rider, see 2,4-D Crotenaldehyde, see Crotonaldehyde Crotilin, see 2,4-D Crotonal, see Crotonaldehyde Crotonic aldehyde, see Crotonaldehyde CRS, see Phenol Crunch, see Carbaryl Cryptogil OL, see Pentachlorophenol CS, see oChlorobenzylidenemalononitrile, Methyl mercaptan... 

Methyl ferf-butvl ether. Thiram Carbon monoxide, see Acetaldehyde. Atrazine. Bromacil. Dalapon-sodium. Dieldrin, 1.4-Dioxane, Diuron, Formaldehyde, Formic acid, Malathion, Maleic anhydride. Methanol, Methyl chloride. Methylene chloride. Methyl iodide, 2-Methylpropene, fV-Nitrosodimethylamine, Oxalic acid, Phorate, Picloram, 2,4,5-T, TCDD, Tolnene, Triflnralin... 

Dichloropropylene, frans-1,3-Dichloropropylene, Dieldrin, Diuron, Epichlorohydrin, Formaldehyde, Hexachlorocyclopentadiene, Eindane, Methoxychlor, Methyl chloride. Methylene chloride, Pentachlorophenol, 2,4,5-T, 1,1,2,2-Tetrachloroethane, Toxaphene, 1,1,1-Trichloroethane, 1,1,2-Trichloroethane, 1,2,3-Trichloropropane, Trichloroethylene, 1.1.1-Trichloro-2.2.2-trifluoroethane. Trichlorofluoromethane, Vinyl chloride Hydrofluoric acid, see Trichlorofluoromethane, 1.1.1-Trichloro-2.2.2-trifluoroethane. Trifluralin Hydrogen, see Benzene, Chloroform, Difenzoquat methyl sulfate. 1,4-Dioxane, Ethylamine, Ethylbenzene, Ethylenimine, Formaldehyde. Formic acid, Hexachlorobenzene, Methyl bromide. Pentachlorobenzene. TCDD. Tetrachloroethylene. 

Trichlorobenzene. Trichloroethylene Hydrogen azide, see Alachlor. Aldicarb. Atrazine Hydrogen bromide, see Ethylene dibromide Hydrogen chloride, see Atrazine. Captan. Carbon tetrachloride. Chloroform. Chlorpropham. Chlorpyrifos. 1.2-Dichloroethane. Diuron. Endrin. Formaldehyde. Heptachlor. Heptachlor epoxide. Hexachlorocyclopentadiene. Linuron. Methyl chloride. Methylene chloride. Methyl formate. Monuron. Propanil. Tetrachloroethylene. Trichloroethylene. Vinyl chloride Hydrogen cyanide, see Acetontrile. Alachlor. Aldicarb. 

Broad range of herbicides and insecticides (atrazine, bromacil, carbofuran, 2-4- D, DDT, diuron, malathion, methyl parathion, simazine)... 

Urea herbicides. Phenyl urea chemistry represents one of the earliest classes of herbicides. Replacement of the aromatic chlorines of diuron with a trifluoro-methyl group resulted in improved crop selectivity. Fluometuron (Cotoran ) and parafluron are both selective urea herbicides, fluometuron developed for the control of grass and broadleaf weeds in cotton. It was prepared from the corresponding 3-trifluoromethyl anilines. A number of other phenyl urea herbicides were introduced later, including trimefluor, 3-chloro-4-trifluoromethoxyphenyl-A/,A/-dimethyl urea [19]. 

Dimethylamine chlordimefoim, chloromethiuron, chloroxuron, chlorotoluron, crimidine, dichlofluanid, dicrotophos, difenoxuron, dimefuron, dimethirimol, diphenamid, diuron, fenothiocarb, fenuron, ferbam, fluometuron, hexazinone, isoproturon, karbutilate, metoxuron, metribuzin, monuron, nicosulfuron, oxamyl, pirimicarb, pyrithiobac, thiram, tolyfluanid, triazamate, ziram 4 Dimethyl amino aniline fenaminosulf 2 Dimethyl amino 1,3 dichloro propane bensultap, thiocyclam N-N -Dimethylamino dimethyl aluminum nicosulfuron 2 Dimethyl amino 1,3 Dithiobenzyl propane thiocyclam 4 Dimethyl amino 3 methyl phenol aminocarb... 

An overview of the results illustrates some other surprising features. For diuron, N-methyl saccharin, coumarin, 3,4-dichloroaniline (probably) and 4-nitrotoleune, plot intercepts less than the anticipated L/aDorg were found, which should be the lowest allowed value for the plot intercept. These are largely high log Pow compounds. In this case, the calculation C = Ci er - PowCouter is particularly important. The flux was very small, and it is possible that true steady state fluxes were not established [32]. 

In some cases, degradation products may be produced as a result of attack on both the aromatic ring and aliphatic components of the compound. This is the case for diuron where hydroxylated photoproducts 1 and 2 (Scheme 4) are produced by reaction of HO with the aromatic ring (Process A) to form an adduct similar to that described above with subsequent loss of a chlorine atom [15]. The more important degradation pathway in this instance is via hydroxyl radical attack on the methyl of the dimethylurea group (Process B). 

Due to the thermal lability of the urea group, phenylureas are not amenable to GC-MS. They are frequently analysed by LC-MS. The general stmcture is shown below. The phenyl ring is substituted with halogen(s), methoxy, methyl, trifluoromethyl, or 2-propyl substitution. The Rj side chains are methyl groups for most phenylureas, while the Rj side chain can be methyl like in diuron, methoxy like in linuron, butyl like in neburon, or a proton like in monomethylmetoxuron. 

FIGURE 25.11 GC with a fused-silica capillary column and a NPD detector of some urea herbicides after conversion to their methylated forms. Symbol explanation A, monuron B, isoproturon C, chlorotoluron D, linuron E, diuron F, methabenzthiazuron G, tebuthiuron. (From Scott, S., Analyst, 118, 1117, 1993. With permission.)... 

When the solubilities of the methoxy methylureas (C-6313, linuron, and metobromuron) and the dimethylureas (diuron, fluometuron, and monuron) were considered separately, the values increased greatly (Table X). A plot of log aqueous solubilities vs. the percent adsorption or desorption showed that the two groups of chemicals fell into two different patterns (Figure 13). Substituting a methoxy group for a methyl... 

The triazines, such as simazine (4.62), are the most used of all soil-applied herbicides small changes in the substituents give excellent control over selectivity and persistence. These substances [and the phenylureas, such as diuron (4.63), which are also soil-types] act by interfering with the Hill reaction in photosynthesis (see Section 4.6). Both of these parent substances, simazine and diuron, have undergone extensive modification for particular purposes, but each is still extensively used. A newcomer, chlorsulfuron (6.73), combines molecular features from both parents, but is notable for the greater dilution at which it acts, and also for the speed (all cell division is halted within 1 hour). This substance, l-(2-chlorophenylsulfonyl)-3-(4-methoxy-6-methyl-l, 3,5-tri-azin-2-yl)urea, is taken up by wheat, oats, and barley plants which rapidly inactivate it. It is harmless to Man (Campion and Tichon, 1981). 

Atrazine, diuron, picric acid and the benzylamino derivative I react rapidly, and the thiolate salt III slowly, with both wild type and mutant thylakoids, whilst the N-methyl anilino compound II reacts slowly with the wild type and rapidly with the mutant. 

Phenoxy acids (2,4-dichlorophenoxy acetic acid, MCPA, and 2,4,5-trichlorophenoxy acetic acid) and similar acid herbicides (benzaton, dicamba, dichlorprop, and mecoprop) sulfonurea herbicides (chlorsulforon, metsulforon methyl, tribenuron methyl, and thifensulfuron methyl) triazine herbicides (methoxy-s-triazines, chloro-s-triazines, alkylthio-s-triazines) phenylurea herbicides (fenuron, monolinuron, and diuron), metabolites of the fungicide thiophanate-methyl (carbenazim and 2-aminobenzimidazole)... 

---