Herbicide phenyl carbamate

Dansylation has also been used to detect N-phenyl-carbamate and urea herbicides by adding excess reagent on the applied spot directly on the tic (3 2. This in situ reaction proved to be cleaner and more practical than labelling in solution and was applied to the detection of Linuron (33) in agricultural crops at the 0.05 ppm level. Other applications involving hydrolysis and dansylation in solution prior to tic have been reported with organophosphorus insecticides... 

Scheme 141 Preparation of the herbicide Linuron from chloiomethyl-N(4-chloro-phenyl) carbamate.

Two compounds of this group have been developed into commercial herbicides first phenmedipham, methyl (3-m-tolylcarbamoyloxy-phenyl)carbamate (15), and two years later desmedipham, ethyl (3-phenylcarbamoyloxy-phenyl)carbamaie... 

N,N-Dimethylureido)phenyl (N-methyl-N-phenyl)carbamate (SN 40624, 17) is a selective postemergence herbicide in cereals. At rates of 1-2 kg active ingredient/ha it is effective against Alopecurus, Apera, Lamium, Matricaria, Stellaria and Veronica species and annual grasses in the cotyledon first-leaf stage. 

Methoxycarbonylamino)phenyl (N-methyl-N-phenyl)carbamate (SN 40454, 18) is a broad-spectrum pre- and postemergence herbicide effective primarily against broad-leaved weeds. Used preemergence at a rate of 2-4 kg active ingredient/ha, it is selective in peanut, cotton and soybean. In postemergence application at a rate of l.S active ingredient/ha it is effective for directed spray treatment in cotton and soybean. 

A large-scale cyclization reaction of carbamates with functionalized butenoates, starting from carbamates prepared without phosgene, for the efEdent preparation of 3-(substituted phenyl)-5-isopropylidene-l,3-oxazolidine-2,4-dione derivatives (azaladones) having potent herbicidal adivity, has been described in a patent application [240]. By reacting an N-(substituted phenyl)carbamate 312 with a 2-hydroxy-3-alkenoic acid ester (for example, ethyl 2-hydroxy-3-methyl-3-butenoate) or a 3-alkoxy-2-hydroxyalkanoic add ester, at 210 °C for 15 h, azaladone 313 was formed in 71.5% yield. 

N-methyl carbamate Carbamate insectides Phenyl urea herbicides Phenyl urea herbicides Phenyl urea herbicides 30 pesticides, including atrazine, simazine, alachlor, molinate... 

Potential Uses of These Polymers. We have studied the phenyl isocyanate modification of poly(vinyl alcohol) as a model system. Many uses exist for carbamates as medicines, pesticides and herbicides (67,68). For example, ethyl carbamate has been used to treat leukemia and multiple myeloma. Ethyl carbamate has also been used as an antidote for central nervous system poisoning by strychnine. The tranquilizer Meprobamate is a carbamate derivitive. Numerous pesticides and herbicides, such as Sevin and Propham, are also carbamate derivatives. Propham is isopropyl N-phenylcarbamate which bears a strong resemblence to the polymers of Equation 21, and this compound is used as a preemergence herbicide. Numerous other close analogs could be cited also. We might note also that the N-phenyl carbamoyl unit bears... 

Danielson LL, Gentner WA. 1970. Effect of solvent composition on inactivation of several phenyl and thio carbamate herbicides in soil. Proceedings of the Northeastern Weed Control Conference 24 308-312. 

Isocyanates can be reacted with poly(vinyl alcohol) In homogeneous solutions In dlmethylsulf-oxlde to produce modified polymers that contain between 10 and 100 S of the hydroxyl groups replaced by the appropriate carbamate group. In this study, modified polymers were prepared using phenyl, 3-chlorophenyl and 4-chlorophenyl Isocyanates and these polymers bear a strong structural similarity to known carbamate herbicides. 

Of the oxime carbamates, the herbicidal action of one derivative. 0-(N-phenyl-carbamoyDpropanon oxime (proximpham. 11) meets practical requirements. 

Compounds of the group are pre- and postemergence herbicides, effective against mono- and dicotyledonous annual weeds. They seem promising in monocotyledon-ous crops such as barley, wheat, maize and beet. Examples of efficient compounds are 3-(N,N-dimethylureido)phenyl N-(4-chlorophenyl)carbamate... 

Methoxycarbonylamino)phenyl N-(3-methylbut-2-yl)carbamate (SN 45 311, 19) is also a pre- and postemergence herbicide having essentially the same selectivity as SN 40454. Its /, -value is 6.4. 

A number of developmental methodologies which are of interest in the herbicidal field have been examined for the formation of carbamates and related intermediates. Phosgene and phenol reacted in the presence of triphenylphosphine and a quaternary ammonium salt catalyst at 120-125°C over a total period of 10 hours gave phenyl chloroformate in 89% yield (ref.26). 

Pesticides N-nitrosated under 1m vitro and vivo conditions in the laboratory have included the fungicide ziram (zinc dimethyldithiocarbamate), the insecticides carbaryl (1-naphthyl methyl carbamate) and propoxur (o-isopropoxy phenyl methyl carbamate) and the herbicides benzthiazuron [N-(2-benzothiazolyl)-N -methylurea], simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] and atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine). 

Only the diisocyanates are of interest for urethane polymer manufacture and relatively few of these are employed commercially. The most important ones used in elastomer manufacture are the 2,4- and 2,6-toluene diisocyanates (TDl) 4,4 -diphenylmethane diisocyanates (MDI) and its aliphatic analogue 4,4 -dicyclohexylmethane diisocyanate (Hi2 MDI) 1,5-naphthalene diisocyanate (NDI) 1,6-hexamethylenediisocyanate (HDI) xylyene diisocyanate (XDI), isophorone diisocyanate (IPDI) and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (TMDI). Also manufactured commercially are various monoisocyanates, including methyl, /7-propyl, /7-butyl, cyclohexyl, phenyl, and 4-chloro- and 3,4-dichlorophenyl isocyanates which are used for substituted ureas and carbamates important as herbicides and crop protection agents. 

Anion Source for Palladium Catalysis. The reagent serves as a source of weakly coordinating anions in the palladium-catalyzed formation of mixed phenyl ureas, a known class of commercially available herbicides, using palladium(II) acetate, copper(II) toluenesulfonate, and 2,2 -dipyridyl as the catalyst system. Other studies have suggested that use of this reagent to form palladium salts may have useful applications in the reductive carbonylation of nitroaromatic compounds to give isocyanates via initial carbamate formation (eq 2). ... 

Phenyl ketoxime carbamates, which are useful as selective herbicides, were prepared by treating a phenyl ketoxime with either a base and a carbamoyl halide or phosgene and a substituted amine. Field tests demonstrating the efficacy of emulsions of 316 as pre- and post-emergence herbicides in the presence of Loium per-... 

In the 1960s various heterocycles, anilides, and phenyl compounds substituted with urea or carbamate were known to exhibit herbicidal activity by interfering with photosynthesis in plant cells. Draber and co-workers at Bayer AG (Leverkusen, Federal Republic of Germany) investigated a new series of... 

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