Preemergence herbicides

Amino-2-bromoimidazoles (77) have been prepared by the action of hydrogen bromide on a-cyanoalkylcyanamides (74) and were found to display preemergent herbicide activity (64JOC153). These 4-aminoimidazoles (77) are unstable in the presence of water and undergo rapid decomposition on treatment with base. 

Used industrially as an insecticide, molluscicide, and preemergence herbicide. 

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... 

DCPA 450-1350 Phthalate preemergence herbicide Low Birds Fish... 

N-sec-butyl-4-tert-butyl-2,6-dinitroaniline org chem C14H21N3O4 Orange crystals with a melting point of 60-6rC solubility in water is 1.0 part per million at 24°C used as a preemergence herbicide. en sek bytid al for tart byud al tu siks, dT,nT-tro an-a,len ... 

Metolachlor Chloroacetanilide 51218-45-2 3.32 1976 Herbicide A preemergence herbicide used to control certain broad-leaf and annual grassy weeds in a variety of situations... 

A preemergence herbicide used for general weed control including grasses and broad-leaved weeds in a range of crops Chemical transformation product. Parent simazine and atrazine Chemical transformation product. Parent atrazine... 

Several polymeric acyl-transfer reactants have been used to give am-ide/ester products in the solution phase. The excess polymer-bound acyl-transfer reactants and polymer-bound nucleofuge byproducts are easily removed after completion of the reactions. One such application involved the activated nitrophenyl esters 25 (reaction 8).40 A mixture of 10 acid chlorides was converted to an equimolar mixture of 10 amide products a potent preemergent herbicide was discovered using this parallel synthetic approach.41... 

In 1955 monuron was registered as the first preemergence herbicide in citrus (Day, 1955), followed by diuron and simazine. Simazine was recommended by the University of Florida as an excellent weed control tool for citrus beginning in 1962 (Kretchman and McCown, 1962). 

Singh, M. and D.P.H. Tucker (1983a). Preemergence herbicides for container grown citrus. HortScience 18 950-952. 

Singh, M. and N.H. Achhireddy (1984). Tolerance of citrus rootstocks to preemergence herbicides. J. Environ. Hort., 2 73-76. 

Singh, M., D.P.H. Tucker, and S.H. Futch (1990). Multiple applications of preemergence herbicide tank mixtures in young citrus groves. Proc. Fla. State Hort. Soc., 103 16-21. 

Triazine herbicides, principally simazine, have been an integral part of this change in management practice. Simazine is used alone and in combination with other preemergence herbicides for weed control in the plant row. It has low water solubility, low volatility, long residual activity, and gives a broad spectrum of annual weed control. 

---