Properties herbicides

This paper describes the initial phase of research directed toward the discovery of compounds produced by soil microorganisms, primarily actinomycetes, having potential for development as herbicides. Our interests include both new compounds, as well as previously known ones having heretofore unrecognized herbicidal properties. 

Paraquat is a broad-spectrum contact weed killer and herbage desiccant that is used widely in agriculture and horticulture. Paraquat was originally formulated in 1882, but its herbicidal properties were not discovered until 1955. Since its introduction in the early 1960s, paraquat has been used extensively in about 130 countries, including the United Kingdom, Canada, and the United States, on a wide variety of agricultural crops (Fletcher 1974 Haley 1979 Kelly et al. 1979 Anonymous 1988). 

Some 3-substituted anhydro-5-hydroxy-l,2,3,4-oxatriazolium hydroxides (4), anhydro-5-thiolo-1,2,3,4-oxatriazolium hydroxides (5) and anhydro-5-amino-l,2,3,4-oxatriazolium hydroxides (6) possess pesticidal or herbicidal properties <79BRP2015878>. Anhydro-5-hydroxy-l,2,3,4-oxatria-zolium hydroxides (4) are moderately active but relatively long-acting hypotensive agents <82JMC1503>. 

Cantharidin is a toxin isolated from fish. Among its numerous biological activities, cantharidin exhibits insecticide and herbicide properties. Cantharidin and norcanthar-idin are inhibitors of serine and threonine phosphatases, which are important enzymes for the regulation of cell processes and cell proliferation. Mono- and difluoronor-... 

HAVIS, DALLYN, AND SWEET—HERBICIDAL PROPERTIES OF PETROLEUM HYDROCARBONS... 

Two aliphatic acids possess, for grasses, many of the growth-distortion and toxicity effects associated with the synthetic auxins on dicotyledonous plants. Trichloroacetic acid and 2,2-dichloropropionic acid (dalapon), as the sodium salts, have been called grass "hormones or auxins, although Wilkinson184 could find no growth stimulation at low concentrations, and described dalapon as an antiauxin from its interference with indole-3-acetic acid effects. The herbicidal properties of trichloroacetate do not depend on its protein-denaturing ability, and those of 2,2-dichloropropionic acid involve, at least indirectly, the synthesis of pantothenic acid. 

Two groups of sucrose derivatives of herbicidal acids have been reported. The herbicidal properties of the sucrose esters of (2,4-dichlorophenoxy)-acetic acid and other analogs differed somewhat from the salts of the free herbicide acids. This could be accounted for as being due to differences in solubility and penetration, since it is unlikely, by analogy to the fatty acid esters, that the sucrose esters would remain intact in the plant. 0 The second set of sucrose esters were water-soluble sirups, having surfactant properties, prepared from reaction products of hydroxyethyl ethers of sucrose or diglycidyl ethers of poly(oxyetbylene glycol) with (2,4,5-tri-chlorophenoxy) acetic acid or other herbicidal acids. 1... 

Benzothiadiazinone 236 (R = H) can be converted with BrCN to the 1-cyano derivative 236 (R = CN) which, along with a number of related compounds, has herbicidal properties (78GEP2656289). Furthermore, 236 (R = CH2C1), when stirred with sodium azide in DMF, is said to lead to 236 (R = CH2N3), a representive of another series of herbicides (78GEP2656290). The 2-oxides (m = 1) and 2,2-dioxides (m = 2) 237 (Z = O or S) have also been patented as herbicides (79USP4155746). 

Within a short time, the discovery of and screening for the herbicidal properties of dialkylamino-.v-triazincs led to selection of the most promising candidates for field development and eventual commercial use. 

Gysin, H. and E. Kntisli (1956). Chemistry and the herbicidal properties of triazine derivatives. Proc. British Weed Control Conf., 3(2) 615—623. 

Knusli, E. and H. Gysin (1960). Chemistry and herbicidal properties of triazine derivatives. Adv. Pest Cont. Res., 3 289-357. 

The preharvest drop of citrus fruit can be reduced or prevented with 2,4-dichlorophenoxyacetic acid, which delays development in the abscission zone of the fruit stem, thus allowing the fruit to remain on the tree longer. Because of 2,4-D s herbicidal properties, however, care must be taken in spraying to prevent the chemical from damaging other crops, as well as the target crop... 

Diphenyl ether herbicides. The diphenyl ether class of herbicides belongs to a broader area of herbicides known as protoporphyrinogen oxidase (Protox) herbicides [20,21], Diphenyl ether herbicides were initially introduced over four decades ago in the 1960s with the discovery of nitrofen by Rohm and Haas (now Dow AgroSciences) [22] and bifenox by Mobil [23], These early diphenyl ether herbicides did not attain a significant role in the control of weeds in commercial crops until the 1970s, with the introduction of the trifluoromethyl compounds oxyfluorfen [24] and acifluorfen-sodium [25], Replacement of the chlorine with a trifluoromethyl group resulted in a dramatic increase in the herbicidal properties of these compounds, in terms of both potency and the spectrum of weeds controlled. 

Hoerlein, G. 1994. Glufosinate (phosphinothricin) a natural amino acid with unexpected herbicidal properties. Rev. Environ.Contam. Toxicol. 138, 73-145... 

Pyrazine diquatemary salts of types 16lB1 and 17152 are known and also 6,7-dihydro derivatives of 16.152a The diquaternary salt (17) was originally formulated as the monohydrate of 18, but attempts to dehydrate 17 to 18 have not been successful.152 Dipyrido[l,2-a 2, l -c]pyrazinium dibromide (16) has herbicidal properties it is reduced in aqueous solution to a stable radical cation.183 The related pyrido[l,2-a]pyrazinium salts of type 19 have also been prepared.153,1B4a... 

Crowe AJ (1987) Organotin compounds in agriculture since 1980. Part I. Fungicidal, bactericidal and herbicidal properties. Appl Organomet Chem 1 143-155... 

A number of 1 /7-pyrido[2,3-c]-l,2,6-thiadiazin-4(3/7)-one 2,2-dioxides and 1 //-pyrido[4,3-c]-1,2,6-thiadiazin-4(3//)-one 2,2-dioxides, for example (403), display herbicidal properties <75USP392064i, 77USP4014888). Four 3-arylpyrido[3,4-e]-1,2,4-triazines (404a-c) and (252) have been studied as germination inhibitors <84Mi 717-03). 

Since the discovery of the herbicidal properties of the aryloxy-phenoxypropanoates, there have been many studies aimed at determining their mode of action. Fewer reports have been published regarding the mode of action of cyclohexanediones. Neither class of compounds interferes with photosynthesis, respiratory 02 uptake, protein biosynthesis, or nucleic acid biosynthesis (4-6). Several physiological processes are disrupted by both the cyclohexanediones and aryloxyphenoxypropanoates, namely growth and development, maintenance of membrane integrity, auxin induced growth, and lipid metabolism (4.5.7.8). In addition, the aryloxyphenoxypropanoates have been reported to depolarize membrane potentials (9.10). However, no specific target site had been identified for either class of compounds. 

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