Isoxazole derivatives and their use as herbicides

Details Isoxazole derivatives and their use as herbicides Isoxazole derivatives and their use as herbicides

2000-10-02

2001-07-03

Lambkin, Deborah C. (Department: 1626)

Plant protecting and regulating compositions

Plant growth regulating compositions

Organic active compound containing

C548S243000

Reexamination Certificate

active

06255251

ABSTRACT:

This is a continuation of International Application No. PCT/EP99/02223, filed Mar. 31, 1999, the contents of which are incorporated herein by reference.
The present invention relates to new, herbicidally effective isoxazole derivatives, to compositions comprising said compounds, and to the use thereof for controlling weeds, in particular in crops of cultivated plants or for inhibiting plant growth.
Isoxazole derivatives with a herbicidal effect are described for example in WO 97/43270. The active ingredients disclosed therein, however, cannot always satisfy requirements with regard to potency and spectrum of action. There is thus a need for active ingredients with improved herbicidal characteristics. It has now been found that isoxazole derivatives with a specific substitution pattern possess outstanding herbicidal characteristics.
Accordingly, the invention relates to compounds of formula I
wherein R
1
and R
2
are independently C
1
-C
8
alkyl.
The alkyl groups occurring in the definitions of the substituents may be straight-chain or branched and are typically methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl and the isomers pentyl, hexyl, heptyl and octyl groups.
A compound of formula 1, wherein R
1
and R
2
are methyl, is preferred.
Compounds of formula I are prepared in a manner similar to that with known processes. Such manufacturing processes are described for example in WO 97/43270.
The compounds of formula I or compositions containing them may be used according to this invention by all standard methods of application used in agriculture, including preemergence application, postemergence application and seed dressing, as well as by different methods and techniques such as controlled release. For controlled release, a solution of the herbicide is applied to mineral granular carriers or to polymerized granules (urea/formaldehyde) and then dried. A coating can then be additionally applied (coated granules) that allows the herbicide to be released at a controlled rate over a specific period of time.
The compounds of formula I may be used as herbicides in unmodified form, i.e. as obtained in the synthesis. Preferably they are processed in conventional manner with the auxiliary agents customarily employed in formulation technology, e.g. to emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granulates or microcapsules. Such formulations are described, for example, in WO 97/34485 on pages 9 to 13. As with the type of agents, the methods of application such as spraying, atomizing, dusting, wetting, scattering or pouring, are selected in accordance with the intended objectives and the prevailing circumstances.
The formulations, i.e. the agents, preparations, or compositions containing the compound of formula I or at least one compound of formula I and usually one or more than one liquid or solid formulation assistant, are prepared in known manner, e.g. by homogeneously mixing and/or grinding the herbicide with said formulation auxiliaries, typically solvents or solid carriers. Surface-active compounds (surfactants) may additionally be used for preparing the formulations. Examples of solvents and solid carriers are described in WO 97/34485 on page 6.
Depending on the herbicide of formula I to be formulated, suitable surface-active compounds are non-ionic, cationic and/or anionic surfactants and surfactant mixtures having good emulsifying, dispersing and wetting properties.
Examples of suitable anionic, non-ionic, and cationic surfactants are listed in WO 97/34485 on pages 7 and 8.
Also the surfactants customarily employed in the art of formulation and described, inter alia, in “Mc Cutcheon's Detergents and Emulsifiers Annual” MC Publishing Corp., Ridgewood N.J., 1981, Stache, H., “Tensid-Taschenbuch” (Handbook of Surfactants), Carl Hanser Verlag, MunichNienna, 1981, and M. and J. Ash, “Encyclopedia of Surfactants”, Vol I-III, Chemical Publishing Co., New York, 1980-81 are suitable for manufacture of the herbicides according to the invention.
The herbicidal compositions will as a rule contain from 0.1 to 99% by weight, preferably from 0.1 to 95% by weight, of herbicide, from 1 to 99.9% by weight, preferably from 5 to 99.8% by weight, of a solid or liquid adjuvant, and from 0 to 25% by weight, preferably from 0.1 to 25% by weight, of a surfactant. Whereas it is preferred to formulate commercial products as concentrates, the end user will normally use dilute formulations. The compositions may also contain further ingredients, such as: stabilisers, e.g. where appropriate epoxidized vegetable oils (epoxidized coconut oil, rapeseed oil, or soybean oil); antifoams, typically silicone oil; preservatives; viscosity regulators; binders; and tackifiers; as well as fertilizers or other chemical agents.
The compounds of formula I are usually applied with success to the plants or the locus thereof in concentrations of 0.001 to 4 kg/ha, especially 0.005 to 2 kg/ha. The concentration required to achieve the desired action can be determined by experimentation. It will depend on the type of action, the development stage of the cultivated plant and of the weed, as well as on the application (locus, time, method), and as a result of these variables can vary over a wide range.
The compounds of formula I have excellent herbicidal and growth inhibiting properties, which make them suitable for application in crops of cultivated plants, especially in cereals, cotton, soybeans, sugar beet, sugar cane, plantations, rape, maize, and rice, and for the non-selective control of weeds. Crops will also be understood as meaning those crops that have been made tolerant to herbicides or classes of herbicides by conventional breeding or genetic engineering methods. The weeds to be controlled may be monocot as well as dicot weeds, typically Stellaria, Nasturtium, Agrostis, Digitaria, Avena, Setaria, Sinapis, Lolium, Solanum, Echinochloa, Scirpus, Monochoria, Sagittaria, Bromus, Alopecurus, Sorghum halepense, Rottboellia, Cyperus, Abutilon, Sida, Xanthium, Amaranthus, Chenopodium, lpomoea, Chrysanthemum, Galium, Viola, and Veronica.
The invention is illustrated by the following non-limitative Examples.


REFERENCES:
patent: 5863865 (1999-01-01), Lee et al.
patent: 2056044 (1992-05-01), None
patent: 2101105 (1994-01-01), None
patent: 0487357 (1992-05-01), None
patent: 0580439 (1994-01-01), None
patent: WO97/43270 (1997-11-01), None

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