Claims
- 1. A compound of the formula ##STR11## where X is ethyl.
- 2. A process for combating unwanted grasses among crop plants, wherein the grasses or the soil in which the crops are planted is treated with an effective amount of a 5-aryl-cyclohexane-1,3-dione derivative of the formula ##STR12## where X is ethyl.
- 3. A process as defined in claim 2, wherein a per-emergence application of the 5-aryl-cyclohexane-1,3-dione derivative is applied to the soil in which the crops are planted.
- 4. A process as defined in claim 2, wherein the crop plants are broadleaved plant.
- 5. A process as defined in claim 2, wherein the crop plants are wheat or barley.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 3047924 |
Dec 1980 |
DEX |
|
Parent Case Info
This application is a continuation of Ser. No. 732,899, filed May 9, 1985 which is a continuation of Ser. No. 329,125, filed Dec. 9, 1981, both now abandoned.
The present invention relates to novel 5-arylcyclohexane-1,3-dione derivatives and to herbicides containing these compounds.
It is known that 5-aryl-cyclohexane-1,3-dione derivatives can be used for the selective control of undesirable grasses in broad-leaved crops (German Published Application DAS No. 2,439,104). It is also known that, in particular, p-substitution of the phenyl ring causes the active ingredient to be tolerated by the grassy crop plant wheat (Proc. 4th International Congress of Pesticide Chemistry (IUPAC), 1978, page 235). The best results have been achieved with compounds containing a p-methyl radical, such as 2-(1-ethoxyaminopropylidene)-5-(4-methylphenyl)-cyclohexane-1,3-dione. In the above publication, the observation that changing the alkoxyaminopropylidene radical to alkoxyaminobutylidene leads both to a drop in herbicidal activity and to a reduction in the toleration by crops is particularly noteworthy. In the example using wheat as the crop, only 5-aryl-cyclohexane-1,3-dione derivatives containing ethoxyaminopropylidene radicals are mentioned as active ingredients which cause little damage to wheat.
We have found that compounds of the general formula ##STR2## where X is fluorine, chlorine, ethyl or n-propyl, and the salts of these compounds, control undesirable grasses well in cereals, if X is ethyl, and are, surprisingly, better tolerated by wheat and barley than the known active ingredient, whilst if X is fluorine or chlorine, they still have a good herbicidal action on Alopercurus myosuroides and other undesirable grasses, with a certain reduction in action on Avena fatua, and are likewise surprisingly well tolerated by cereals.
The novel compounds can exist in several tautomeric forms: ##STR3##
All these forms are embraced by the claim.
The novel compounds can be prepared from the ketones of the general formula I, in accordance with the following equation: ##STR4## where X has the above meanings and Y is an anion, for example chloride, sulfate, nitrate or bromide.
The reaction is advantageously carried out in a heterogeneous phase system in an inert solvent at from 0 to 80.degree. C., or from 0.degree. to the boiling point of the mixture, in the presence of a base, for example ammonia or a carbonate, bicarbonate, acetate, alcoholate, hydroxide or oxide of an alkali metal or an alkaline earth metal, in particular of sodium, potassium, magnesium or calcium. Organic bases, such as pyridine or tertiary amines, can also be used.
A defined pH range which is particularly suitable for the reaction is that from pH 2 to pH 7, in particular from pH 4.5 to pH 5.5. This pH is advantageously established by adding acetates, for example alkali metal acetates, especially sodium acetate or potassium acetate, or their mixtures. The alkali metal acetates are use, for example, in amounts of from 0.5 to 2 moles per mole of the ammonium compound.
Suitable solvents are, for example, methanol, ethanol, isopropanol, benzene, tetrahydrofuran, chloroform, acetonitrile, dichloroethane, ethyl acetate, dioxane and dimethylsulfoxide.
The reaction takes some hours. The reaction produce can be isolated by concentrating the mixture, adding water and extracting the mixture with a nonpolar solvent, or by distilling off the solvent under reduced pressure.
The novel compounds can also be prepared by reacting the compounds I with ethoxyamine.
The compounds of the formula I can be obtained by acylating the substituted cyclohexane-1,3-diones II ##STR5## as described, for example, in Tetrahedron Lett. 29, 2491.
Compounds for the formula II can also exist in the following tautomeric form IIa ##STR6##
Compounds of the formula II can be obtained from the esters III or their salts by boiling with an alkali metal hydroxide solution and subsequent heating in an acid medium. ##STR7##
Compounds of the formula III can be prepared from benzaldehydes by methods which are known from the literature, for example by aldol condensation with acetone and subsequent cyclization with malonates, by a method similar to that in Organic Synthesis Coll. Vol. II, page 200. The compounds of the formula III are also obtained by reacting the aldehyde ##STR8## with malonic acid by the method of Knoevenagel-Doebner (of. Org. Reactions, Volume 15, page 204), esterifying the acid formed and cyclizing the product with an acetoacetate by a method similar to that described, for example, in Houben-Weyl, Methoden der Organischen Chemie, Volume 8, page 598.
Examples of salts of the compounds are the alkali metal salts, in particular the potassium and sodium salts.
The sodium and potassium salts of the novel compounds can be obtained by treating these compounds with sodium hydroxide or potassium hydroxide in aqueous solution or in an organic solvent, such as methanol, ethanol or acetone.
Sodium alcoholates and potassium alcoholates can also be used as the base.
Other metal salts, for example the manganese, copper, zinc, iron and barium salts, can be prepared from the sodium salt by reaction with the corresponding metal chlorides in aqueous solution.
The Examples which follow illustrate the preparation of the novel cyclohexane-1,3-diones.
US Referenced Citations (1)
| Number |
Name |
Date |
Kind |
|
3950420 |
Sawaki et al. |
Apr 1976 |
|
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 2439104 |
Mar 1975 |
DEX |
Non-Patent Literature Citations (3)
| Entry |
| Chem. Abstracts, vol. 85, Nr. 5281g (1976); |
| Chem. Abstracts, vol. 86, Nr. 16357h (1977). |
| Proc. 4th International Congress of Pesticide Chemistry (IUPAC), 1978, p. 235. |
Continuations (2)
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Number |
Date |
Country |
| Parent |
732899 |
May 1985 |
|
| Parent |
329125 |
Dec 1981 |
|
Patent Grant
4844735
