Benzylidene pyrazolones, production and use thereof

Details Benzylidene pyrazolones, production and use thereof Benzylidene pyrazolones, production and use thereof

2000-05-11

2001-08-07

Ramsuer, Robert W. (Department: 1626)

Plant protecting and regulating compositions

Plant growth regulating compositions

Organic active compound containing

C544S140000, C544S182000, C544S216000, C544S238000, C544S333000, C544S405000, C546S211000, C546S276100, C548S204000, C548S236000, C548S240000, C548S247000, C548S265800, C548S312400, C548S364100, C548S365100, C548S365700, C548S366100

Reexamination Certificate

active

06271179

ABSTRACT:

The present invention relates to benzylidenepyrazolones of the formula I
where the substituents and the index n have the following meanings:
R
1
is unsubstituted or substituted C
1
-C
6
-alkyl;
R
2
is unsubstituted or substituted C
1
-C
6
-alkyl, unsubstituted or substituted C
1
-C
6
-alkoxy, halogen, nitro, cyano;
R
3
is hydrogen, halogen, nitro, cyano, a group NR
5
R
6
, OCOR
5
, NR
5
COR
6
, CO
2
R
5
, —COSR
5
, —CONR
5
R
6
, C
1
-C
4
-alkoxyiminoalkyl, C
1
-C
6
-alkylcarbonyl, unsubstituted or substituted C
1
-C
6
-alkyl, unsubstituted or substituted C
1
-C
6
-alkoxy, unsubstituted or substituted C
1
-C
6
-alkylthio, unsubstituted or substituted C
2
-C
6
-alkenyl, unsubstituted or substituted C
2
-C
6
-alkynyl, unsubstituted or substituted phenyl, unsubstituted or substituted phenoxy, an unsubstituted or substituted 5- or 6-membered saturated or unsaturated heterocycle which may contain up to 4 nitrogen atoms and/or up to 2 oxygen or sulfur atoms as ring members;
R
4
is C
1
-C
6
-alkyl, C
1
-C
4
-haloalkyl;
or
R
3
and R
4
form an optionally substituted saturated or unsaturated 2- or 3-membered bridge which may contain a sulfur atom which may be oxidized to give sulfoxide or sulfone;
R
5
is hydrogen or unsubstituted or substituted C
1
-C
6
-alkyl;
R
6
is unsubstituted or substituted C
1
-C
6
-alkyl;
R
7
is hydrogen, C
1
-C
6
-alkyl or C
1
-C
4
-haloalkyl;
n is 0, 1 or 2;
x is hydrogen, chlorine or bromine;
where the compounds claimed may be present both in the trans and in the cis form or as a mixture of these isomers.
Furthermore, the present invention relates to compositions which comprise the compounds of the formula I, and to the use of the compounds I and of compositions comprising them for controlling harmful plants, to novel benzoylpyrazoles of the formula II and to a process for preparing the compounds I and II.
Herbicidally active 4-benzoylpyrazoles are disclosed in the literature, for example in EP-A 282 944 or WO 96/26206. However, 4-benzoyl-5-chloropyrazoles have hitherto not been described. In EP-A 282 944, it is only mentioned in a general way that the reaction of 4-benzoyl-5-hydroxypyrazoles with acyl halides should lead to 4-benzoyl-5-chloropyrazoles.
Benzylidenepyrazolones, some of which have herbicidal activity, are disclosed in U.S. Pat. No. 4,382,948 and JP 61268670. All the structures of the prior art have a very specific substitution pattern in the phenyl moiety of the benzylidenepyrazolone: in the position para to the methyne bridge, for example, there is in each case a hydrogen or halogen atom or a trifluoromethyl or nitro group.
However, the herbicidal properties of the prior art compounds and their compatibility with crop plants are not entirely satisfactory.
It is an object of the present invention to provide novel, in particular herbicidally active, compounds having improved properties.
We have found that this object is achieved by the benzylidenepyrazolones of the formula I according to the invention and by their herbicidal activity.
The present invention also provides stereoisomers of the compounds of the formula I. Both pure stereoisomers and mixtures thereof are included.
The compounds of the formula I may be present as cis or trans isomers and may contain, depending on the substitution pattern, one or more chiral centers, in which case they may also be present as mixtures of enantiomers or diastereomers. The invention provides both the pure isomers, enantiomers or diastereomers and mixtures thereof.
Benzylidenepyrazolones of the formula I and benzoylpyrazoles of the formula II according to the invention can be prepared as described below.
Benzylidenepyrazolones of the formula Ia (X=hydrogen) can be synthesized by Knoevenagel condensation of pyrazolones of the formula III, in which the radicals R
1
and R
7
are as defined above, and a substituted benzaldehyde of the formula IV, in which the radicals R
2
to R
4
are as defined above, similarly to the method described in U.S. Pat. No. 4,382,948.
Furthermore, the compounds Ia are obtainable for example by reductive dehalogenation from compounds of the formula I in which X is bromine.
Benzylidenepyrazolones Ib (X=bromine or chlorine) can be prepared from the compounds Ia described above by halogenation with bromine or chlorine and subsequent dehydrohalogenation in the presence of base.
The benzylidenepyrazolones Ib are preferably obtained from ketones of the formula V, which are either known or which can be prepared similarly to known compounds (see DE-A 19709118.0 and WO 96/26200), by reaction with acyl halides.
Suitable acyl halides are, for example, the halides of sulfuric acid, carbonic acid and phosphoric acid. For the exchange with chlorine, preference is given to using thionyl chloride, phosgene, phosphorus pentachloride and particularly preferably phosphorus oxychloride. For the exchange with bromine, preference is given to using phosphorus oxybromide.
The reaction can be carried out in a customary manner, with or without solvent or with a solvent which is inert under the reaction conditions. Generally, it is possible to control the selectivity of the reaction by addition of a base of low nucleophilicity such as, for example, pyridine, dimethylaminopyridine or dimethylformamide.
The reaction temperature is generally from 0° C. to 200° C., preferably from 50° C. to 140° C.
In this reaction, a mixture of both isomers with respect to the newly formed double bond may be obtained. In this case, the isomers can be separated, if required (for example by crystallization, extraction or chromatography).
A byproduct of this reaction are the compounds II which, depending on the substitution pattern and the way in which the reaction is carried out, may be obtained in smaller, similar or higher proportions. Many of these compounds are novel, and they are of considerable interest as precursors for herbicidally active compounds (see for example EP-A 282 944).
The organic moieties mentioned for the substituents R
1
-R
7
or as radicals on phenyl rings or heterocycles represent collective terms for lists of the individual group members. All hydrocarbon chains, ie. all alkyl, haloalkyl, cycloalkyl, alkoxy, haloalkoxy, alkylcarbonyl, alkenyl, alkynyl moieties may be straight-chain or branched. Unless stated otherwise, halogenated substituents preferably carry one to five identical or different halogen atoms. Halogen is in each case fluorine, chlorine, bromine or iodine.
Examples of other meanings are:
C
1
-C
4
-alkyl and the alkyl moieties of other radicals such as, for example, C
1
-C
4
-alkoxy, C
1
-C
4
-alkylcarbonyl, C
1
-C
4
-alkylthio: methyl, ethyl, n-propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl and 1,1-dimethylethyl;
C
1
-C
6
-alkyl and the alkyl moieties of other radicals such as, for example, C
1
-C
6
-alkoxy, C
1
-C
6
-alkylcarbonyl, C
1
-C
6
-alkylthio: C
1
-C
4
-alkyl as mentioned above, and pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1-ethyl-1-methylpropyl and 1-ethy-1-3-methylpropyl;
C
1
-C
4
-haloalkyl: a C
1
-C
4
-alkyl radical as mentioned above which is partially or fully substituted by fluorine, chlorine, bromine and/or iodine, ie. for example chloromethyl, dichloromethyl, trichloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl, chlorofluoromethyl, dichlorofluoromethyl, chlorodifluoromethyl, 2-fluoroethyl, 2-chloroethyl, 2-bromoethyl, 2-iodoethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 2-chloro-2-fluoroethyl, 2-chloro-2,2-difluoroethyl, 2,2-dichloro-2-fluoroethyl, 2,2,2-trichloroethyl, pentafluoroethyl, 2-fluoropropyl, 3-fluoropropyl, 2,2-difluoropropyl, 2,3-difluoropropyl, 2-chloropropyl, 3-chloropropyl, 2,3-dichloropropyl, 2-bromopropyl, 3-bromopropyl, 3,3,3-trifluoropropyl, 3,3,3-trichloropropyl, 2,2,3,3,3-pentafluorop

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