JPH0341466B2 - - Google Patents

Description

[Detailed Description of the Invention] Formula (In the formula, R ¹ represents a lower alkyl group, lower alkenyl group, or phenyl group, R ² represents a lower alkyl group, and X represents a halogen atom, a lower alkyl group, a lower alkoxy group, a nitro group, a cyano group, or a trifluoro Represents a methyl group. n is 0 or 1
Indicates an integer from 3 to 3, and when n is 2 or 3, X
may be the same or different from each other. ), salts thereof, and organic acid esters thereof are useful as herbicides and are described in JP-A-50-126830.

In addition, as a method for producing this 4-benzoylpyrazole derivative, the formula (In the formula, R ¹ , R ² , X and n are the same as above)
A method for carrying out a rearrangement reaction of a 5-benzoyloxypyrazole derivative having
No. 52-265, respectively, but the yield is about 80% or less.

The present inventors conducted research on a method for more efficiently carrying out the rearrangement reaction from a 5-benzoyloxypyrazole derivative () to a 4-benzoylpyrazole derivative ().

Organic synthesis reactions using fluorine-containing salts as catalysts have recently attracted attention, taking advantage of the fact that fluorine atoms form hydrogen bonds with hydrogen atoms in the substrate, increasing the nucleophilicity of the substrate and promoting the reaction. has been done. For example, the Journal of Chemical Society (J.Chem.Soc.Chem.
COmm.) 1978, 466, it was reported that alkylation, sulfenylation, and Michael addition reactions can be promoted by using a basic ion exchange resin coated with tetraalkylammonium fluoride or potassium fluoride as a catalyst. It has been reported. Furthermore, Chemistry Letters (Chem.Lett.) 45, 1979 and the same magazine, 755,
In 1979, it was reported that alkylation reactions were promoted by using various solid supports coated with potassium fluoride as catalysts. However, there are no known examples of using the above catalysts in benzoyl group rearrangement reactions such as Fries rearrangement.

The production method of the present invention comprises rearranging the 5-benzoyloxypyrazole derivative () to
- It has been found that when producing a benzoylpyrazole derivative (), the desired product can be produced in a high yield of 90% or more using a method of reacting in the presence of a fluorine-containing salt.

The fluorine-containing salt used in this reaction is:
For example, inorganic salts with alkali metals or ammonium such as potassium fluoride, sodium fluoride, ammonium fluoride, cesium fluoride and ammonium fluoride, organic salts with ammonium such as tetraethylammonium fluoride and tetrabutylammonium fluoride. Examples include salts, but potassium fluoride is particularly preferred for this reaction.

As the fluorine salt, in addition to ordinary synthetic powders, spray freeze-dried products such as spray-dried potassium fluoride can also be used. The best method is to use a solid carrier coated with a fluorine-containing salt as a catalyst. The solid carrier used is not particularly limited as long as it is a porous material with a large surface area that does not have catalytic activity in itself in order to utilize the catalytically active component more effectively. Alumina, silica gel, silica-alumina, celite, montmolinite, molecular sieve, etc. are used. Further, the size of the particles is not limited, but fine particles are preferable.
The amount of carrier may be at least the amount that can be coated with the fluorine-containing salt. To obtain a solid support coated with a fluorine-containing salt,
It is obtained by adding a solid carrier to an aqueous solution of a salt containing fluorine, leaving it to stand, and then dehydrating and drying it.

The amount of the catalyst used in the reaction is at least the equivalent molar amount of the fluorine-containing salt relative to the starting material, preferably 1.5 to 5.0 times the molar amount.

In carrying out the method of the invention, the reaction is carried out in the presence of a solvent. The solvent used is not particularly limited, such as polar or non-polar solvents as long as they do not participate in this reaction, and examples include halogenated hydrocarbons such as dichloromethane, dichloroethane, tetrachloroethane, chloroform, and carbon tetrachloride; benzene, Aromatic hydrocarbons such as toluene and xylene; Aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; C _3-5 alcohols such as isopropanol, tert-butanol and tert-amyl alcohol; Ethyl ether , dioxane, diisopropyl ether, and tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; nitrites such as acetonitrile and propionitrile; and mixed solvents of these solvents. Preferred solvents are aromatic hydrocarbon solvents, especially toluene, and _C3-5 alcohol solvents, especially tert-butanol, but the fact that good results can be obtained even with toluene is of great industrial merit.

The reaction temperature is not particularly limited, and the reaction is usually carried out at room temperature to about 150°C.

The time required for the reaction is 1 to 20 hours, depending on the type of solvent used and the reaction temperature.
After the reaction is completed, the target compound is collected from the reaction mixture by a conventional method. For example, by distilling off the solvent from the reaction mixture after completion of the reaction, the desired compound can be obtained as a salt. Since the carrier used is obtained as a mixture, by adding water to the mixture, the target compound is dissolved and separated from the carrier. The target compound can be isolated in a free state by usually adjusting the pH of the aqueous solution to 4 or less by adding an acid. This product can be further purified by conventional methods such as recrystallization to obtain a pure product.

Next, the method of the present invention will be explained in more detail with reference to Examples and Reference Examples, but the present invention is not limited thereto.

Example 1 4-(2,4-dichlorobenzoyl)-1,3-
Dimethyl-5-hydroxypyrazole 5-(2,4-dichlorobenzoyloxy)-
1.1g of 1,3-dimethylpyrazole to 10% of toluene
1.7 g of potassium fluoride-alumina catalyst (see Reference Example 1) was added thereto, and the mixture was heated at 100 to 110° C. for 6 hours with stirring. After cooling, the insoluble matter was removed, washed with water, and the washed water was adjusted to pH 3 with diluted hydrochloric acid to precipitate crystals. This was collected by filtration to obtain 1.01 g of the target compound with a mp of 165-166°C.
(Yield 91.8%) Example 2 4-(2,4-dichlorobenzoyl)-1,3-
Dimethyl-5-hydroxypyrazole 5-(2,4-dichlorobenzoyloxy)-
6 ml of tert-butanol and 1.12 g of potassium fluoride-celite catalyst (see Reference Example 2) were added to 1.1 g of 1,3-dimethylpyrazole, and the mixture was heated under reflux for 5 hours with stirring. After cooling, the solvent was distilled off under reduced pressure.
After washing the residue with benzene, water was added to the residue to remove insoluble matter. The aqueous solution was made acidic (PH3) with dilute hydrochloric acid and extracted with dichloromethane.
After drying the extract over anhydrous sodium sulfate, the solvent was distilled off to obtain 0.99 g of the target compound. (Yield: 90.0%) Example 3 4-(2,4-dichlorobenzoyl)-1,3-
Dimethyl-5-hydroxypyrazole 5-(2,4-dichlorobenzoyloxy)-
7 ml of tert-butanol and 1.16 g of potassium fluoride powder were added to 1.425 g of 1,3-dimethylpyrazole, and the mixture was heated under reflux for 3.5 hours with stirring, and then the solvent was distilled off under reduced pressure. Water was added to the residue, made alkaline with dilute aqueous sodium hydroxide solution, and washed with benzene. Aqueous solution is acidic with dilute hydrochloric acid (PH4-3)
and extracted with chloroform. After drying the extract over anhydrous sodium sulfate, the solvent was distilled off to obtain 1.32 g of the target compound. (Yield: 92.6%) The benzene cleaning agent was dried over anhydrous sodium sulfate, and the solvent was distilled off to recover 0.04 g (2.8%) of the starting material.

Example 4 Spray lyophilized potassium fluoride powder 1.16 instead of potassium fluoride powder in Example 3
The same procedure was carried out using 1.35 g of the target compound. (Yield 95.5%) Reference Example 1 Potassium fluoride-alumina (2:3) catalyst 20 g of potassium fluoride was dissolved in 400 ml of distilled water, 30 g of neutral alumina was added thereto, and after stirring at room temperature for several hours,
Water was distilled off under reduced pressure in a water bath temperature of 50-60°C. The residue was dried in a desiccator to obtain 53.5 g of the desired catalyst.

Reference Example 2 Potassium fluoride-Celite (2:3) catalyst From 4 g of potassium fluoride, prepare the desired catalyst according to Reference Example 1.
9.89g was obtained.

Claims (1)

[Claims] 1 formula A rearrangement reaction is performed on a 5-benzoyloxypyrazole derivative having the formula A method for producing a 4-benzoylpyrazole derivative, characterized in that the reaction is carried out in the presence of a fluorine-containing salt. In the above formula, R ¹ represents a lower alkyl group, lower alkenyl group, or phenyl group, R ² represents a lower alkyl group, and X represents a halogen atom, a lower alkyl group, a lower alkoxy group, a nitro group, a cyano group, or a trifluoro group. Indicates a methyl group. n is 0 or 1
represents an integer from 3 to 3, and when n is 2 or 3, X may be the same or different from each other. 2. The manufacturing method according to claim 1, wherein the fluorine-containing salt is a salt with an alkali metal or ammonium. 3. The manufacturing method according to claim 2, wherein the fluorine-containing salt is potassium fluoride. 4. The manufacturing method according to claim 3, wherein the fluorine-containing salt is a solid carrier coated with potassium fluoride. 5. The production method according to claim 3, wherein the reaction is carried out in an aromatic hydrocarbon solvent or a C _3-5 alcohol solvent. 6. The manufacturing method according to claim 1, wherein the 4-benzoylpyrazole derivative of formula () is 1,3-dimethyl-4-(2,4-dichlorobenzoyl)-5-hydroxypyrazole.