KR890000420B1 - Preparation process for 4-benzoylpyrazol derivatives - Google Patents

Abstract

4-Benzoylpyrazol derivs. of formula (II) are prepd. by the transition-reaction of 5-benzoyl oxypyrazol derivs. of formula (I) in the presence of a base contg. Al. In the formulars, R1 is lower alkyl, lower alkenyl or phenyl; R2 is lower alkyl; X is halogen, lower alkyl, lower alkoxy, nitro, cyano, or trifluoromethyl 3 n is 0,1 or 3; when n is 2 or 3, x is equal or not. (II) and their salts and their organic acid ester are useful for herbicides.

Description

Preparation of 4-benzoylpyrazole derivatives

[expression]

Wherein R ¹ represents a paying alkyl group, a lower alkenyl group or a 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 methyl group. Is a 0 or an integer of 1 to 3, and when n is 2 or 3, X may be the same or different from each other.) 4-benzoylpyrazole derivatives, salts thereof and organic acid esters thereof are useful as herbicides. It is described in Unexamined-Japanese-Patent No. 50-126830. Moreover, as a manufacturing method of this 4-benzoylpyrazole derivative

[expression]

A method of subjecting a 5-benzoyl oxypyrazole derivative having R ¹ , R ² , X and n to be the same as the former, with a basic alkali metal salt or basic alkali in the presence of a metal salt or in the presence of aluminum chloride is carried out in Japan. It is known from Japanese Patent Laid-Open Nos. 52-266 and 52-265, respectively, and the yield is about 80% or less.

The present inventors have studied a method for more efficiently carrying out the potential reaction from 5-benzoyl oxypyrazole derivative (I) to 4-benzoylpyrazole derivative (II). In order to form a hydrogen bond with a hydrogen atom of the substrate, an organic synthesis reaction using a fluorine-containing salt has recently been attracting attention because the nucleophilicity of the substrate is increased and the reaction is accelerated. For example, the Journal of Chemical Society Society Cable. Communications (J. Chem. Soc. Chem. Comm) 1978, 466 used basic ion exchange resins coated with tetraalkyl ammonium, fluoride or potassium fluoride as catalysts to provide alkylation, sulfenylation and Mikel addition reactions. Acceleration has been reported. In addition, Chem. Lett. 45 (1979) and Co. 755 (1979) report that the alkylation reaction is promoted by catalyzing various solid carriers coated with potassium fluoride. However, the example which used this catalyst for the potential reaction of benzoyl groups, such as a fleece potential, is still unknown.

The preparation method of the present invention is a method of reacting the 5-benzoyl oxypyrazole derivative (I) with an electric reaction in the presence of a fluorine-containing salt to produce the 4-benzoyl pyrazole derivative (II) in a high yield of 90% or more. It was found that the target product was prepared. Fluorine-containing salts used in this reaction include, for example, inorganic metals with alkali metals or ammonium, such as potassium fluoride, sodium fluoride, ammonium fluoride, cesium fluoride and ammonium fluoride, tetraethylammonium fluoride and tetrabutylammonium fluorine. Organic salts with ammonium, such as a lide, are mentioned, but potassium fluoride is particularly preferable for this reaction.

In addition to the usual synthetic powders, the salts of fluorine are spray freeze-dried products such as spray dry and potassium fluoride. In addition, the method of using a solid carrier coated with a fluorine-containing salt as a catalyst is the best method. The solid carrier to be used is not particularly limited as long as it is a porous material having a large surface area that does not have a catalytic action in order to utilize the catalytically active component more effectively. For example, alumina, silica gel, silica alumina, which are usually used as a carrier of a solid catalyst. , Celite, montmorite, and molybculive are used. In addition, the size of the particles is not limited, but finer particles are better. The amount of the carrier may be more than the amount that can be coated with a salt containing electric fluorine. In order to obtain a solid carrier coated with a fluorine-containing salt, the solid carrier is added to an aqueous solution of a fluorine-containing salt, and then left to dehydrate and dried.

The amount of the catalyst used for the reaction is a salt containing fluorine with respect to the starting material, more than sugar moles, and preferably 1.5 to 5.0 times mole. In carrying out the process of the invention the reaction is carried out in the presence of a solvent. The solvent to be used is not particularly limited as long as it is not involved in the present reaction. Examples thereof include halogenated hydrocarbons such as dichloromethane, dichloroethane, tetrachloroethane, chloroform and carbon tetrachloride; Aromatic hydrocarbons such as benzene, toluene and xylene; Aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; C _3-5 alcohols, such as isopropanol, tert- butanol, and tert- amyl alcohol; Ethers such as ethyl ether, dioxane, diisopropyl ether and tetrahydrofuran; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Mixed solvents of these solvents such as nitriles such as acetonitrile and propionitrile. Preferably, the solvent is an aromatic hydrocarbon solvent, in particular toluene, a C _3-5 alcohol solvent, particularly tert-butanol, and it is a great industrial feature that the effect of using toluene is obtained.

There is no restriction | limiting in particular in reaction temperature, Usually, reaction is performed at room temperature to about 150 degreeC. The time required for the reaction is 1 to 20 hours and is determined by the type of solvent used and the reaction temperature. After completion of the reaction, the target compound is collected from the reaction mixture by a conventional method. For example, it is obtained as a salt of the target compound by distilling a solvent from the reaction mixture after completion | finish of reaction. Since the used carrier is obtained as a mixture, the target compound is dissolved and separated from the carrier by adding water to these mixtures. The said aqueous solution can isolate an objective compound in a glass state by adjusting acid to 4 or less normally by adding an acid. It can also be refine | purified by a commercial method, such as a recrystallization method, and the pure article can be obtained.

Next, the method of the present invention will be described 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

1.1 g of 5- (2,4-dichlorobenzoyloxy) -1,3-dimethylpyrazole was dissolved in 10 ml of toluene, and 1.7 g of potassium fluoride-alumina catalyst (see Reference Example 1) was added thereto and stirred at 100 to 110 ° C. Warmed for 6 hours. After cooling, the insolubles were filtered off, the insolubles were washed with water, and the washed water was adjusted to pH 3 with dilute hydrochloric acid to precipitate crystals. This was filtered off to obtain 1.01 g of the target compound at mp.165 to 166 ° C. (Yield 91.8%).

Example 2

4- (2,4-dichlorobenzoyl) -1,3-dimethyl-5-hydroxypyrazole

1.1 g of 5- (2,4-dichlorobenzoyloxy) -1,3-dimethylpyrazole was added to 6 ml of tert-butanol and 1.12 g of potassium fluoride-celite catalyst (see Reference Example 2), followed by heating to reflux for 5 hours with stirring. . After cooling, the solvent was distilled off under reduced pressure, and the residue was washed with benzene, and water was added to the residue to remove insoluble matters. The aqueous solution of the filtrate was made acidic with pH (pH 3) and extracted with dichloromethane. The extract was dried over anhydrous sodium sulfate and 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

To 1.425 g of 5- (2,4-dichlorobenzoyloxy) -1,3-dimethylpyrazole, 7 ml of tert-butanol and 1.16 g of potassium fluoride powder were added, heated to reflux for 3.5 hours with stirring, and the solvent was distilled off under reduced pressure. Water was added to the residue, made alkaline with an aqueous solution of dilute sodium hydroxide and washed with benzene. The aqueous solution was made acidic (pH 4-3) with dilute hydrochloric acid and extracted with chloroform. The extract was dried over anhydrous sodium sulfate and the solvent was distilled off to obtain 1.32 g of the target compound (yield: 92.6%).

The benzene washing solution 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

In Example 3, instead of the potassium fluoride powder, 1.16 g of spray-freeze-dried potassium fluoride powder was used in the same manner to obtain 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, stirred for several hours at room temperature, and water was distilled off under reduced pressure in a water bath temperature of 50 to 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 9 g of potassium fluoride, 9.89 g of the target catalyst were obtained according to Reference Example 1.

Claims (6)

A process for producing the 4-benzoylpyrazole derivative of the following formula (II), wherein the 5-benzoyl oxypyrazole derivative of the formula (I) is subjected to a potential reaction in the presence of salt containing fluorine.

In the above formula, R ¹ represents a lower alkyl group, a lower alkenyl group or a phenyl group, R ² represents a lower alkyl key, and X represents a halogen atom, a lower alkyl group, a lower alkoxy group, a nitro group, a cyano group or a triple luoromethyl group. n represents 0 or an integer of 1 to 3, and when n is 2 or 3, X may be the same or different from each other. The process for producing 4-benzoylpyrazole derivatives according to claim 1, wherein the salt containing fluorine is a salt with an alkali metal or ammonium. The process for producing 4-benzoylpyrazole derivatives according to claim 2, wherein the salt containing fluorine is potassium fluoride. The process for preparing 4-benzoylpyrazole derivatives according to claim 3, wherein the salt containing fluorine is a solid carrier coated with potassium fluoride. The process for preparing 4-benzoylpyrazole derivatives according to claim 3, which is reacted in an aromatic hydrocarbon solvent or a C _3-5 alcohol solvent. The process for preparing 4-benzoylpyrazole derivatives according to claim 1, wherein the 4-benzoylpyrazole derivative of formula (II) is 1,3-dimethyl-4- (2,4-dichlorobenzoyl) -5-hydroxypyrazole.