KR810000816B1 - Preparing process for 4-benzoyl pyrazol derivatives and its aluminum salts - Google Patents

Abstract

4-Benzoyl pyrazole derivs. (I; R1 = Me, Et, allyl; R2 = Me) and their Al salts were prepd. by reaction of pyrazolone derivs. (II; R1 = R2 = Me) with benzoic acids III or their reactive derivs. in the presence of AlCl3. I and their Al salts were herbicides (no data).

Description

Preparation of 4-benzoylpyrazole derivatives and aluminum salts thereof

The present invention relates to a method for producing 4-benzoylpyrazole derivatives known by Japanese Patent Application Laid-Open No. 50-126830, and more specifically, to a method for producing 4-benzoylpyrazole derivatives of the following general formula (I) and aluminum salts thereof. It is about.

In the above formula, R ₁ represents a lower alkyl group or a lower alkenyl group, and R ₂ represents a lower alkyl group.

In the general formula (I), suitable as R ₁ is a linear or branched linear alkyl group having 1 to 3 carbohydrates such as methyl, ethyl, n-propyl or isopropyl, or 1-methyl-2-prop Linear or branched, suitable alkyl groups having 3 or 4 carbon atoms such as phenyl or allyl. Suitable as R ₂ are a linear or branched, suitable alkyl group having 1 to 3 carbon atoms as exemplified for R ₁ .

Particularly suitable compounds in view of the biological activity of the compounds are 2,4-dichloro or 2-chloro-4-nitro, wherein R ₁ is a methyl or allyl group and R ₂ is a methyl group.

The compounds of the general formula (I) and aluminum salts thereof obtained by the process of the present invention are useful as preparations or intermediates of herbicide synthesis.

Particularly useful compounds in the general formula (I) are preferably those in which R ₁ represents a methyl group or an allyl group, and R ₂ represents 2,4-dichloro representing a methyl group.

Aluminum salts of the general formula (I) are equally useful.

The compounds of the general formula (I) obtained by the method of the present invention exist as tautomers as shown below, and all of these isomers are included within the scope of the target compounds according to the present invention.

Wherein R ₁ and R ₂ are the same as described above.

1,3-dimethyl-4- (2-chlorobenzoyl) -5-hydroxypyrazole and 1,3-dimethyl-4- (4-nitrobenzoyl)-in pyrazole derivatives having the general formula (I) 5-hydroxypyrazole is a known compound, and as a method for producing these known compounds, 1,3-dimethylpyrazolone is heated in dioxane, pyridine, dimethylformamide or benzene suspended with quicklime or triethylamine. A method of benzoylating the 4-position of 1,3-dimethylpyrazolone by reacting benzoyl chloride has been proposed. Heterocyclic Compound Chemistry, Vol. 8, p. 722, 1972 (Reaction Origin, 779, 1972).

However, according to this conventional method, the method of producing the desired compound in the best yield, that is, the method of reacting in dioxane suspended in quicklime is also about 70 to 75%, and as a by-product, 0-benzoyl body. Is to generate. In addition, when this conventional method is carried out using 2,4-dichlorobenzoic acid instead of benzoyl chloride, benzoylation at the 4-position of pyrazolone is difficult to proceed, and the yield of the compound of the general formula (I) is 50%. Below, a large amount of 2,4-dichlorobenzoic acid is liberated.

The present inventors have conducted various studies on the industrially advantageous method for producing 4-benzoylpyrazole derivatives. As a result, by using aluminum chloride as a catalyst for benzoylation at the 4-position of the pyrazolone ring, the formation of by-products is small and good. It is found that the target object (I) and its aluminum salt are advantageously obtained in yield, and the present invention has been completed based on this finding.

According to the method of the present invention, the compound having the general formula (I) and its aluminum salt can be produced as follows. That is, the desired compound (I) can be prepared by reacting a pyrazolone derivative of the general formula (II) below with a benzoic acid or its reactive derivative of the general formula (III) in the presence of aluminum chloride.

Wherein R ₁ and R ₂ have the same meaning as described above.

In carrying out the process of the invention, the reaction is easily carried out by contacting the compound of formula (II) with a compound having formula (III) in the presence of aluminum chloride, with or without a solvent. do. The solvent used is not particularly limited as long as it has a boiling point of 30 ° C. or higher and is not involved in the present reaction, and examples thereof include aromatic or aliphatic halogenated hydrocarbons such as monochlorobenzene, dichloroethane and tetrachloroethane. . In either case, the benzoylation at the 4-position of the pyrazolone derivative of the general formula (II) can be promoted by heating or heating the reaction system to 30 ° C. or higher, preferably 60 to 120 ° C. after the addition of the aluminum chloride condensate. have.

The amount of aluminum chloride used is equal to or more than one mole, preferably about 1.2 to 3 times mole, per 1 mole of the compounds of the formulas (II) and (III). In addition, the order of adding the compounds of the formulas (II) and (III) and the aluminum chloride catalyst is not particularly limited, and usually, by adding the aluminum chloride catalyst while mixing the compounds of the formulas (II) and (III) and heating the reaction, The desired compound (I) of the present invention and its aluminum salt are produced in good yield.

Examples of reactive derivatives of benzoic acid having the general formula (III) include acid chlorides, acyl halides such as acid bromide, acid anhydrides, and the like, but in general, the use of acid chlorides is preferable in view of its reactivity and economical efficiency.

The addition amount and reaction temperature of the aluminum chloride catalyst have a great influence on the production amount of the desired compound (I) and its aluminum salt. In general, the yield of the desired compound (I) and its aluminum salt is increased by increasing the amount of the aluminum chloride catalyst added. When the amount of the catalyst is large, for example, when 1.5 times mole or more is used for 1 mole of the compound of the formulas (II) and (III), even at a relatively low temperature, for example, a reaction temperature of 30 to 80 ° C, Compound (I) and its aluminum salts are produced in good yields.

On the other hand, when the reaction temperature is reacted at 80 ° C or higher, for example, 100 to 120 ° C or higher, it is possible to reduce the amount of the catalyst to some extent, for example, 1 for 1 mole of the compound of formulas (II) and (III). Even in the use of -1.5 times molar, the desired compound (I) and its aluminum salt are produced in good yield. These reaction conditions can be selected arbitrarily.

After completion of the reaction, the target compound of the method of the present invention is taken from the reaction mixture by a conventional method. For example, after completion of the reaction, the reaction mixture is washed with water and diluted alkaline aqueous solution, the organic layer is separated and dried, and the solvent is distilled off from the solution to obtain the aluminum salt of formula (I). Furthermore, after adding inorganic acids, such as concentrated hydrochloric acid, to water, and treating it similarly, an organic layer is isolate | separated, dried with a suitable drying body, and a solvent is distilled from a solution, and the compound of Formula (I) is obtained in a glass state. The target compound of preparation can be refine | purified by a conventional method, for example, a recrystallization method.

In addition, the raw material compound of Formula (II) is manufactured in accordance with the method described in Ferride (Ber.) 43.2106 (1910).

Representative compounds among the compounds having the general formula (I) obtained by the method of the present invention are described below. However, this invention is not limited by these illustrations.

1) 1,3-dimethyl-4- (2,4-dichlorobenzoyl) -5-hydroxypyrazole m.p. 165-166 ° C

2) 1-ethyl-3-methyl-4- (2,4-dichlorobenzoyl) -5 = hydroxypyrazole m.p. 176 ~ 177 ℃

3) 1-allyl-3-methyl-4- (2,4-dichlorobenzoyl) -5-hydroxypyrazole m.p. 161-163 ° C

Next, the method of the present invention will be described in more detail with reference to Examples. However, this invention is not limited by these Examples.

Example 1

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

(1) 11.2 g of 1,3-dimethyl-5-pyrazolone and 20.9 g of 2,4-dichlorobenzoyl chloride were mixed in 100 ml of tetrachloroethane, heated to reflux for 30 minutes, and then 20.1 g of aluminum chloride was added thereto at about 100 ° C. Heat reflux for 60 minutes again. After ice-cooling, 100 ml of water was added, the mixture was stirred, and the water layer was removed. Subsequently, the mixture was washed with 40 ml of 1N sodium hydroxide aqueous solution, and the organic layer was separated and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure, and the obtained solid residue was recrystallized with ligroin to give 24.7 g of the target compound having a melting point of about 155 占 폚. Yield 84.3%

Elemental Analysis Value (%): C ₁₂ H ₉ O ₂ Cl ₂ Al / ₃

Calc .: C, 49.17; H, 3.09; N, 9.55; Cl, 24.19

Found: C, 49.22; H, 3.30; N, 9.18; Cl, 23.13

(2) 11.2 g of 1,3-dimethyl-5-pyrazolone and 2.9 g of 2,4-dichlorobenzoyl chloride are mixed in 100 ml of dichloroethane, heated and refluxed for 30 minutes, and the solvent is distilled off under reduced pressure. Subsequently, 16.0 g of aluminum chloride is added and stirred at about 120 ° C. for 60 minutes (the stirring becomes difficult).

After completion of the reaction, the reaction mixture was cooled while gradually decreasing 100 ml of dichloroethane, and washed with 80 ml of water. The organic layer was separated, dried over anhydrous sodium sulfate, and the solvent was distilled off from the solution under reduced pressure to obtain 23.1 g of the target compound. Yield 79%

Example 2

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

11.2 g of 1,3-dimethyl-5-pyrazolone and 20.9 g of 2,4-dichlorobenzoyl chloride were mixed in 100 ml of dichloroethane, heated and refluxed for 60 minutes, and then the heating was stopped, and 20.1 g of aluminum chloride (anhydrous) was added. And reflux for 60 minutes (HCl is generated). After cooling, 100 ml of water was gradually lowered while stirring, and then, 25 ml of concentrated hydrochloric acid was added, followed by heating and stirring for 2 hours. After the completion of the reaction, the water layer was removed from the reaction mixture and the organic layer was concentrated to give 21.4 g of the target compound. Yield 75%

Elemental Analysis Value (%): C ₁₂ H ₁₁ N ₃ O ₆

Calculated: C, 50.55; H, 3.53; N, 9.82; Cl, 24.88

Experimental Value: C, 50.85; H, 3.54; N, 9.81; Cl, 24.55

Claims (1)

In the process for preparing the compound of the general formula (I), the pyrazolone derivative of the general formula (II) is reacted in the presence of aluminum chloride with benzoic acid or its reactive derivative of the general formula (III) 4-benzoylpyrazole of formula (I) is a method for producing a derivative.

In the above formula, R ₁ represents a lower alkyl group or a lower alkenyl group, and R ₂ represents a lower alkyl group.