KR810000815B1 - Preparing process for 4-benzoyl pyrazol derivatives and its aluminum salts - Google Patents

Abstract

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Description

Preparation of 4-benzoylpyrazole derivatives and aluminum salts thereof

The present invention relates to a method for producing pyrazole derivatives disclosed in Japanese Patent Application Laid-Open No. 50-126830, and more particularly to a method for producing 4-benzoylpyrazole derivatives of the following general formula (I) and aluminum thereof.

Wherein R ₁ represents a lower alkyl group or a lower alkenyl group,

R ₂ represents a lower alkoxy group, X represents a halogen atom or a lower alkyl group, n represents an integer of 1 to 3, and when n is 2 or 3, they may be the same or different from each other, provided that R ₁ and R ₂ are both methyl groups When Xn is 2-chloro or 4-nitro.

The compounds of the general formula (I) may exist as tautomers as indicated below.

Wherein R ₁ , R ₂ , X and n are as described above.

In the general formula (I), suitable as R ₁ is a straight or branched lower alkyl group having 1 to 3 carbon atoms such as methyl, ethyl, n-propyl or isopropyl, especially methyl or aryl, 2- Straight or branched lower alkenyl groups having 3 or 4 carbon atoms such as butenyl, 3-butenyl, 1-methyl-2-propenyl or 2-methyl-2-propenyl, in particular aryl, R ₂ Represents a straight or branched lower alkyl group, in particular a methyl group, having the same carbon number as exemplified for R ₁ , X represents a halogen atom such as chlorine, cancellation, oxo or fluorine, in particular a chlorine atom or methyl, ethyl, n A straight or branched lower alkyl group having 1 to 4 carbon atoms such as -propyl, isopropyl, n-butyl or tert-butyl. Particularly suitable compounds are compounds wherein R ₁ is a methyl group or an aryl group, R ₂ is a methyl group and Xn is 2,4-dichloro.

The compound of the general formula (I) obtained by the method of the present invention and aluminum thereof are useful as an herbicide or an intermediate of herbicide synthesis.

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

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

2. 1,3-dimethyl-4- (2-bromobenzoyl) -5-hydroxypyrazole, m.p. 154 to 156 ° C

3. 1,3-dimethyl-4- (2-methylbenzoyl) -5-hydroxypyrazole, m.p. 82 to 83 ° C

4. 1,3-dimethyl-4- (2-fluorobenzoyl) -5-hydroxypyrazole, m.p. 158 to 159 ° C

5. 1-ethyl-3-methyl-4- (2,4-dichlorobenzoyl) -5-hydroxypyrazole, m.p. 176 to 177 ° C

6. 1,3-dimethyl-4- (4-tert-butylbenzoyl) -5-hydroxypyrazole, m.p. 172 to 173 ° C

7. 1,3-dimethyl-4- (3,4-dimethylbenzoyl) -5-hydroxypyrazole, m.p. 197-198 ° C.

8. 1,3-dimethyl-4- (2-iodobenzoyl) -5-hydroxypyrazole, m.p. 171 to 172 ° C

9. 1,3-aryl-3-methyl-4- (2,4-dichlorobenzoyl) -5-hydroxypyrazole, m.p. 191 to 163 ° C

10. 1,3-dimethyl-4- (2,5-dichlorobenzoyl) -5-hydroxypyrazole, m.p. 183 to 184 ° C

11. 1,3-dimethyl-4- (3,5-dimethylbenzoyl) -5-hydroxypyrazole, m.p. 165 to 167 ° C

12. 1,3-dimethyl-4- (4-methylbenzoyl) -5-hydroxypyrazole, m.p. 114 to 116 ° C

13. 1-methyl-3-n-propyl-4- (2-chlorobenzoyl) -5-hydroxypyrazole, m.p. 125 to 126 ° C

14. 1,3-dimethyl-4- (2,4,5-trichlorobenzoyl) -5-hydroxypyrazole, m.p. 156 to 157 ° C

15. 1,3-dimethyl-4- (2,4-dimethylbenzoyl) -5-hydroxypyrazole, m.p. 95-96 ° C

According to the method of the present invention, the compound of the general formula (I) and the aluminum salt thereof are subjected to a potential reaction of the pyrazole derivative of the following formula (II) in the presence of about 1.2 moles or more of aluminum chloride with respect to 1 mole of the derivative. It can be obtained by.

Wherein R ₁ , R ₂ , X and n are as described above.

As a method for preparing these known compounds which are analogous to the pyrazole derivatives of the general formula (I), quicklime or 1,3-dimethylpyrazolone under heating in dioxane, pyridinedimethylformamide or benzene suspended with triethylamine A method of benzoylating the 4-position of 1,3-dimethylpyrazolone by reacting benzoyl chloride has been proposed. Chemistry of This Cyclocyclic Compound, Vol. 8, 722, 1972 (Russian Origin, 779, 1972).

However, according to this conventional method, the method for producing the desired compound in the best yield, that is, the reaction in dioxane suspended in quicklime is also about 70 to 75%, and as a by-product 0-benzoyl 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 pyrazololone is difficult to proceed, and the yield of the compound of the general formula (I) is 50 % Or less, and a large amount of 2,4-dichlorobenzoic acid is liberated.

In addition, the potential reaction by zinc chloride of 1-phenyl-3-methyl-5-benzoyloxypyrazole, which is a similar compound of the compound represented by the general formula (II), has all been tested in the prior art, By-products of large amounts of coloring matter have been reported. [Yamta Chem. Scandinavica (Acta Chem. Scand.) 13 1668-1670 (1959).

As a result of precisely scanning the potential reaction of the pyrazole derivative having the general formula (II), the inventors have found that the potential reaction product fluctuates greatly depending on the type and amount of the catalyst to be added. In order to obtain a good yield of 4-benzoylpyrazole derivative having I), it was found that the use of about 1.2 moles or more of aluminum chloride is an important requirement for 1 mole of the compound of formula (II), and thus the present invention was completed. .

When the amount of aluminum chloride to be added is 1.5 mol or less with respect to 1 mol of the compound of the formula (II), the production of the target compound (I) of the present invention is considerably lowered and is hardly obtained at equimolar or less.

In carrying out the process of the invention, the reaction is easily carried out by reacting the compound of general formula (II) with a predetermined amount of aluminum chloride. The reaction is carried out in the presence or absence of a solvent, but in order to perform the reaction smoothly, a method using a solvent is preferable. The solvent used is not particularly limited unless it is involved in the present reaction. For example, dichloroethane, tetra Halogenated hydrocarbons, such as chloroethane and chloroform, Halogenated aromatic hydrocarbons, such as a monochlorobenzene, etc. are mentioned, Especially halogenated hydrocarbons are used suitably. The amount of aluminum chloride added as the potential catalyst is suitably used 1.2 mol or more, preferably 1.5 mol or more, particularly 1.5 to 2 mol, with respect to 1 mol of the compound of formula (II). It is advantageous that the upper limit is stopped at about three times the molar value as seen from the battery such as reaction operation and economical efficiency. The reaction temperature is not particularly limited and is suitably carried out at room temperature to about 150 ° C. The time required for the reaction is usually about 10 minutes to 5 hours.

After the reaction is completed, the target compound of the method of the present invention is taken out of the reaction mixture by a conventional method. For example, after completion, water is added to the reaction mixture and stirred to separate the organic layer, and then the solvent is removed from the solution to obtain the target compound as an aluminum salt. The obtained aluminum salt can be isolated by mixing with a strong acid (pH 1 or less) by mixing with a strong acid (I) in a glassy state. It can also be purified by commercial methods such as recrystallization to obtain its pure product.

In addition, the raw material compound (II) is easily produced by reacting 1,3-substituted pyrazolone and an acid chloride according to a known method, for example, the method described in JP-A-3776 / 1975 specification. .

Next, the method of the present invention will be described in more detail with reference to Examples.

Example 1

1,3-dimethyl-4- (4-chlorobenzoyl) -5-hydroxypyrazolealuminum salt

15.0 g of aluminum chloride is added to 25.1 g of 1,3-dimethyl-5- (4-chlorobenzoyloxy) pyrazole and stirred for 60 minutes while heating at about 120 ° C.

After the reaction was completed, 100 ml of benzene was gradually added to the reaction mixture, followed by cooling. Then, 100 ml of water was added thereto, followed by stirring. The solvent was distilled off from the organic layer under reduced pressure to obtain 23.6 g of the target compound. Yield 91%

Melting point 282-284 ° C (crystallized from benzene-n-hexane)

Elemental Analysis Value (%) C ₁₂ H ₁₀ N ₂ O ₂ ClAl / 3

Calculated: C, 55.72; H, 3. 90; N, 10.83; Cl, 13.71

Experimental Value: C, 55.24; H, 3.87; N, 10.58; Cl, 14.05

Example 2

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

Aluminum chloride 15.0 was added to 28.5 g of 1,3-dimethyl-5- (2,4-dichlorobenzoyloxy) pyrazole, and the mixture was heated and melted at 120 ° C., followed by stirring for 60 minutes. After completion of the reaction, 100 ml of dichloroethane was added dropwise to the reaction mixture, followed by cooling with addition of 880 ml of water, followed by stirring. The organic layer was separated, and the solvent was kept under reduced pressure from the organic layer to obtain 24 g of the target compound.

Yield 82%, Melting | fusing point about 155 degreeC.

Elemental Analysis Value (%) C ₁₂ H ₉ N ₂ O ₂ Cl ₂ A / 3

Calculated: 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

Example 3

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

28.5 g of 1,3-dimethyl-5- (2,4-dichlorobenzoyloxy) pyrazole and 20.0 g of aluminum chloride were mixed in 100 ml of dichloroethane and stirred at room temperature for 60 minutes, followed by concentrated hydrochloric acid (35%), 25 ml and 50 ml is added and it stirred for 60 minutes. After cooling, the water layer is removed from the reaction mixture and the solvent is distilled off under reduced pressure from the organic layer to give 22.8 g of crude crystal of the target compound. Yield 80%

Melting point 165-166 deg. C (recrystallized from methanol)

Elemental Analysis Value (%) C ₁₂ H ₁₀ Cl ₂ N ₂ O ₂

Calculated: C, 50.55; H, 3.54; N, 9.82; Cl, 24.87

Experimental Value: C, 50.21; H, 3. 48; N, 9.71; Cl, 24.54

Example 4

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

2.3 g of 1,3-dimethyl-5- (2-methylbenzoyloxy) pyrazole and 2.0 g of aluminum chloride are mixed in 10 ml of dichloroethane and heated and stirred for about 60 minutes. After cooling, 10 ml of water, 2.5 ml of concentrated hydrochloric acid (35%) and 20 ml of dichloroethane were added and heated to reflux for about 60 minutes. After cooling, the organic layer was separated from the reaction mixture and the solvent was distilled off under reduced pressure to yield 2.2 g of a reddish brown oily residue. Recrystallization of the residue with a small amount of methanolol yields the target compound as pale brown crystals having a melting point of 82 to 83 ° C.

Elemental Analysis Value (%) C ₁₃ H ₁₄ N ₂ O ₂

Calculated: C, 67.81; H, 6. 82; N, 12.17

Experimental Value: C, 67.70; H, 6.03; N, 12.26

Claims (1)

In preparing the compound of formula (I), the pyrazole derivative of formula (II) is subjected to a potential reaction in the presence of about 1.2 moles or more of aluminum chloride per mole of the derivative. 4-benzoylpyrazole derivatives thereof and a method for producing aluminum salts thereof.

Wherein R ₁ represents a lower alkyl group or a lower alkenyl group, R ₂ represents a lower alkyl group, X represents a halogen atom or a lower alkyl group, n represents an integer of 1 to 3, and n is 2 to 3. And X may be the same or different from each other, and Xn is not 2-chloro or 4-nitro when both R ₁ and R ₂ are methyl groups.