JPS6118766A - Preparation of pyrazole derivative - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a herbicide for paddy fields in high yield without preparing by-products, by reacting 4-(2,4-dichlorobenzoyl)-1- methyl-5-chloropyrazole with a benzyl alcohol. CONSTITUTION:A compound shown by the formula I is chlorinated with a chlorinating agent such as phosphorus oxychloride, thionyl chloride, etc. to give 4-(2,4- dichlorobenzoyl)-1-methyl-5-chloropyrazole shown by the formula II, which is reacted with a compound shown by the formula III (R is H, or lower alkyl; X is halogenm nitro, or alkyl; n is 0-3) in an organic solvent in the presence of a basic substance to give a pyrazole derivative shown by the formula IV.

Description

[Detailed description of the invention] This invention r! , general formula ([): (In the formula, R is a hydrogen atom or a lower alkyl group.

X represents a halogen atom, a nitro group or a lower alkyl group, and D represents O or an integer of 1 to 5.

When n is 2 or 3, they may be the same or different. ) The present invention relates to a novel method for producing a pyrazole derivative represented by:

A pyrazole derivative represented by the general formula (I) (hereinafter referred to as 1)
This compound is called this compound. ) is a compound useful as an active ingredient of a selective herbicide, 4G-, and a herbicide for paddy fields. (% Kaisho 5
(See Japanese Patent Publication No. 8-185568) Conventionally, as a method for producing the two compounds, a method according to the 9-order reaction formula is known.

(In the formula, R, , as a result.

(L/L) A compound represented by the following formula (K) is produced as a by-product OH.

The subsequent purification process becomes complicated, and this method cannot be said to be industrially advantageous.

The present inventors investigated various methods for producing this compound (VL), and found that no by-products shown in the formula were produced.
How can this compound be produced in high yield? Heading 9 The present invention has been completed.

Oh.

With the compound represented by.

General formula (■): In formula C, R is a hydrogen atom or a lower alkyl group.

X represents a halogen atom, a nitro group or a lower alkyl group, and 0 represents 0 or an integer of ri1 to 3.

When n is 2 or 5, X may be the same or different. ) in an organic solvent in the presence of a basic substance (wherein R, X and n represent the same meanings as above). This invention relates to a method for producing a derivative.

Examples of the lower alkyl group for R in formulas (1) and (lit) include methyl group, ethyl group, propyl group, tertiary-butyl group, etc., and examples include chlorine atom, bromine atom, and fluorine atom. Examples of the a) J atom include lower alkyl groups such as methyl group, ethyl M+ n-propyl group, 1so-globyl group, n-butyl group, and tert-butyl group.

Methanol is used as a solvent for the reaction.

Excluding some alcohols such as ethanol.

Common solvents can be used. For example, benzene.

Aromatic hydrocarbons such as toluene and xylene, ethers such as diethyl ether, tetrahydrofuran, dioxa/, diglyme, and acetate.

Ketones such as methyl ethyl lactone, esters such as ethyl acetate, halogenated carbonates such as dichloromethane and chloroform, hydrogen, and acetonitrile.

Dimethyl sulfoxide, N,N-dimethylformamide, hequinamethylphosphoric triazide and the like can be mentioned. These may be used alone or in combination, or may be used in combination with water. The basic substance to be used is not particularly limited; for example, potassium hydroxide, sodium hydroxide, potassium carbonate,
carbonic acid), inorganic salts such as IJium, triethyl aban,
Abanes such as N,N-dimethylaniline, pyridines, metallic sodium, sodium hydride, turntables
Potassium butoxy, sodium tertiary butoxy and the like can be mentioned.

For reaction wet hair, the range from room temperature to the boiling point of the solvent used is usually desirable. The time required for the reaction is 9 usually 1
The reaction is completed in about 50 hours.

This ratio of moles of raw materials used can be calculated using the above formula ([
) 1 compound of formula (III) per mol of compound
The preferred range is about 9.0 to 10 moles, more preferably 1.0 to 2.
A range of about 0 mol is desirable.

In addition, the formula of the raw material (the old compound is phosphorus oxychloride.

It can be easily obtained according to the 9th order reaction formula using a chlorine supplement such as thionyl chloride.

(TV) (TI) Next, the method of the present invention will be specifically described with reference to Examples. However, the present invention is not limited to these only.

Example 1 Synthesis of 4-(2,4-dichlorobenzoyl)-1-methyl-5-benzyloxypyrazole 0.8 f ([102 mol)] of sodium hydroxide.

Add to 10 g of acetonitrile and keep at 60℃,
4-(2,4-dichlorobenzoyl)-1-methyl-5
A 101 nt solution of acetonitrile containing chlorpyrazole L 45f (0,005 mol) and benzyl alcohol 0.59 P (Q, OO 55 mol) was added dropwise over 30 minutes with stirring.Then, the reaction temperature was kept at 60°C. .

Stirred for 6 hours. After cooling, the generated salt eF was separated, and the solvent was distilled off under reduced pressure. The resulting residue was dissolved in 30 g of benzene, washed successively with a saturated aqueous sodium bicarbonate solution and saturated brine, and dried over anhydrous sodium sulfate. , by distilling off all the solvent.

The target compound 1.642 was obtained.

Example 2 4-(2,4-dichlorobenzoyl)-1-
Synthesis of methyl-5-benzyloxypyrazole Benzyl alcohol [N of L65F ([1006 mol)]
, 0.14 F (0006 mol) of sodium hydride was added to a 10-solution of N-dimethylformamide, and the solution that became homogeneous after hydrogen generation was mixed with 4-(2,4-dichlorobenzoyl)-1-methyl. -5-ri0 rubirazole j, 45
f ((1005 mol)) was added dropwise to a 10H1 solution of N,N-dimethylformamide at 40°C over a period of 50 minutes.The trowel was stirred for 50 minutes to complete the reaction. Distilled away.

Thereafter, the same treatment as in Example 1 was carried out to obtain the target compound 1.71 f gold.

Example 3 4-(2,4-dichlorobenzoyl)-1-
Synthesis of methyl-5-benzyloxi-7virazole 0.67 f (fl, 006 mol) of potassium tert-butoxide was added to dry tetrahydro-7/10-;
Furthermore, benzyl alcohol α65F ((1,OO6
mol) was added dropwise to room temperature to make a homogeneous solution i, 4-(2
, 4-dichlorobenzoyl)-1-methyl-5-chloropyrazole (α005 mol) in a dry tetrahydro 7 run jOmt solution at 30° C. for 10 minutes with stirring. Thereafter, the reaction was completed by stirring at room temperature for 50 minutes, and the resulting salt was separated, and the solvent was distilled off under reduced pressure. Thereafter, the same post-treatment as in Example 1 was performed to obtain the target compound 1.67 f f<.

Example 4 4-(2,4-dichlorobenzoyl)-1-
Synthesis of mef-5-(2-chlorobenzyloxy)-pyrazole 4-(2,4-dichlorobenzoyl)-1-methyl-5 in 10 rnl of dried
-Chlorpyrazole 1.459 (0,005 mol l
and 0-chlorobenzyl alcohol α71y (o,
Dissolve o o s mol) and hydrogenate at room temperature
IJum (0,005 mol) was added slowly.

Furthermore, after stirring at room temperature for 1 hour, the solvent was removed under reduced pressure. After distilling off, the same treatment as in Example 1 was carried out to obtain the target compound 1.8.
I got f.

Example 5 a -(2,4-dichlorobenzoyl)-
Synthesis Example 4 of 1-methyl-5-(1-,yenethyl-7)-pyrazole (!CO-chlorobenzylalco-/
+/f, 1-7 enethyl alcohol (J-61f(
The desired product 1,62 was obtained using the same treatment as in Example 4, except that α005 mol) K and sodium hydride were replaced with all-metal sodium a14F.

Claims (1)

[Claims] A compound represented by the following formula (II): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) and General formula (III): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III ) (wherein, R represents a hydrogen atom or a lower alkyl group, X represents a halogen atom, a nitro group, or a lower alkyl group, and n
represents 0 or an integer from 1 to 3. When n is 2 or 3, X may be the same or different. ) General formula (I) characterized by reacting with a compound represented by A method for producing a pyrazole derivative represented by .).