JPH047340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 3-halopyrvaldehyde phenyl hydrazones are mainly useful as intermediate raw materials for agricultural chemicals such as insecticides and acaricides.

However, as a typical manufacturing method for this compound, 4
- A method is known in which a halogenoacetoacetic acid and a halogen-substituted phenyldiazonium salt are reacted in the presence of a base using water as a solvent.

However, during this reaction, intense carbon dioxide gas is generated and the formed crystals are blown up.As a countermeasure, lower alcohols such as methanol, ethanol, and propanol are used together, but even if such alcohols are used, Blowing up of the formed crystals cannot be completely suppressed, resulting in a decrease in yield, which is not necessarily satisfactory when implemented on an industrial scale.

However, the present inventors have conducted extensive research on a manufacturing method for solving the drawbacks of such conventional methods and industrially advantageously obtaining 3-halopyrvaldehyde phenyl hydrazones, and have found that halogenated hydrocarbons When 4-halogenoacetoacetic acid and halogen-substituted phenyldiazonium salt are reacted in the presence of a base in a mixed solvent of water and halogenated hydrocarbon, water, and alcohol, the above-mentioned drawbacks are not present and the desired product can be obtained. It was discovered that it could be obtained in good yield,
The present invention has now been completed.

That is, the manufacturing method of the present invention has the greatest feature in that a mixed solvent of a halogenated hydrocarbon and water or a mixed solvent of a halogenated hydrocarbon, water, and alcohol is used. By using such a specific solvent, it is possible to completely suppress the blowing up of carbon dioxide gas during the reaction, and since the crystals do not aggregate in a solvent system in which alcohol is further added, the precipitate obtained after the reaction is simply filtered out. In particular, it has the excellent advantage that the desired product can be obtained in good yield.

Furthermore, the use of such a mixed solvent has the following merits in terms of the preparation of 4-halogenoacetoacetic acid, which is the raw material for the above reaction. In other words, the 4-halogenoacetoacetic acid is obtained by reacting diketene with a halogen to form 4-halogenoacetoacetic acid chloride, which is then hydrolyzed. It can be used as a common solvent in the reactions of 4-halogenoacetoacetic acid, making it possible to omit the isolation of 4-halogenoacetoacetic acid, and furthermore, alcohol can be added afterward if necessary, which is an excellent industrial advantage.

The reaction steps of the present invention include () a step of obtaining 4-halogenoacetoacetic acid halide from diketene and a halogen; () a step of hydrolyzing 4-halogenoacetoacetic acid halide to obtain 4-halogenoacetoacetic acid;
() It consists of a step of reacting 4-halogenoacetoacetic acid with a halogen-substituted phenyldiazonium salt to obtain 3-halopyruvaldehyde phenylhydrazones, and is represented by the following general formula.

However, in the above formula, X and Y represent a halogen element, and X and Y may be the same or different. n is an integer from 1 to 5.

Hereinafter, the present invention will be explained step by step for each reaction.

The process in parentheses involves heating diketene and halogen at a temperature of -30
It is carried out at ~30°C, more preferably -10~10°C, with stirring in the presence of a solvent. The halogen is usually chlorine or bromine, but is not particularly limited. The halogen may be in a liquid state, a gaseous state, or a liquid state dissolved in an inert solvent, and is charged in a ratio of 1.00 to 1.05 moles of halogen per 1 mole of diketene. The halogenated hydrocarbon used in this step includes mono (or di, tri) chloromethane, carbon tetrachloride, mono (or di, tri) chloroethane, mono (or di, tri) chloropropane, etc., and is particularly preferred. Dichloromethane, trichloromethane (chloroform), carbon tetrachloride, and dichloroethane are used.

The step in parentheses performs hydrolysis. Specifically, water may be added all at once or gradually to the halogenated hydrocarbon solution containing 4-halogenoacetoacetic acid halide obtained in step (). Since 4-halogenoacetoacetic acid halide is easily decomposed, the reaction is usually carried out at a temperature of -30 to 30°C, preferably -10 to 10°C. The amount of water is not particularly limited as long as it is equal moles or more to 4-halogenoacetoacetic acid halide, and there is no problem even if water is present in an equal mole or more since water is used as a component of the solvent in the step (). but usually 1.0 to 1.1 (molar ratio)
It is appropriate to Hydrogen halide is produced as a by-product during the reaction, but it must be removed from the system as much as possible since it causes ineffective consumption of the base added in the step () described below. As the removal means, methods such as nitrogen gas blowing and reduced pressure removal are used.

The greatest advantage of the present invention is demonstrated in step (). That is, in step (), the 4-halogenoacetoacetic acid obtained through steps () and () is mixed in a mixed solvent of a halogenated hydrocarbon and water or in a mixed solvent of a halogenated hydrocarbon, water, and alcohol in the presence of a base. It is then reacted with a halogen-substituted phenyldiazonium salt. Of course, 4 obtained in step ()
- There is no particular need to isolate halogenoacetoacetic acid, and the halogenated hydrocarbon solution or halogenated hydrocarbon-water mixture of () can be used as is. The ratio of the halogenated hydrocarbon and water used as a solvent in step () is not particularly limited, but it is usually 0.005 to 1.0 mol, more preferably 0.01 to 0.2 mol of halogenated hydrocarbon per 1 mol of water. This reaction involves a decarboxylation reaction, but the solvent of the present invention can moderate the generation of carbon dioxide gas and the blowing up of target product crystals, which have been violent until now, to the extent that they are almost unnoticeable. Thus, by adding alcohol to a mixed solvent of halogenated hydrocarbon and water, the particle size of the produced crystals becomes appropriate, and the removal of the crystals from the reaction vessel and the transient properties can be greatly improved. The alcohols include lower alcohols such as methanol, ethanol, n-propanol, isopropanol, butanol, etc.
It is added in a molar ratio of 0.1 to 15.0, more preferably 0.7 to 8 molar. When carrying out the reaction, the solution containing 4-halogenoacetoacetic acid obtained in step () is added all at once or in portions or continuously under stirring to an aqueous solution or slurry in which the halogen-substituted phenyldiazonium salt is dissolved, and then alcohol is added. After adding , an aqueous solution containing a base is added dropwise little by little to allow the reaction to proceed. Of course, the preparation method,
The order is not limited to this, and 4-halogenoacetoacetic acid and a halogen-substituted phenyldiazonium salt are both prepared in a mixed solvent of a halogenated hydrocarbon and water, or a mixed solvent of a halogenated hydrocarbon, water, and alcohol. Any method can be adopted, such as a method in which an aqueous base solution is added dropwise, or a method in which water, or water and alcohol, and the diazonium salt are separately added to the solution containing 4-halogenoacetoacetic acid in step (), and then an aqueous base solution is added dropwise. The charging ratio of diazonium salt to 4-halogenoacetoacetic acid is generally 0.95 to 1.05 mol, but is not limited thereto. The reaction temperature is -30 to 30°C, preferably -5 to 5°C, the same as the reaction temperature during diazotization.

The halogen-substituted phenyldiazonium salt in the present invention is usually produced by the following method. That is,
For example, in the case of p-chlorophenyldiazonium chloride, p-chloroaniline is converted into a hydrochloride in a 2.5 to 3 times molar aqueous hydrochloric acid solution, and then -5 to 5
At a reaction temperature of .degree. C., an aqueous solution of p-chloroaniline and about the same molar amount of sodium nitrite is added dropwise to carry out diazotization to obtain the desired product. However, the present invention is not limited to the above method.

Examples of the halogen-substituted phenyldiazonium salt include o,m,p-chlorophenyldiazonium chloride, o,m,p-bromphenyldiazonium chloride, and the like. Bases include sodium acetate, potassium acetate, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and these two
A mixture of two or more species is used, but sodium acetate and sodium carbonate are usually preferably used.
The amount used is generally 1.5 to 5.0 mol per 1 mol of 4-halogenoacetoacetic acid.

The appropriate reaction time for step () is about 15 minutes to 3 hours, and after completion, the formed crystals are filtered and 3-halopyrvaldehyde phenyl hydrazones are obtained using known purification means such as washing with water. .

As mentioned above, the 3-halopyrvaldehyde phenylhydrazones thus obtained are very useful as agricultural chemicals, especially acaricides, and insecticide intermediates.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Using dichloroethane as a solvent, 0.5 mol of chlorine gas was blown into 0.5 mol of diketene over about 90 minutes at a temperature of -10°C to carry out a reaction to obtain 4-chloroacetoacetic acid chloride. The chloride-containing liquid 232.5
While keeping g at -10°C, add 9 g of water with stirring to perform hydrolysis, and further remove hydrogen chloride.
-Chloroacetoacetic acid was obtained. Separately, 0.48 mol of p-chloroaniline was dispersed in 92 g of water, and
Add 140 g of 35% by weight hydrochloric acid to make p-chloroaniline hydrochloride, and add 0.48 mol of sodium nitrite to water.
An aqueous solution of 48 g was charged over about 30 minutes while maintaining the temperature at -5 to 5°C to obtain p-chlorophenyldiazonium chloride. 474.5 g of a slurry containing 0.48 mol of p-chlorophenyldiazonium chloride was added to the 4-chloroacetoacetic acid solution, and then a saturated aqueous solution of 2 mol of sodium acetate was added dropwise over 1 hour while maintaining the reaction temperature at 0°C. . Although slight bubbles of carbon dioxide gas were observed during the dropwise addition, the reaction generally proceeded gently, and the formed crystals were not blown up by the carbon dioxide gas.

After completion of the dropwise addition, the mixture was stirred at room temperature for 2 hours, and the resulting colored crystals were filtered, thoroughly washed with water and methanol, and dried to obtain 110.9 g of 3-chloropyruvaldehyde (4-chlorophenyl) hydrazone. The structure of the compound was confirmed by NMR and IR, and the melting point was 190-192℃ (decomposition temperature), the yield was 95.0 mol% (based on p-chloroaniline, the same hereinafter), and the purity was
It was 95.0% by weight.

Comparative Example 1 The 4-chloroacetoacetic acid obtained in Example 1 was separately isolated and the same reaction was carried out using a mixed solvent of water and methanol as the solvent, but carbon dioxide gas was generated violently and the formed crystals were blown up. I was shocked.

In the end, due to the loss of 4-chloroacetoacetic acid in the isolation process and the loss in the reaction production process, the yield of 3-chloropyruvaldehyde (4-chlorophenyl) hydrazone was 86.0 mol%, and the purity was 93.0% by weight. significantly decreased compared to.

Examples 2 and 3 Experiments were conducted using chloroform (Example 2) and carbon tetrachloride (Example 3) as solvents instead of the dichloroethane used in Example 1, but the generation of carbon dioxide gas was mild and the crystals formed were There was no overflow at all.

The yield and purity were 94.5 mol%, 94.8% by weight (Example 2), 94.7 mol%, and 94.9% by weight (Example 3).

Example 4 4-chloroacetoacetic acid obtained in the same manner as in Example 1 was added to 469.6 g of an aqueous solution containing 0.475 mol of p-chlorophenyldiazonium chloride, and 285 ml of isopropanol was successively added while maintaining the temperature at 0°C. Ta.

Then add 1.2 mol of 30% sodium acetate to this solution.
The aqueous solution was added dropwise over 30 minutes at a reaction temperature of 0°C. Although a very small amount of carbon dioxide bubbles were observed during the dropping, the reaction generally proceeded gently and the formed crystals were not blown up at all. After the dropwise addition was completed, the mixture was stirred at room temperature for 90 minutes to obtain brown crystals. The crystal particles had a more uniform shape than those in Examples 1, 2, and 3, and were excellent in removal from the reaction vessel (flask), oxidation, and washing with water. In this way, 106.3 g of 3-chloropyruvaldehyde (4-chlorophenyl) hydrazone was obtained.

The structure of the compound was confirmed by NMR and IR. Also, the yield is at a melting point of 190-192℃ (decomposition temperature).
The content was 93.0 mol% and the purity was 96.0% by weight.

Example 5 In Example 4, an experiment was conducted using 140 ml of isopropanol, and the reaction proceeded slowly, and the shape of the crystal particles and the operability of the post-treatment were as good as in Example 4.

Yield: 93.5 mol%, purity 95.2% by weight Example 6 An experiment was conducted in Example 4 using methanol instead of isopropanol. The results were as good as in Example 4.

Yield: 92.0% mol%, purity: 96.0% by weight Example 7 Using dichloroethane as a solvent, 0.5 mole of bromine was charged into 0.5 mole of diketene over about 2 hours at a temperature of -10°C, and the reaction was carried out to obtain 4-bromoacetoacetic acid bromide. Ta. While maintaining the bromide-containing liquid at -10°C, 9 g of water was added to carry out hydrolysis, and hydrogen bromide was further removed to obtain 4-bromoacetoacetic acid. On the other hand, p-bromphenyldiazonium chloride was separately obtained using p-bromoaniline as a raw material. Thereafter, 4-bromoacetoacetic acid, p-bromphenyldiazonium, and isopropanol were reacted according to Example 4 to obtain 3-bromopyruvaldehyde (4-bromophenyl) hydrazone.

The reaction proceeded extremely gently, and the shape of the crystal particles, post-treatment operations, etc. were very good as in Example 4.

Yield: 93.4 mol% (based on p-bromoaniline), purity: 95.3% by weight.

Claims (1)

[Claims] 1. Reacting 4-halogenoacetoacetic acid and a halogen-substituted phenyldiazonium salt in a mixed solvent of a halogenated hydrocarbon and water or a mixed solvent of a halogenated hydrocarbon, water, and alcohol in the presence of a base. 3
- A method for producing halopyruvaldehyde phenylhydrazones. 2. Diketene and halogen are reacted in a halogenated hydrocarbon to obtain 4-halogenoacetoacetic acid halide, which is hydrolyzed in a mixed solvent with water to form 4-halogenoacetoacetic acid, and then alcohol is added as necessary. A method for producing 3-halopyrvaldehyde phenylhydrazones, which comprises reacting the same with a halogen-substituted phenyldiazonium salt in the presence of a base.