JPH0315614B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing 3-phenoxybenzyl alcohol and its derivatives, and more specifically, the formula () [In formula (), X and Y are the same or different hydrogen atoms, halogen atoms, lower alkyl groups, or lower alkoxy groups, m is an integer of 1 to 5,
n represents an integer of 1 to 4. 3-phenoxybenzaldehydes represented by the formula () are reacted with dithionite in an aqueous medium to obtain α-hydroxy-3-phenoxybenzyl sulfinates represented by the formula (), [In the formula (), X, Y, m, and n represent the same meanings as in the above formula (), and M represents an alkali metal, an alkaline earth metal, or ammonium (1/2 equivalent in the case of an alkaline earth metal) ). ] Subsequently, in the presence of a base and a phase transfer catalyst, dithionite is added to react, or the formula ()
Reacting the dithionite salt in the presence of a base and a phase transfer catalyst in an aqueous medium with the formula () directly, without separation, to produce the formula () [In the formula (), X, Y, m, and n represent the same meanings as in the above formula ()]. Conventionally, 3-phenoxybenzyl alcohols are compounds useful as intermediate raw materials for agricultural chemicals, etc., and it has been known that the method for synthesizing them involves using 3-phenoxytoluenes as a raw material and oxidizing it in some way. Possible oxidation forms include halogenation from benzyl halide to alcohol, or oxidizing agents or free oxygen to obtain carboxylic acids or aldehydes, which are then reduced to alcohols. The former halogenation is not considered to be an economical method because halogen substitution on the active aromatic ring of the diphenyl ether type is unavoidable and its separation requires considerable cost. The latter method of reducing carboxylic acid cannot be said to be an industrially advantageous method because it needs to be carried out at high temperature and high pressure. Also, known methods for reducing aldehydes include methods using metal hydrides such as sodium borohydride, lithium borohydride, and lithium aluminum hydride, and methods using electrolytic reduction. Although this method is excellent as a laboratory synthesis method, it has drawbacks such as being expensive and difficult to carry out industrially. We have shown that when 3-phenoxybenzaldehyde or sodium α-hydroxy-3-phenoxybenzylsulfinate is reacted with sodium dithionite in the presence of a base and a phase transfer catalyst in an aqueous medium, 3 The present invention was completed after discovering that -phenoxybenzyl alcohol can be obtained in high yield and conducting extensive studies. The 3-phenoxybenzyl alcohols produced by the method of the present invention have the general formula () [In formula (), X and Y are the same or different hydrogen atoms, halogen atoms, lower alkyl groups, or lower alkoxy groups, m is an integer of 1 to 5,
n represents an integer of 1 to 4. ], and examples of these 3-phenoxybenzyl alcohols include the following compounds. 3-phenoxybenzyl alcohol, 3-(4
-fluorophenoxy)benzyl alcohol, 3
-(3-fluorophenoxy)benzyl alcohol, 3-(4-bromophenoxy)benzyl alcohol, 3-phenoxy-6-fluorobenzyl alcohol, 3-phenoxy-4-fluorobenzyl alcohol, 6-chloro-3- Phenoxybenzyl alcohol, 3-(4-methylphenoxy)
Benzyl alcohol, 3-(3,4-dichlorophenoxy)benzyl alcohol, 3-[3-(trifluoromethyl)phenoxy]benzyl alcohol, 3-(2-fluorophenoxy)benzyl alcohol, 3-(4 -methoxyphenoxy)benzyl alcohol, etc., and these are the corresponding 3
- Obtained from phenoxybenzaldehydes. In addition, in the method of the present invention, α-hydroxy-3 produced as a reaction intermediate between 3-phenoxybenzaldehyde and dithionite as a raw material
-Phenoxybenzylsulfinic acid may be isolated and used, and α-hydroxy-3-phenoxybenzylsulfinic acid can be represented by the formula (). [In the formula (), X, Y, m, and n represent the same meanings as in the above formula (), and M is an alkali metal, an alkaline earth metal, or ammonium (1/2 equivalent in the case of an alkaline earth metal) ), specifically sodium, potassium, lithium, calcium, barium, zinc, ammonium, etc. ] These α-hydroxy-3-phenoxybenzyl sulfinates can be synthesized and easily isolated by reacting the corresponding 3-phenoxybenzaldehyde with dithionite, but the reaction system It is also possible to obtain the desired product by subsequently adding dithionite without taking it out and reacting in the presence of a base and a phase transfer catalyst. The base used in the method of the present invention is
alkali metal and ammonium hydroxides,
carbonates, phosphates or borates, specifically sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, sodium carbonate,
Potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, tribasic sodium phosphate, tribasic potassium phosphate, tribasic ammonium phosphate, dibasic sodium phosphate, dibasic potassium phosphate, sodium pyrophosphate, metaphosphoric acid Sodium, sodium tripolyphosphate, sodium metaborate, potassium metaborate, ammonium metaborate, sodium tetraborate, potassium tetraborate, ammonium tetraborate, sodium pentaborate, potassium pentaborate, ammonium pentaborate, etc. These can be used alone or in combination of two or more. The amount of the base used is 0.5 to 50 molar ratio, preferably 1.0 to 10 molar ratio per mole of 3-phenoxybenzaldehyde and α-hydroxy-3-phenoxybenzyl sulfinate. If the amount used is less than this, the reaction rate is very slow and it is not economical, and if it is more than this, stirring becomes difficult. Even in the case of a two-step reaction in which dithionite is added cumulatively, the base may be added all at once at the beginning. The dithionite used in the method of the present invention includes sodium dithionite, potassium dithionite, lithium dithionite, ammonium dithionite, calcium dithionite, barium dithionite, Zinc dithionite and the like are used. The amount of dithionite used is α-hydroxy-3
-The molar ratio is from 0.1 to 50, preferably from 1.0 to 10, per mole of the phenoxybenzyl sulfinate. If the amount used is less than this, the reaction rate is very slow and it is not economical, and if it is more than this, stirring becomes difficult. The aqueous medium used in the method of the present invention includes water and/or lower alcohols such as isopropanol, ethanol, and methanol, ethers such as dioxane, tetrahydrofuran, and ethylene glycol dimethyl ether, N,N-dimethylformamide, and N,N-dimethyl. One or a combination of two or more of carboxylic acid amides such as acetamide and tetramethylurea, and sulfur-containing organic solvents such as sulfolane and dimethyl sulfoxide can be used, and the amount of the aqueous medium used is 3.
- 1 to 100 parts by weight, preferably 5 to 50 parts by weight, per 1 part by weight of phenoxybenzaldehyde.
If the amount used is less than this, stirring is difficult, and if it is more than this, productivity is low and uneconomical. Further, in the method of the present invention, the reaction rate and yield are increased by using a phase transfer catalyst. Examples of the phase transfer catalyst used include quaternary ammonium salts such as triethylbenzylammonium chloride, tetramethylammonium chloride, triethylbenzylammonium bromide, trimethylbenzylammonium chloride, tributylbenzylammonium chloride, trioctylmethylammonium chloride, 18-
Examples include crown ethers such as crown-6, dibenzo 18-crown-6, and dicyclohexano-18-crown-6. The amount of phase transfer catalyst used is not particularly limited, but is usually 0.1 to 20% by weight based on the raw materials 3-phenoxybenzaldehydes and α-hydroxy-3-phenoxybenzyl sulfinates.
It is. A typical embodiment of the method of the present invention is carried out, for example, by the following method. 3-phenoxybenzaldehydes or α-
Hydroxy-3-phenoxybenzyl sulfinates, base, dithionite, phase transfer catalyst, and aqueous medium are placed in a reaction vessel and heated to 50°C to boiling point, preferably 80°C to boiling point (however, boiling point (If the temperature exceeds 200℃, heating at 80-200℃ is preferable), at the same temperature for 0.5-100 hours, preferably 3-200℃.
Stir for 20 hours. After cooling to room temperature, drain into water and extract with an organic solvent such as carbon tetrachloride, benzene, or ether. After dehydrating the extract with a drying agent such as sodium sulfate, the solvent is evaporated off under reduced pressure to obtain 3-phenoxybenzyl alcohol. This product has high purity and can be used as is as a raw material for agricultural chemicals such as pyrethroid insecticides and acaricides, but in some cases it can be further purified by vacuum distillation or column chromatography. It is. Next, the details of the present invention will be explained by referring to examples. Example 1 9.91 g of 3-phenoxybenzaldehyde, 27.5 g of sodium bicarbonate, 12.5 g of sodium dithionite (hydrosulfite), and triethylbenzylammonium chloride are placed in a reaction vessel equipped with a stirring bar, thermometer, and condenser. 1.14g and water
Pour 200ml and heat to 95℃ while stirring. 95
Boil and reflux at ~99°C for 10 hours. After cooling to room temperature, it was drained into water and extracted three times with 150 ml of carbon tetrachloride. After drying the extract over sodium sulfate, the solvent was removed by distillation under reduced pressure to obtain 10.0 g of 3-phenoxybenzyl alcohol. The yield was quantitative, and as a result of gas chromatography analysis, the purity was 99.5%. (Yield 99.4%) The results of sampling during the reaction and analyzing it by gas chromatography are as follows.

[Table] Comparative Example 1 96-103℃ without using 1.14g of triethylbenzylammonium chloride in Example 1
The mixture was boiled and refluxed for 40 hours. After the same post-treatment, 9.93 g of a crude product was obtained. Analysis of this product by gas chromatography revealed that it was 88.2% 3-phenoxybenzyl alcohol and 11.7% 3-phenoxybenzaldehyde. The results of samples taken at intervals during the reaction and analyzed by gas chromatography are as follows.

[Table] Reference example 3-phenoxybenzaldehyde 9.91g, sodium dithionite 12.5g, isopropanol 15
ml and 100ml of water and heat to 80℃ while stirring. It was boiled and refluxed at 80-87°C for 8 hours. Then, 12.5 g of sodium dithionite was added and the mixture was boiled and refluxed for 8 hours. After cooling to room temperature, water 250
Drained into ml. The precipitated crystals are filtered, washed with a small amount of cold water, and dried to form colorless scaly crystals.
11.67g was obtained. mp132~182.5℃. Elemental analysis value (%) C53.5, H3.82, S10.10, Na7.32, N0.00 Calculated value as C ₁₃ H ₁₁ O ₄ SNa (%) C54.54, H3.87, S11.20 , Na8.03, N0.00 IRν (cm ^-1 );, 3250 (OH), 1585, 1485, 1450,
1250, 1190 (C-O-C), 1040, 940, 880,
760, 690, 630 NMR δ (ppm) (DMSO-d ₆ );, 5.3 (d, 1H,
CH), 6.1 (d, 1H, OH), 6.8-7.7 (m, 12H,
aromatic proton), 10.0 (s, -CHO) When the crystals obtained here were treated with an aqueous sodium hydroxide solution, they returned to the raw material 3-phenoxybenzaldehyde. From this, it is presumed that the crystals obtained here are sodium α-hydroxy-3-phenoxybenzyl sulfinate, to which a small amount of 3-phenoxybenzaldehyde is attached. It can be seen that in the absence of a base, even if a large amount of dithionite is subsequently added, the reaction to the desired product 3-phenoxybenzyl alcohols is not completed. Example 2 α-Hydroxy- synthesized by the method of Reference Example
Sodium 3-phenoxybenzylsulfinate
14.3g, sodium bicarbonate 27.5g, sodium dithionite (hydrosulfite) 12.5g
g, triethylbenzylammonium chloride
1.1 g was placed in an aqueous medium of 50 ml of isopropanol and 100 ml of water, and stirred under heating and reflux for 8 hours. After the reaction solution was cooled to room temperature, it was poured into 300 ml of water and extracted three times with 70 ml of carbon tetrachloride. After drying the extract over sodium sulfate, the solvent was distilled off under reduced pressure.
-Phenoxybenzyl alcohol was quantitatively obtained. This product was analyzed by gas chromatography and found to have a purity of 99.6%. Examples 3-8 Instead of 3-phenoxybenzaldehyde,
Using nuclear-substituted 3-phenoxybenzaldehydes in which the substituents of X and Y in formula () are shown in the table below, the corresponding 3-phenoxybenzyl alcohols were prepared in exactly the same manner as in Example 1. Synthesized. The results were as shown in Table 1.

【table】

Claims (1)

[Claims] 1 Formula () [In formula (), X and Y are the same or different hydrogen atoms, halogen atoms, lower alkyl groups, or lower alkoxy groups, m is an integer of 1 to 5,
n represents an integer of 1 to 4. ], characterized by reacting 3-phenoxybenzaldehyde represented by the formula () with a dithionite salt in an aqueous medium in the presence of a base and a phase transfer catalyst. [In the formula (), X, Y, m, and n represent the same meanings as in the above formula ()]. A method for producing 3-phenoxybenzyl alcohol. 2 formula () [In formula (), X and Y are the same or different hydrogen atoms, halogen atoms, lower alkyl groups, or lower alkoxy groups, m is an integer of 1 to 5,
n represents an integer of 1 to 4. 3-phenoxybenzaldehydes represented by the formula () are reacted with dithionite in an aqueous medium to produce α-hydroxy-3-phenoxybenzyl sulfine 3- represented by the formula ().
Obtain phenoxybenzyl alcohol salt, [In the formula (), X, Y, m, and n represent the same meanings as in the above formula (), and M represents an alkali metal, an alkaline earth metal, or ammonium (1/2 equivalent in the case of an alkaline earth metal) ). ] Subsequently, dithionite is added and reacted in the presence of a base and a phase transfer catalyst, formula () [In the formula (), X, Y, m and n represent the same meanings as in the above formula ()]. A method for producing 3-phenoxybenzyl alcohol.