JPH0414099B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on the general formula () [In the formula, R ₁ and R ₂ both represent a lower alkyl group, or R ₁ and R ₂ are engaged at the terminals to represent an alkylene group, and R ₃ represents a hydrogen atom or a lower acyl group. ] The present invention relates to an acetal derivative shown in the following and a method for producing the same. Recently, as a synthetic pyrethroid, the general formula () [In the formula, R ₄ represents a hydrogen atom or a chlorine atom,
R ₅ is a hydrogen atom, a cyano group, an ethynyl group, or 1
- represents a propynyl group. R ₆ is a general formula

[expression] or

[Formula] (where X represents a chlorine atom or a bromine atom). ] It has been discovered that the novel ester compound shown below has excellent insecticidal and acaricidal activity. As a result of various studies on the method of synthesizing the alcohol component of the ester compound represented by the above general formula (), the present inventors discovered that the acetal derivative represented by the above general formula () and the general formula () [In the formula, R ₄ has the same meaning as above. ] The bromobenzene derivative represented by the formula () is reacted with a base in the presence of copper or a copper compound, then deacylated if necessary, and then deacetalized to produce an ester compound represented by the above general formula (). The general formula () is the raw material for the synthesis of [In the formula, R ₄ has the same meaning as above. ] It was discovered that the aldehyde compound represented by the formula () can be obtained efficiently, and the acetal derivative represented by the above general formula () was found to be an important intermediate thereof, leading to the completion of the present invention. That is, the present invention provides an acetal derivative represented by the general formula () and a method for producing the same. [In the formula, R ₁ and R ₂ have the same meanings as above. ] General formula (′) obtained by catalytic reduction of the nitrobenzene derivative shown by [In the formula, R ₁ and R ₂ have the same meanings as above. ] A method for producing an acetal derivative represented by the general formula ('') by further reacting the acetal derivative with a lower carboxylic acid anhydride or a lower carboxylic acid halide. [In the formula, R ₁ and R ₂ have the same meanings as above,
R′ ₃ represents a lower acyl group. ] The present invention provides a method for producing an acetal derivative represented by the following. The present invention will be explained in detail below. In the acetal derivative represented by the general formula (), the substituents R ₁ and R ₂ are lower alkyl groups such as methyl group, ethyl group, n-propyl group, or R ₁ and R ₂ together. , represents an ethylene group, etc. In the method for producing the acetal derivative of the present invention represented by the general formula (), the catalyst used for the catalytic reduction of the nitrobenzene derivative represented by the general formula () is an aromatic nitrobenzene derivative represented by palladium-carbon or platinum dioxide. The usual catalysts used to reduce compounds to aniline derivatives are used,
The amount used is in the range of 0.01 to 10 mol%, preferably 0.1 to 5 mol%, based on the nitrobenzene derivative represented by the general formula (). Furthermore, examples of the solvent used in this catalytic reduction reaction include alcoholic solvents such as methanol and ethanol, and inert solvents such as ethyl acetate. The pressure of the hydrogen gas used is in the range of 1 to 10 atm, preferably 1 to 3 atm, and the reaction temperature is 0°C.
to the boiling point of the solvent used, preferably in the range of 10 to 30°C. After the catalytic reduction reaction as described above, the desired acetal derivative represented by the general formula (') can be obtained by removing the catalyst and distilling the catalyst off. It is desirable to dry the reaction solvent in advance. The acetal derivative represented by the general formula (') thus obtained is reacted with a lower carboxylic acid anhydride or a lower carboxylic acid chloride in the presence of a deoxidizing agent such as pyridine or triethylamine. The acetal derivative represented by the general formula ('') can be obtained by the reaction.The nitrobenzene derivative represented by the general formula () according to the present invention is obtained by adding p-toluenesulfone to 4-fluoro-3-nitrobenzaldehyde. It can be easily obtained by a normal acetalization reaction by reacting ethylene glycol, methyl orthoformate, ethyl orthoformate, etc. in the presence of an acid or sulfuric acid. will be explained in more detail, but of course the present invention is not limited thereto.Example 1 3.0 g of 4-fluoro-3-nitro-benzaldehyde ethylene acetal was dissolved in 100 ml of ethyl acetate, and platinum dioxide was added to the solution. 100 mg was added, and catalytic reduction reaction was carried out at room temperature for 3 hours while introducing hydrogen gas under normal pressure. At this point, no early absorption of hydrogen gas was observed, and gas chromatography of the reaction product showed that As a result of the analysis, no starting compound remained.Next, the reaction solution was filtered through Celite, and the obtained solution was dried over anhydrous magnesium sulfate, and the solvent was distilled off to obtain almost pure 3-amino-4-fluorocarbon. 2.5 g of -benzaldehyde ethylene acetal was obtained. Yield 97% mp 48-49.5°C Example 2 3.0 g of 4-fluoro-3-nitro-benzaldehyde ethylene acetal was added to 99.5% ethanol 100
ml and add 200 mg of 5% palladium-carbon to this.
was added, and a reduction reaction was carried out at room temperature for 3 hours while introducing hydrogen gas under normal pressure. Next, 200 mg of 5% palladium-carbon was further added to the reaction solution, and a catalytic reduction reaction was carried out under the same conditions for 1 hour. At this point, no premature hydrogen gas absorption was observed, and analysis of the reaction product by gas chromatography revealed that no starting compound remained. Next, the reaction solution was filtered through Celite, and the resulting solution was concentrated to about 50 ml, poured into 50 ml of saturated aqueous sodium bicarbonate solution, and extracted with ether. The organic layer was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and then the solvent was distilled off to obtain 2.7 g of the product as a residue. The product was dissolved in 20 ml of dry pyridine, and 2.0 g of acetic anhydride was added dropwise under ice cooling with stirring. After the dropwise addition, stirring was continued for further 8 hours at room temperature, and then the reaction solution was poured into 50 g of ice and extracted with ether. The organic layer was washed with water and an aqueous copper sulfate solution to remove pyridine, then further washed twice with a saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, and the solvent was distilled off to leave 2.6 g of the product as a residue. I got it. Then, the product was purified by silica gel column chromatography (eluent: chloroform),
1.90 g of pure 3-acetamino-4-fluoro-benzaldehyde ethylene acetal was obtained. Yield 59% mp 53.2℃ Reference example 1 4-fluoro-3-acetaminobenzaldehyde ethylene acetal 0.52g, potassium carbonate
0.42g, cuprous chloride 0.07g and bromobenzene
Put 3.62g into the reactor and bring the internal temperature to 140~140 under nitrogen flow.
The mixture was stirred at 150°C for 13 hours. After the reaction solution was allowed to cool, it was filtered through Celite, and the resulting solution was extracted twice with ether. The extract was washed once with a saturated aqueous sodium bicarbonate solution, dried over anhydrous sodium sulfate, and then the solvent was distilled off to obtain 0.95 g of the product as a residue. Next, 20 ml of 1N aqueous sodium hydroxide solution was added to the product, and after stirring at room temperature for 2 hours,
While cooling in a water bath, 20 ml of 10% hydrochloric acid was gradually added dropwise thereto, and the mixture was stirred for 2 hours after the dropwise addition. The reaction solution was extracted twice with ether, the extract was washed with a saturated aqueous sodium bicarbonate solution, and then dried over anhydrous magnesium sulfate, and the ether was distilled off. The obtained residue was purified by silica gel column chromatography (eluent: methylene chloride) to obtain pure 3-anilino-4-fluorobenzaldehyde.
0.40g was obtained. Yield 81% mp 115-117℃ Reference example 2 3-amino-4-fluorobenzaldehyde ethylene acetal 0.30g, potassium carbonate 0.27g,
Put 0.05 g of cuprous chloride and 1.30 g of bromobenzene into a reaction container, and heat at an internal temperature of 130 to 140°C under a nitrogen stream.
Stirred for 10 hours. After the reaction solution was allowed to cool, 10 ml of 10% hydrochloric acid was added thereto and stirred at 50°C for 2 hours.Then, the reaction solution was filtered through ceride, neutralized with an aqueous sodium hydroxide solution, and extracted twice with ether. . The extract was washed once with a saturated aqueous sodium hydrogen carbonate solution, dried over anhydrous magnesium sulfate, and then the solvent was distilled off. The obtained residue was purified by silica gel column chromatography (eluent: methylene chloride) to obtain pure 3-anilino-4-fluorobenzaldehyde.
0.14g was obtained. Yield 33% Reference example 3 4-fluoro-3-nitrobenzaldehyde 10
After dissolving 5.5 g of ethylene glycol and 100 mg of p-toluenesulfonic acid in 50 ml of toluene,
Azeotropic dehydration was carried out while 100 ml of toluene was added dropwise under heating under reflux, and about 100 ml of toluene liquid containing water was distilled out over a period of 2 hours. When the internal solution was analyzed by gas chromatography, the conversion rate of the raw material was 98%. After the reaction solution was allowed to cool, it was poured into a saturated aqueous sodium hydrogen carbonate solution, and the layers were separated. The organic layer was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and then the solvent was distilled off to obtain 12.3 g of 4-fluoro-3-nitro-benzaldehyde ethylene acetal as a pale yellow oil ( Yield: 97.6%). The product is shown in its gas chromatogram and
The NMR spectrum showed that it was almost pure. n ²² _D 1.5080 NMR data (CDCl ₃ , TMS) 6.80-7.80 (m, 3H) 5.70 (s, 1H) 3.90-4.10 (m, 4H) Example 3 2.43 g of 4-fluoro-3-nitrobenzaldehyde diethylacetal It was dissolved in 100 ml of ethyl acetate, 100 mg of platinum dioxide was added thereto, and a catalytic reduction reaction was carried out at room temperature for 6 hours under normal pressure while introducing hydrogen gas. At this point, no absorption of hydrogen gas was observed, and analysis of the reaction product by gas chromatography revealed that no starting compound remained. The reaction solution was then filtered through Celite, and the resulting solution was dried over anhydrous magnesium sulfate, and the solvent was distilled off to obtain 1.50 g of almost pure 3-amino-4-fluorobenzaldehyde diethyl acetal. Yield 70% n ^23.0 _D 1.5020 Reference example 4 4-Fluoro-3-nitrobenzaldehyde
Dissolve 5.0g in 13.1g of ethyl orthoformate,
- 100 mg of toluenesulfonic acid was added and left at room temperature for 5 hours. When the content liquid was analyzed by gas chromatography, the conversion rate of the raw material was 95%. Next, after distilling off excess ethyl orthoformate, vacuum distillation was performed to obtain 5.5 g of 4-fluoro-3-nitrobenzaldehyde diethyl acetal as a pale yellow oily substance. The compound has a gas chromatogram and
The NMR spectrum showed that it was almost pure. 102~108℃/0.1mmHg Yield 76% NMR data ( _CDCl3 , TMS, δ value) 7.10~8.30 (m, 3H) 5.50 (s, 1H) 3.55 (g, 4H) 1.20 (t, 6H) Reference example 5 4-fluoro-3-acetaminobenzaldehyde diethylacetal 1.0g, potassium carbonate
0.73g, cuprous chloride 0.13g and bromobenzene
Put 6.45g into a reaction container and heat it to an internal temperature of 140 under nitrogen flow.
Stirred at ~150°C for 15 hours. After the reaction solution was allowed to cool, it was filtered through Celite, and the supernatant was washed with ether. The resulting liquid was washed once with a saturated aqueous sodium bicarbonate solution, dried over anhydrous sodium sulfate, and the solvent was distilled off to form a residue.
1.98g of product was obtained. Next, 20 ml of 1N aqueous sodium hydroxide solution was added to the product, and the mixture was stirred at room temperature for 2 hours. Then, while cooling in a water bath, 20 ml of 10% hydrochloric acid was gradually added dropwise thereto, and the mixture was stirred for 2 hours. The reaction solution was extracted twice with ether, the extract was washed with a saturated aqueous sodium bicarbonate solution, and then dried over anhydrous magnesium sulfate, and the ether was distilled off. The obtained residue was purified by silica gel column chromatography (eluent: methylene chloride) to obtain pure 3-anilino-4-fluorobenzaldehyde.
0.49g was obtained. Yield 55%

Claims (1)

[Claims] 1. General formula [In the formula, R ₁ and R ₂ both represent a lower alkyl group, or R ₁ and R ₂ are bonded at the terminals to represent an alkylene group, and R ₃ represents a hydrogen atom or a lower acyl group. ] An acetal derivative represented by 2 General formula [In the formula, R ₁ and R ₂ both represent a lower alkyl group, or R ₁ and R ₂ are bonded at the terminal to represent an alkylene group. ] A general formula characterized by catalytic reduction of a nitrobenzene derivative represented by [In the formula, R ₁ and R ₂ have the same meanings as above. ] A method for producing an acetal derivative shown in 3 General formula [In the formula, R ₁ and R ₂ both represent a lower alkyl group, or R ₁ and R ₂ are bonded at the terminal to represent an alkylene group. ] The general formula obtained by catalytic reduction of the nitrobenzene derivative represented by [In the formula, R ₁ and R ₂ have the same meanings as above. ] A general formula characterized by reacting an acetal derivative represented by a lower carboxylic acid anhydride or a lower carboxylic acid halide. [In the formula, R ₁ and R ₂ represent the same meanings as above,
R′ ₃ represents a lower acyl group. ] A method for producing an acetal derivative shown in