JPS6135182B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method for producing chloropyridines substituted with a methyl group, a trichloromethyl group, or a trifluoromethyl group.

[Conventional technology]

Chlorpyridines substituted with a methyl group, trichloromethyl group or trifluoromethyl group are
Conventionally, they were manufactured only by methods that required multiple steps. For example, 2,5-dichloro-3-methylpyridine and 2,3-dichloro-5-methylpyridine are each 2-chloro-3-methyl-5-methylpyridine.
It was produced by diazotizing -aminopyridine or 2-chloro-3-amino-5-methylpyridine and substituting it with chlorine while decomposing it.

The above aminopyridine is obtained by chlorinating 3-methylpyridine to give 2-chloro-3-methylpyridine and 2-chloro-5-methylpyridine, and by nitration, converting these into 2-chloro-3-methyl-5-
Nitropyridine and 2-chloro-3-nitro-
It can be produced by reducing a nitro compound to 5-methylpyridine. Chlorination of 3-methylpyridine usually produces a number of isomers in addition to the desired compound. By chlorination of 2,3-dichloro-5-methylpyridine, 2,3-
Dichloro-5-trichloromethylpyridine can be obtained and converted to 2,3-dichloro-5-trifluoromethylpyridine by replacing the chlorine atom of the trichloromethyl group with a fluorine atom (for example, as described in European Patent Publication No. (See No. 004414). Also, by heating 2,4-dimethylpyrrole and chloroform in the gas phase at a temperature of about 550°C,
2-chloro-3,5-dimethylpyridine is the other 5
Obtained with various isomers [J.Chem.Soe.
See Perkin Trans. I, 1578-82 (1979)].

[Problem that the invention seeks to solve]

Now here is the following formula (In the formula, R is chlorine and R ¹ is a methyl or trifluoromethyl group, or R is a methyl, trichloromethyl or trifluoromethyl group and R ¹ is a methyl group, or R and R ¹ are a methyl group. It has been found that the chlorpyridines represented by the formula can be produced in good yields by a simple, economical and environmentally friendly method using readily available and inexpensive raw materials.

[Means for solving the problem] Namely, in the presence of a catalyst, (a) trichloroacetaldehyde is added to methylacrylonitrile or α-trifluoromethylacrylonitrile, or (b) 2,2-dichloropropionaldehyde, Pentachlorpropionaldehyde or 2.2
-Dichloro-3,3,3-trifluoropropionaldehyde is added to acrylonitrile, or (c) 2,2-dichloropropionaldehyde is added to methacrylonitrile, resulting in the following formula: (In the formula, R is chlorine and R ² is a methyl or trifluoromethyl group, or R is a methyl, trichloromethyl or trifluoromethyl group and R ² is hydrogen, or R and R ² are a methyl group. It can be produced by cyclizing the intermediate product shown in the following formula to form the compound of the formula.

[Effect]

A formally identical reaction to obtain 2,3,5-trichloropyridine from non-alkyl-substituted trichloroformbutyronitrile was published in European Patent Publication No.
Described in No. 12117. However, formylbutyronitrile of the formula substituted by a chlorinated methyl group or trihalogenated methyl group is cyclized to a chlorinated methyl group or trihalogenated methylpyridine of the formula while being aromatized. That could not have been predicted. This is because by the method of the invention it is no longer possible to obtain a methyl or trihalogenated methyl group on the ring and perform the elimination of water necessary for aromatization. Therefore, the expected product was rather a 2-pyridone derivative. Therefore, the results of the present invention can be said to be very surprising. The formation of an addition compound of the formula from 2,2-dichloro-propionaldehyde, perchlor- or 2,2-dichloro-3,3,3-trifluoroproionaldehyde also shows that the reactivity of trichloroacetaldehyde is different from that of its congeners. very different [e.g. Chem.Ber., 97 , 3322
(1964)], which is surprising especially since the mobility of chlorine in chloroacetaldehyde is considerably limited by other hydrocarbon substituents such as methyl, trichloromethyl or trifluoromethyl.

[Preferred mode for carrying out the invention]

The addition reaction is an open system or a closed system, preferably
It is carried out at a temperature of 70-160°C. Preferably, the addition reaction is carried out in a closed system under a pressure corresponding to the reaction temperature, for example in the range from 1 to 30 bar.

Catalysts for addition reactions in the process of the invention include metals from the main group and subgroups a, a, b and b of the periodic table, such as iron, cobalt, nickel, ruthenium, palladium, chromium, molybdenum, manganese, copper. and zinc can be used. These metals can be used both in their elemental state and in their compound state. Suitable compounds are, for example, oxides and halides, sulphates, sulphites, sulphides, nitrates, acetates, steriaphosphates, citrates, carbonates, cyanides,
They are complexes with salts such as rhodanides, and ligands such as phosphines, phosphites, benzoylacetone, acetylacetone, nitriles, isonitriles, and carbon monoxide.

Typical examples include:
Copper() oxide, iron() oxide; copper()−,
Copper () −, iron () − and iron () bromide, −
Iodides and especially - chlorides, zinc chloride and chlorides of ruthenium, rhodium, palladium, cobalt and nickel; copper () sulphates, iron () - and iron () sulphates; copper () sulphates and iron () ) nitrate; manganese () acetate, copper () acetate, copper () steriaphosphate, iron () citrate, copper () cyanide; ruthenium ()-dichloro-tris-triphenylphosphine, rhodium- Dichloro-tris-triphenylphosphine; chromium- and nickel acetylacetonate, copper ()-acetylacetonate, iron ()-acetylacetonate, cobalt ()- and cobalt ()-acetylacetonate, manganese ()-acetylacetonate , copper()benzoylacetonate; iron carbonyl-
Cyclopentadienyl complex; molybdenum carbonyl cyclopentadienyl complex, chromium tricarbonyl aryl complex; ruthenium ()-acetate complex, chromium- and molybdenum hexacarbonyl, nickel tetracarbonyl, iron pentacarbonyl, cobalt- and manganese carbonyl.

Mixtures of the above-mentioned metals with metal compounds and/or other additives, such as combinations of copper powder and one of the above-mentioned copper compounds; copper powder and lithium halides (such as lithium chloride) or isocyanides (tert-
(butyl isocyanide, etc.); mixtures of iron powder and iron() chloride, sometimes with the addition of carbon monoxide; mixtures of iron() chloride and benzoin; iron()- or iron () Mixtures of chlorides and trialkyl phosphites; mixtures of iron pentacarbonyl and iodine can also be used.

Preference is given to iron() and iron() salts and complexes, in particular iron()- and iron() chlorides, and iron powder; ruthenium() chloride, ruthenium() dichloro-tris-triphenylphosphine. , copper powder, bronze, copper() and copper() salts and complexes, such as copper() chloride, copper() chloride, copper() bromide, copper()
They are bromide, copper () acetate, copper () acetylacetonate, copper () benzoylacetonate, copper () sulfate, copper () nitrate, copper () cyanide and copper () iodide.

Particularly preferred are copper powder, bronze, copper ()- and copper () chloride or -bromide and copper ()
iodide, as well as mixtures thereof.

The catalyst usually has a concentration of about 0.01 to aldehydes.
It is used in an amount of 10 mol%, preferably 0.1-5 mol%.

The addition of the aforementioned aldehyde to acrylonitrile, methacrylonitrile or α-trifluoromethylacrylonitrile is preferably carried out in the presence of an inert organic solvent. Suitable solvents are those in which the catalyst is sufficiently soluble or capable of forming a complex with the catalyst, and is inert to the reaction components. Examples of suitable solvents include: Alkanecarboxylic acid nitriles, especially those having 2 to 5 carbon atoms, such as acetonitrile, propionitrile and butyronitrile; 3-alkoxypropionitriles in which the alkoxy group has 1 to 2 carbon atoms;
For example 3-ethoxypropionitrile and 3-
Ethoxypropionitrile; aromatic nitrile, especially benzonitrile; preferably having 3 to 3 carbon atoms
8 aliphatic ketones, such as acetone, diethyl ketone, methyl isopropyl ketone, diisopropyl ketone, methyl tert-butyl ketone; alkyl- and alkoxyalkyl esters of aliphatic monocarboxylic acids having 2 to 6 carbon atoms, such as methyl formate. and -ethyl esters, methyl acetate-, -ethyl-, -n-butyl- and -isobutyl esters and 1-acetoxy-2-methoxyethane; cyclic ethers such as tetrahydrofuran, tetrahydrofuran and dioxane; 1 to 4 dialkyl ethers, such as diethyl ether, di-n-
Propyl ether and diisopropyl ether; N·N-dialkylamides of alkanecarboxylic acids in which the alkyl group has 1 to 3 carbon atoms, such as N·N-dimethylformamide, N·N-dimethylacetamide, N·N-diethylacetamide; N・N-dimethylmethoxyacetamide;
Ethylene glycol and diethylene glycol alkyl ethers in which the alkyl group has 1 to 4 carbon atoms, such as ethylene glycol dimethyl-, -diethyl- and -di-n-butyl-
ether; diethylene glycol diethyl- and -di-n-butyl ether; phosphoric acid tris-N.N-dimethylamide (hexametapol
Hexametapol). Furthermore, excess acrylonitrile,
Methacrylonitrile or α-trifluoromethyl-acrylonitrile can also be used as solvent.

Preferred solvents for the addition reaction are alkanecarboxylic acid nitriles having 2 to 5 carbon atoms and 3-alkoxypropionitriles having 1 to 2 carbon atoms in the alkyl group, in particular acetonitrile, butyronitrile and 3-methoxy Propionitrile or unsaturated nitriles used as reaction components.

The intermediate product of formula is a new substance.

The cyclization of compounds of formula is carried out in open or closed systems at temperatures of about 0 to 220<0>C, especially about 100 to 200<0>C. Preferably the cyclization is carried out in an open system. During the cyclization in an open system, the presence of hydrogen chloride or a substance that forms hydrogen chloride under the reaction conditions, such as phosgene, boron trichloride, aluminum chloride, and alkyl groups each having 1 to 1 carbon atoms, is used. It is conveniently carried out in the presence of trialkylammonium chloride of 4, phosphorus pentachloride, phosphorus oxychloride or phosphorus trichloride. Preferably the cyclization is carried out in the presence of hydrogen chloride.

The cyclization is preferably carried out by simply heating the compound of the formula in the liquid or gas phase without the addition of a solvent. However, the cyclization can also be carried out in the presence of an organic solvent. Examples of organic solvents include chlorinated aliphatic hydrocarbons such as chloroform, methylene chloride and tetrachloroethane; optionally chlorinated aromatic hydrocarbons such as benzene;
Toluene, xylene and chlorobenzene; N/N- of alkanecarboxylic acids having 1 to 3 carbon atoms
Alkylamides, such as N·N-dimethylformamide, N·N-dimethylacetamide, N·N
-diethylacetamide and N.N-dimethylmethoxyacetamide; cyclic amides, e.g. N-
Methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone and N-methyl-ε-caprolactam; amides of carbonic acids, such as tetramethylurea and dimorpholinocarbonyl; phosphorous acid, phosphoric acid,
Amides of phenylphosphonic acid or alkylphosphonic acids in which the alkyl group has 1 to 3 carbon atoms, such as phosphoric triamide, phosphoric acid tris-(N.
N-dimethylamide), phosphoric acid trimorpholide,
Tripyrrolinide phosphate, phosphorous acid-tris-
(N/N-dimethylamide), methanephosphonic acid-
Bis-(N·N-dimethylamide); amides of sulfuric acid or aliphatic or aromatic sulfonic acids, such as tetramethylsulfamide, methanesulfonic acid dimethylamide or p-toluenesulfonic acid amide; aliphatics of the types mentioned above Ketones, cyclic ethers, dialkyl ethers, and ethylene glycol and diethylene glycol ethers,
and phosphorus trichloride and phosphorus oxychloride.

Preferred solvents for the cyclization are chloroform, methylene chloride, cyclic ether and diethyl ether in which the alkyl group has 1 to 4 carbon atoms, respectively;
In particular dioxane and diethyl ether, as well as N.
N-dialkylamides, especially N.N-methylformamide.

The process of the invention can advantageously be carried out by first isolating the compound of formula produced in the addition reaction and then cyclizing it in a second reaction step.
In this case, the individual reaction steps are carried out as described above.

According to a preferred embodiment of the invention, the aldehyde as defined above is prepared in a closed system in acetonitrile, butyronitrile or 3-methoxypropionitrile as a solvent at a temperature of 70 to 160°C. () or copper () chloride or bromide, or copper () iodide, or a mixture of these substances, in the presence of 0.1 to 5 mol% with acrylonitrile, methacrylonitrile or α-trifluoromethyl-acrylonitrile. The compound of formula obtained after reaction and separation of the solvent is cyclized in the open system at a temperature of 100 to 200 DEG C. in the presence of hydrogen chloride or a substance that forms hydrogen chloride under the reaction conditions to give a compound of formula.

However, it is also possible to carry out the addition reaction and the cyclization reaction in one operation without isolating the intermediate product of the formula. In this case, the aldehyde defined above and acrylonitrile, methacrylonitrile or α-
The reaction to obtain the chlorpyridines of the formula from trifluoromethylacrylonitrile is carried out at 70-220°C, especially
Preferably it is carried out at a temperature of 130-200°C. At this time, it can be carried out either in an open system or in a closed system. When the reaction is carried out in an open system, it is preferably carried out in the presence of hydrogen chloride or in the presence of a substance that forms hydrogen chloride under the reaction conditions. Such substances are, for example, phosgene, boron trichloride, aluminum chloride, trialkylammonium chlorides in which the alkyl group has in each case 1 to 4 carbon atoms, phosphorus pentachloride, phosphorus oxychloride or phosphorus trichloride. The one-step preparation of chlorpyridine of the formula is preferably carried out in a closed system under a pressure corresponding to the reaction temperature at hand, ie in the range, for example, from 1 to 50 bar. Particular preference is given to carrying out the synthesis of the compounds of the formula in one step in a closed system under a pressure of 1 to 30 bar.

This one-step synthesis is also advantageously carried out in the presence of a catalyst and in the presence of an inert organic solvent. Catalysts and solvents include those of the first type mentioned in connection with preferred catalysts and catalyst amounts.

Preferred solvents for the one-step process are alkanecarboxylic acid nitriles having 2 to 5 carbon atoms and 3-alkoxypropionitriles having 1 to 2 carbon atoms in the alkyl group. Particularly suitable solvents are acetonitrile, butyronitrile and 3-methoxypropionitrile or the excess unsaturated nitrile used as reaction component. After the reaction is completed, chlorpyridine of the formula can be prepared by the usual method,
For example, by distilling off the solvent and distilling the crude product,
In some cases, it can be isolated by steam distillation.

According to a further advantageous embodiment of the invention, the aldehyde and acrylonitrile, methacrylonitrile or α-trifluoromethylacrylonitrile are mixed in a closed system in the solvent acetonitrile, butyronitrile or 3-methoxypropionitrile, copper powder,
Bronze, copper() or copper() chloride or bromide, or copper() iodide, or a mixture of these substances, in the presence of 0.1-5 mol%, at 130-200°C, at the reaction temperature at the time Direct reaction under corresponding pressure gives chlorpyridines of formula.

2,2-dichloro-3, used as raw material
3,3-Trifluoropropionaldehyde is a new substance and has been used in the synthesis of 4-formyl-2,4-dichloro-5,5,5-trifluorovaleronitrile and 2,3-dichloro-5-trifluoromethylpyridine. used.

2,2-dichloro-3,3,3-trifluoropropionaldehyde is obtained by treating the corresponding olefin with ozone and reductively treating the reaction product.

The following are used as solvents; organic acids such as formic acid, acetic acid, propionic acid; esters of these acids such as ethyl acetate, methyl acetate, ethyl formate, methyl formate; aliphatic hydrocarbons, e.g. pentane,
Hexane, heptane, octane, cyclopentane, cyclohexane; chlorinated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride; water.

The reaction temperature depends on the nature of the solvent, but ranges from -90℃ to +
70°C, preferably -70°C to +30°C.

Reductive treatment of ozone decomposition products can be carried out by direct catalytic hydrogenation using hydrogen and optionally noble metal catalysts such as platinum, palladium, rhodium adsorbed on a support, or by direct catalytic hydrogenation using a reducing agent such as zinc or dimethyl sulfide. This can be done by adding

One preferred embodiment of this ozonolysis method is to ozonate 4,4-dichloro-5,5,5-trifluoro-2-pentenecarboxylic acid methyl ester in acetic acid at 20°C, and then the reaction mixture is Add an aqueous suspension of 2.2- from the mixture.
Dichloro-3,3,3-trifluoropropionaldehyde is directly distilled.

Chlorpyridines of the formula can be used for the preparation of various active substances in known manner - or via a number of intermediate steps.
Used in particular in the production of insecticides and herbicides (e.g. Swiss Patent No. 622170, European Patent Publication No. 00176, European Patent Publication No. 00483 and Swiss Patent No. 04414)
European Patent Application No. 818101818; German Publication No. 2812649 and German Publication No. 2748636; South African Patent No. 7802440; Japanese Patent Publication No. 54-
115380, 55-038356, 55-079369 and 56-39069 and Belgian Patent Specification No. 862325).

[Embodiments of the invention]

The present invention will be explained in more detail with reference to the following examples.

Example 1 (a) Production of 4-formyl-2-methyl-2,4,4-trichlorobutyronitrile 14.7 g of trichloroacetaldehyde, 13.5 g of methacrylonitrile and copper powder (Org.Synth.
Coll. Vol., 339), 0.3 g of the bronze was heated with 30 ml of acetonitrile in an enamel autoclave for 15 hours. After cooling, the solvent was distilled off at about 40-50° C. under reduced pressure using a water pump. 50 ml of diethyl ether was added to the residue and the precipitated copper sludge was filtered off. After distilling off the diethyl ether, the residue was rectified under high vacuum. A fraction boiling at 76-78 °C at 13 pa was collected. 4-formyl-2-methyl-2,4,4-
13.8 g of trichlorobutyronitrile was obtained as a colorless oil.

IR-spectrum (liquid film): 2250 (CN), 1750
(CO) cm ^-1 .

^1H -NMR-spectrum (60MHz, in CDCl ₃ ): 9.30 (s, 1H, -CHO); 3.22
(s, 2H, C-3 H ₂ ); 2.60 (s, 3H, -
_CH3 ) ppm.

Elemental analysis as C ₆ H ₆ Cl ₃ NO (molecular weight 214.48): Calculated values C 33.60% H 2.82% N 6.53% Cl 49.59% Actual values C 34.1% H 3.1% 6.8% Cl 48.6% (b) 2,5-dichlor -Production of 3-methylpyridine 4-formyl-2 obtained according to Example 1(a)
21.4 g of -methyl-2,4,4-trichlorobutyronitrile were heated to 145 DEG C. for 4-5 hours while introducing a weak stream of dry HCl gas. After cooling, the blackish melt was steam distilled. 2.5-
9.9 g of dichloro-3-methylpyridine was obtained as colorless crystals.

Melting point: 42°C (recrystallized from CH ₃ OH/H ₂ O volume ratio 4:1).

^1H -NMR-spectrum (60MHz, in CDCl ₃ ): 8.15 (d, 1H, H at C-6);
7.50 (d, 1H, H of C-4); 2.40 (s,
3H, _-CH3 ); ppm.

Elemental analysis _{as C6H5Cl2N} (molecular weight 162.02): Calculated C 44.48% H 3.11% N 8.65% _Cl 43.77% Actual C 44.4% H 2.9% N 7.9% Cl 53.8%.

Example 2 One-step production of 2,5-dichloro-3-methylpyridine 14.7 g of trichloroacetaldehyde, 13.5 g of methacrylonitrile, 0.5 g of copper() chloride and 40 ml of acetonitrile in a tantalum autoclave at 150° C. for 2 hours. , and then heated at 180°C for an additional 2 hours. After the solvent was distilled off, 50 ml of diethyl ether was added to the residue and the mixture was filtered. Diethyl ether was distilled off under reduced pressure with a water jet pump, and the residue was steam distilled. The crystalline product obtained was Example 1(b)
It was consistent with the compound obtained in .

Example 3 (a) Production of 4-formyl-2,4-dichlorovaleronitrile 2,2-dichloropropionaldehyde 12.7
g, 31.8 g of acrylonitrile, 0.3 g of copper powder and 30 ml of acetonitrile were heated to 120° C. for 12 hours in an enamel autoclave. The solvent and excess acrylonitrile were distilled off under water pump vacuum and the residue was dissolved in 50 ml of diethyl ether. The ether solution was filtered, concentrated and the residue was rectified under high vacuum. 4-formyl-2・4-
11.7 g of dichlorvaleronitrile was obtained as an oil.

Boiling point: 70-74℃/13pa IR-spectrum (liquid film): 2250 (CN), 1750
(CO) cm ^-1 .

^1H -NMR-spectrum (100MHz, in _CDCl3 ): 9.5 (s, 1H, -CHO); 4.75
(t, 1H, C-2 H); 2.3-3.1 (m,
2H, C-3 H) 1.78 (s, 3H, -CH ₃ )
ppm.

According to the ¹ H-NMR spectrum, two isomers were present in a ratio of approximately 1:1.

Elemental analysis _{as C6H7Cl2NO} (molecular weight 180.03): Calculated C 40.03% H 3.92% N 7.78% _Cl 39.39% Actual C 41.0% H 4.0% N 7.9% Cl 38.5%.

(b) Production of 2,3-dichloro-5-methylpyridine 4-formyl-2,4 obtained in Example 2(a)
-18.0g of dichlorvaleronitrile and 0.1g of copper powder
After pressurizing 10.0 g of dry HCl gas into a tantalum autoclave, the mixture was heated to 150° C. for 5 hours.
After cooling, the contents of the autoclave were steam distilled. 2,3-dichloro-5-methylpyridine
10.5 g was obtained as colorless crystals.

Melting point: 46-47°C ^1H -NMR-spectrum (100MHz, in _CDCl3 ): 81.3 (d, 1H, H at C-6);
7.59 (d, 1H, H of C-4); 2.34 (s,
3H, −CH3).

Elemental analysis as C ₆ H ₅ Cl ₂ N (molecular weight 162.02): Calculated value C 44.48% H 3.11% N 8.65% Cl 43.77% Actual value C 44.4% H 3.2% N 8.6% Cl 43.5% Example 4 2.3 -Dichloro-5-methylpyridine production by one step 2,2-dichloropropionaldehyde 12.7
g, acrylonitrile 8.0 g, copper () chloride 0.5
g and 40 ml of acetonitrile are heated to 180° C. for 2 hours in a tantalum autoclave. Dissolve the contents of the autoclave in 50 ml of diethyl ether,
Filter and concentrate the filtrate under reduced pressure. The residue was steam distilled. The crystalline product obtained is Example 3(b)
It was consistent with the substance obtained by.

Example 5 One-step preparation of 2,3-dichloro-5-trichloromethylpyridine 23.0 g of pentachloropropionaldehyde, 8.0 g of acrylonitrile, 0.5 g of copper() chloride and 40 ml of acetonitrile were heated to 170° C. in a tantalum autoclave for 30 minutes. heated for an hour. After cooling, the contents of the autoclave were dissolved in 50 ml of diethyl ether and filtered, and the filtrate was concentrated under reduced pressure. The residue was rectified to give 2,3-dichloro-5-trichloromethylpyridine (17.49g) with a boiling point of 147-149℃/1700pa.
Collected.

IR-spectrum (KBr): 3050, 1590, 1555,
1430, 1380, 1180, ^{1049cm -1} . ^1H -NMR-spectrum (100MHz, in CDCl ₃ ):
8.85 (d, J=5Hz), 8.25 (d, J=5Hz)
ppm.

Elemental analysis as C ₆ H ₂ Cl ₅ N (molecular weight 265.35): Calculated values C 27.15% H 0.75% N 5.27% Cl 66.80% Actual values C 27.1% H 0.9% N 5.3% Cl 66.4%.

Example 6 Production of 2,5-dichloro-3-trifluoromethylpyridine Using the same recipe as in Example 5, pentachlorpropionaldehyde was mixed with trichloroacetaldehyde 14.1
g and acrylonitrile to α-trifluoromethylacrylonitrile [Darrall et al. (Soc.
1951 , 2330)] to obtain 2,5-dichloro-3-trifluoromethylpyridine.

_nD25 = ^1.4825 .

Example 7 (a) 4-formyl-2-methyl-2,4-dichlorovaleronitrile 2,2-dichloropropionaldehyde 12.7
g, methacrylonitrile 13.5 g, copper() chloride 0.5 g and acetonitrile 40 ml in a tantalum autoclave at 130°C for 1 hour, then
Heat at 150℃ for 2 hours. After distilling off the solvent and steam distilling excess methacrylonitrile, the residue was dissolved in 50 ml of diethyl ether and filtered. The diethyl ether was distilled off under reduced pressure and the residue was rectified under high vacuum. A fraction boiling at 76-77 °C at 13 pa was collected. 4-formyl-2-methyl-2,4-dichlorovaleronitrile 10.8g
was obtained as an ocher oil.

IR-spectrum (liquid film): 2250, 1750 (CO)
cm ^-1 .

^1H -NMR-spectrum (60 MNz, in CDCl ₃ ): (1:1 diastereomeric mixture) 9.71 and 9.53, respectively (s, 1H, -
CHO); 2.96 (s, 4H, 2X- _CH2 ); 2.14
(s, 6H, 2X−CH ₃ ); 2.02 (s, 3H, −
_CH3 ); 1.93 (s, 3H, _-CH3 ) ppm.

Elemental analysis as _C7H9Cl2NO (molecular weight 194.06): Calculated C 43.22% H 4.67% N 7.21% _Cl 36.53% Observed C 43.6% H 4.6% _N 7.3% Cl 35.9%.

(b) Production of 2-chloro-3,5-dimethylpyridine 19.4 g of 4-formyl-2-methyl-2,4-dichlorovaleronitrile obtained in Example 7(a)
160-170 while introducing a weak dry HCl gas flow.
℃ for 4 hours. After cooling, the blackish melt was steam distilled. The effluent was extracted by shaking with diethyl ether, dried and concentrated under reduced pressure.
The remaining ocher oil was distilled. Boiling point of 7.36g of 2-chloro-3,5-dimethylpyridine
Obtained as an ocher oil at 110°C/2500pa.

^1H -NMR-spectrum (60MHz, in CDCl ₃ ): 8.0 (d, 1H, H at C-6);
7.31 (d, 1H, H of C-4, J6-4=2.0
Hz); 2.34 (s, 3H, -CH ₃ ); 2.28 (s,
3H, _−CH3 ) ppm.

Elemental analysis as C ₇ H ₈ ClN (molecular weight 141.60): Calculated values C 59.38% H 5.65% N 9.83% Cl 25.04% Actual values C 59.1% H 5.9% N 9.7% Cl 25.3%.

According to ¹ H-NMR data, this compound is J.
It corresponded to 2-chloro-3,5-dimethylpyridine described in Chem. Soc. PerKin I ( 1979 ), 1578.

Example 8 One-step production of 2-chloro-3,5-dimethylpyridine The same formulation as described in Example 7(b) except that acrylonitrile in Example 4 was replaced with 10.0 g of methacrylonitrile. -Chloro-3,5-dimethylpyridine was obtained.

Example 9 Production of 2,2-dichloro-3,3,3-trifluoropropionaldehyde 4,4-dichloro-5,5,5-trifluoro-2-methyl-2-pentenecarboxylic acid methyl ester (100.4g) 20 in a solution of glacial acetic acid (800ml)
19.2 g of ozone (mixture with oxygen) were introduced at . Next, a suspension of zinc powder (15 g) in water (15 ml) was added and distilled to produce 2,2-dichloro-
3.3.3-Trifluoropropionaldehyde was distilled under atmospheric pressure. 52.8 g of product was obtained as a colorless pungent liquid.

Boiling point: 66-67℃.

IR( _CCl4 ): ν(CO)1770cm ^-1 . ^1H -NMR-spectrum ( _CDCl3 ): δ=9.3
(q, J=2Hz) ppm.

Elemental analysis as C ₃ HCl ₂ F ₃ O (molecular weight 180.9): Calculated values C 19.92% H 0.56% N 31.50% Cl 39.19% Actual values C 20.2% H 0.8% N 30.9% Cl 38.5%.

(b) 4-formyl-2,4-dichloro-5,5.
Production of 5-trifluorovaleronitrile 36 g of 2,2-dichloro-3,3,3-trifluoropropionaldehyde, acetonitrile
80 ml of acrylonitrile and 0.5 g of copper() chloride are heated in a tantalum autoclave for 12 hours. Work-up according to Example 1(a) gives 4-formyl-2,4-dichloro-
5,5,5-trifluorovaleronitrile was obtained as a colorless oil. Boiling point 85-86℃/900pa.

IR (CCl ₄ ): ν(CN) 550cm ^-1 , ν(CO) 1750
cm ^{-1 1} H-NMR-spectrum (CDCl ₃ ): δ=9.56
(m, 1H, CHO); 4.7 (m, 1H, C-2-
3); 2.7-3.3 (m, 2H, 3-3H) ppm
(diastereomeric mixture).

Elemental analysis as C ₆ H ₄ Cl ₂ F ₃ NO (molecular weight 234.0): Calculated values C 30.80% H 1.73% N 5.99% Cl 24.36% Actual values C 31.5% H 2.0% N 5.9% Cl 23.8%.

(c) Production of 2,3-dichloro-5-trifluoromethylpyridine 4-formyl-2,4- obtained from Example 9(b)
25.0 g of dichloro-5.5.5-trifluorovaleronitrile was heated at 170° C. for 5 hours with 0.1 g of copper powder in a tantalum autoclave. Steam distillation yielded 11.9 g of 2,3-dichloro-5-trifluoromethylpyridine as a colorless oil with a peppery odor.

Boiling point: 80℃/3325pa.

^1H -NMR-spectrum ( _CDCl3 ): δ=8.63
(d, J=2Hz, 1H); 8.03(d, J=2
Hz, 1H) ppm.

Elemental analysis as C ₆ H ₂ Cl ₂ F ₃ N (molecular weight 216.0): Calculated value C 33.36% H 0.93% N 6.48% Cl 32.82% F 26.28% Actual value C 33.5% H 1.0% N 6.5% Cl 33.4% F 25.9% Example 10 One-step preparation of 2,3-dichloro-5-trifluoromethylpyridine The mixture used in Example 9(b) was heated and worked up as described in Example 2 to give 2. 3-dichloro-5-trifluoromethylpyridine was obtained. This corresponded to the product obtained in Example 9(c).

Claims (1)

[Claims] 1. In the presence of a catalyst, (a) trichloroacetaldehyde is added to methacrylonitrile or α-trifluoromethacrylonitrile, or (b) 2,2-dichloropropionaldehyde, pentachloropropion aldehyde or 2.2
-Dichloro-3,3,3-trifluoropropionaldehyde is added to acrylonitrile, or (c) 2,2-dichloropropionaldehyde is added to methacrylonitrile, resulting in the following formula: (In the formula, R is chlorine and R ² is a methyl or trifluoromethyl group, or R is a methyl, trichlor or trifluoromethyl group and R ² is hydrogen, or R and R ² are a methyl group. The following formula is characterized by cyclizing the intermediate product shown in (In the formula, R is chlorine and R ¹ is a methyl or trifluoromethyl group, or R is a methyl, trichloromethyl or trifluoromethyl group and R ¹ is chlorine, or R and R ¹ are a methyl group. A method for producing chlorpyridines represented by: 2. The method according to claim 1, wherein the addition reaction is carried out at a temperature of 70 to 160°C. 3. The method according to claim 1, wherein the addition reaction is carried out in a closed system at a temperature of 70 to 160°C and under a pressure corresponding to the reaction temperature. Claim 1, wherein the cyclization of the compound of formula 4 is carried out at a temperature of 0 to 220°C, preferably 100 to 200°C.
The method described in section. 5. The process according to claim 1, wherein the cyclization of the compound of formula 5 is carried out in a closed system at a temperature of 100 to 200 DEG C. in the presence of hydrogen chloride or a substance that produces hydrogen chloride under the reaction conditions. 6. The method according to claim 1, wherein the cyclization of the compound of the formula is carried out by heating in the liquid or gas phase without using a solvent. 7. The method of claim 1, wherein the compound of formula 7 is first isolated and then cyclized in a second step. 8 In the presence of a catalyst, (a) trichloroacetaldehyde and methacrylonitrile or α-trifluoromethacrylonitrile, (b) 2,2-dichloropropionaldehyde, pentachloropropionaldehyde or 2.
(c) 2-dichloro-3,3,3-trifluoropropionaldehyde and acrylonitrile, or (c) 2,2-dichloropropionaldehyde and methacrylonitrile without isolating a compound of the formula that is produced as an intermediate. 2. The method according to claim 1, wherein the method is directly reacted with a compound of the formula. 9. The reaction temperature is 70-220°C, preferably 130-220°C.
9. The method according to claim 8, which is carried out at a temperature of .degree. 10. The method according to claim 8, wherein the reaction is carried out in a closed system under a pressure corresponding to the reaction temperature at that time. 11. The method according to claim 1 or 8, in which copper powder, bronze, copper(), chloride or bromide of copper(), or iodide of copper(), or a mixture thereof is used as a catalyst. . 12 0.01 to 10 mol of catalyst to aldehyde
9. A method according to claim 1 or claim 8, wherein the amount is used in an amount of 0.1 to 5 mol%. 13. A process according to claim 1 or claim 8, wherein the addition reaction or direct reaction to obtain a compound of formula is carried out in the presence of an inert organic solvent. 14 The addition reaction or the direct reaction to obtain the compound of formula is carried out in an alkanecarboxylic acid nitrile having 2 to 5 carbon atoms as a solvent, in a 3-alkoxypropionitrile having an alkoxy group having 1 to 2 carbon atoms, or 9. The process according to claim 1 or 8, which is carried out in an excess of acrylonitrile, methacrylonitrile or α-trifluoromethacrylonitrile. 15 The addition reaction is carried out in a closed system at a temperature of 70 to 160°C in acetonitrile, butyronitrile or 3-methoxypropionitrile as a solvent, using copper powder, bronze, copper () or copper () chloride or bromide, or The reaction is carried out in the presence of 0.1 to 5 mol % of copper () iodide or a mixture of these substances, and the resulting compound of the formula is chlorinated with hydrogen chloride or under reaction conditions in an open system at a temperature of 100 to 200 °C. 14. A process according to claim 1 or claim 13, wherein the compound is cyclized in the presence of a hydrogen-producing substance to give a compound of formula. 16 Acetonitrile as a solvent for the reaction,
In the presence of butyronitrile or 3-methoxypropionitrile, in the presence of copper powder, bronze, copper() or copper() chloride or bromide, or copper() iodide or mixtures of these substances, 14. The process according to claim 8 or 13, characterized in that the reaction is carried out at a temperature of 130 to 200[deg.] C. and under a pressure relative to the reaction temperature.