JPS6223745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new compound, 2,4,4-trichloro-4-formylbutyronitrile, and a method for producing the same.

Conventionally known methods for producing 2,3,5-trichloropyridine are not satisfactory in various respects. For example, 2,3,5-trichloropyridine is produced by reacting chlorine on pyridine saturated with hydrogen chloride for several weeks.
It can be obtained by heating at ~220°C for a long time, or by heating dehydrated barium salt of pyridine-3,5-disulfonic acid and phosphorus pentachloride at about 200°C. However, in this case, the desired 2,3,5-
Along with trichloropyridine, other chlorpyridines, especially dichloropyridine and pentachlorpyridine, are produced in considerable amounts [J.Chem.Soc., 73 , 437
(1898), J.Chem.Sec., 93 , 2001 (1908) and
See Ber.Dtsch.Chem.Ges., 17 , 1832 (1884)].

2,3,5-trichloropyridine can also be prepared by the process of treating 2-amino-3,5-dichloropyridine with potassium nitrite in the presence of hydrogen halides, especially concentrated hydrochloric acid [Zentralblatt, 1671 (1928) and British Patent No. 1215387], or 1-methyl-
3,5-dichloropyrid-2-one, phosphorus pentachloride, and a small amount of phosphorus oxychloride or phosgene at 150%
Method of heating at a temperature of ~180℃ [J.Pr.Chem.(2),
93 , 371 (1916) and Ann.Chem. 486 , 71.
(1931)]. The raw materials required for these synthetic methods require many steps and are therefore only obtainable by uneconomical methods [e.g. J.Org.Chem., 23 , 1914 (1958), Ber.
dtsch.Chem.Ges., 31 , 609 (1898), same exam 32 ,
1297 (1899)]. From an ecological point of view, these conventional methods are not safe as they require large excesses of chlorinating agents and other auxiliary chemicals.
Moreover, the yield of 2,3,5-trichloropyridine is also somewhat unsatisfactory.

On the other hand, from British Patent No. 1024399, halogen compounds such as sulfonyl halogenides, allyl halogenides and halogen nitriles are added to ethylenically unsaturated compounds such as olefins, acrylic acid and acrylic acid derivatives having conjugated double bonds in the presence of a catalyst. It is known to encourage In this case, exclusively open-chain compounds are produced.

Finally, in German Publication No. 2709108, 3,5
A method for producing -dichloro-2-hydroxypyridine derivatives is described. According to this method, trichloroacetonitrile is reacted with an alkenyl aldehyde (for example, acrolein) or an alkyl alkenyl ketone (for example, methyl vinyl ketone) with the addition of a radical initiator.
The 2,2,4-trichloropentan-5-one-carboxylic acid nitrile derivative produced at this time is cyclized thermally or by the action of a Lewis acid, and then hydrogen chloride is eliminated to form 3,5-dichloro- It can be converted into a 2-hydroxypyridine derivative.

We now know that 2,3,5-trichloropyridine can be produced in a very simple, economical, and environmentally friendly manner in good yields using readily available and inexpensive raw materials. 2,4,4 of the general formula obtained by addition to acrylonitrile in the presence of
-Trichlor-4-formylbutyronitrile It has been discovered that 2,3,5-trichloropyridine can be produced by cyclodehydration of 2,3,5-trichloropyridine.

It is therefore an object of the present invention to provide a new 2,4,4-trichloro-4-formylbutyronitrile and a process for its production, which are particularly useful as starting materials for the production of 2,3,5-trichloropyridine. There is a particular thing.

2,4,4-trichloro-4-formylbutyronitrile is produced by adding trichloroacetaldehyde to acrylonitrile in the presence of a catalyst.

The addition of trichloroacetaldehyde to acrylonitrile is carried out in an open or closed system at temperatures of 70-140°C. Preferably this addition is a closed system;
It can be carried out at a corresponding pressure at the temperature at which the reaction is then carried out, for example a pressure in the range from 1 to 30 bar.

According to the invention, copper powder, bronze, copper salts or mixtures thereof are used as catalysts for the addition of trichloroacetaldehyde to acrylonitrile.

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

The catalyst is generally about 0.01 to acrylonitrile
~10 mol%, preferably 0.1-5 mol%.

The addition of trichloroacetaldehyde to acrylonitrile is advantageously carried out in the presence of an inert organic solvent. Suitable solvents are those that can sufficiently dissolve or form a complex with the catalyst and are inert towards trichloroacetaldehyde and acrylonitrile. 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 alkyl group has 1 to 2 carbon atoms; For example, 3-methoxypropionitrile and 3-ethoxypropionitrile; aromatic nitriles, especially benzonitrile; aliphatic ketones preferably having a total number of carbon atoms of 3 to 8, such as acetone, diethyl ketone, methylisopropyl ketone, diisopropyl ketone, Methyl-t-butyl ketone;
Alkyl and alkoxyalkyl esters of aliphatic monocarboxylic acids having a total number of 2 to 6 carbon atoms, such as methyl formate, ethyl formate, methyl, ethyl, n-butyl and isobutyl esters of acetate, and 1-acetoxy-2-
Methoxyethane; cyclic ethers such as tetrahydrofuran, tetrahydropyran and dioxane; dialkyl ethers in which the alkyl group has 1 to 4 carbon atoms, 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 and N,N-dimethylmethoxyacetamide;
Ethylene glycol dialkyl ethers and diethylene glycol dialkyl ethers in which the alkyl group has 1 to 4 carbon atoms, such as dimethyl, diethyl and di-n-butyl ether of ethylene glycol; diethyl and di-n-butyl ether of diethylene glycol; tris-phosphoric acid
N,N-dimethylamide (hexametapol)
Hexametapol). Furthermore, excess acrylonitrile can also be used as a solvent.

Preferred solvents for the addition of trichloroacetaldehyde to acrylonitrile are alkanecarboxylic acid nitriles having 2 to 5 carbon atoms and 3-alkoxypropionitriles in which the alkyl group has 1 to 2 carbon atoms, especially acetonitrile, butyronitrile, acrylonitrile and 3- It is methoxypropionitrile.

The method of the present invention will be explained in more detail by the following examples. The production of 2,3,5-trichloropyridine by cyclization of the obtained 2,4,4-trichloro-4-formylbutyronitrile is described in each example as a reference example.

Example 1 a Production of 2,4,4-trichloro-4-formylbutyronitrile 22.0 g of trichloroacetaldehyde, 5.3 g of acrylonitrile and 0.5 g of copper() chloride were heated to 115°C for 20 hours in an enamel autoclave with 30 ml of acetonitrile. Heat. After cooling, the solvent is distilled off at about 40-50°C under reduced pressure with a water pump.
The residue is diluted with 50 ml of diethyl ether and the copper() chloride precipitate is separated off. After distilling off diethyl ether, the residue was rectified under high vacuum,
Collect the fraction with a boiling point of 64-65 °C at 400 Pa. 2,
13.6 g (60% of theory) of 4,4-trichloro-4-formylbutyronitrile are obtained as a colorless oil.

IR-spectrum (CHCl ₃ ): 2250 (CN),
1750(CO)cm ^-1 , ^1H -NMR-spectrum (60MHz, CDCl ₃ solution): 9.15(s, 1H, -
CHO), 4.85 (t, 1H, C-2 H), 3.1
(d, 2H, 2H of C-3) ppm. _{C5H4Cl3NO _ _}
Elemental analysis for (molecular weight 200.45) Calculated value C29.96% H2.01% N6.99% Cl53.06% Experimental value C29.89% H 2.13% N6.95% Cl52.67% b 2,3,5-trichlor Production of pyridine 2,4,4-trichlor-4 obtained in a)
- 13.6 g of formylbutyronitrile was added to 1.0 g of AlCl ₃ in an enamel autoclave for 1 hour.
Heat to 60℃. The blackish crude product is then steam distilled to remove 2,3,5-
Trichloropyridine precipitates as white crystals. The yield of 2,3,5-trichloropyridine is
9.1 g (83% of theory), melting point 49-50°C.

Example 2 a 14.7 g of trichloroacetaldehyde, 5.3 g of acrylonitrile and 0.5 g of copper()-chloride in 40 ml of 3-methoxypropionitrile at 80-85
Heat to ℃. As the reaction progresses, the boiling point of the mixture increases and reaches 125-130°C after about 30 hours. After cooling, the blackish contents of the flask are extracted with ether. After distilling off the diethyl ether, the remaining brown oil is heated to 100° C. (bath temperature) under the vacuum of a water jet pump, and 3-methoxypropionitrile is distilled out. The residue is rectified under high vacuum. 10.2 g (51% of theory) of a colorless oil identical to the product obtained in Example 1a) are obtained.

b 2,4,4-trichloro-4-formylbutyronitrile obtained in a) above for 3 hours 130
℃, followed by steam distillation 2,3,
5-Trichloropyridine (yield, 80% of theory).

Example 3 a Production of 2,4,4-trichloro-4-formylbutyronitrile 14.7 g of trichloroacetaldehyde, 13.2 g of acrylonitrile and copper powder (Org.Synth.
Coll. Vol., 339, 0.63 g) are heated to 105° C. for 12 hours in a pressure reactor. Next, excess acrinitrile was added under reduced pressure using a water pump for 40~
Distill at 50℃. 18.2 g of a dark oil is obtained as a residue. According to gas chromatography analysis, 85.4% of this material is 2,4,4-trichlor
4-formylbutyronitrile, with a theoretical amount of
This corresponds to a yield of 77%.

b Production of 2,3,5-trichloropyridine 2,4,4-trichlor-4 obtained in a)
- A vertical mantle tube with a length of 40 cm and a diameter of 2.5 cm, half of which was filled with Lasith Healing, with formylbutyronitrile (18.2 g) heated within 15 minutes to 175-180°C with hot oil. Drip into. At the same time, hydrogen chloride is passed in a weak countercurrent to the reaction mixture from below. The dark resinous material that falls from the reactor is steam distilled. 2, 3, 5
-Trichloropyridine 11.5g (85% of theory)
is obtained as white crystals. Melting point 49-50℃.

Example 4 a Production of 2,4,4-trichloro-4-formylbutyronitrile 14.7 g of trichloroacetaldehyde, 13.2 g of acrylonitrile and bronze (Org.Synth.,
Coll. Vol., 339) 0.63 g of the mixture is heated under reflux for 48 hours. Next, add excess acrylonitrile.
Distill under reduced pressure with a water pump at 40-50°C.
17.3 g of a blackish oil is obtained as a residue. According to gas chromatography analysis, 88.5% of them are 2,
4,4-trichloro-4-formylbutyronitrile, corresponding to a yield of 76.5% of theory.

b 2,3,5-trichloropyridine 2,4,4-trichlor-4 obtained in a)
-Formyl-butyronitrile (17.3g), 24
Heat at 80-85°C for an hour while introducing hydrogen chloride weakly. The entire reaction mixture is then steam distilled. 2,3,5-trichloropyridine 10.0g
(72% of theory) is obtained as white crystals. melting point
49-50℃.

Claims (1)

[Claims] 1 2,4,4-trichloro-4-formylbutyronitrile. 2. A method for producing 2,4,4-trichloro-4-formylbutyronitrile, which comprises adding trichloroacetaldehyde to acrylonitrile in the presence of a catalyst. 3. The process according to claim 2, wherein the addition of trichloroacetaldehyde to acrylonitrile is carried out in the presence of an organic solvent at a temperature of 70 to 140°C. 4. The method according to claim 2 or 3, wherein the addition of trichloroacetaldehyde to alklonitrile is carried out in the presence of excess acrylonitrile as a solvent. 5. The manufacturing method according to claim 2, wherein copper powder, bronze, copper salt, or a mixture thereof is used as a catalyst for the addition of trichloroacetaldehyde to acrylonitrile. 6. Process according to claim 2 or 5, characterized in that the catalyst for the addition of trichloroacetaldehyde to acrylonitrile is used in an amount of 0.01 to 10 mol %, preferably 0.1 to 5 mol %, based on the acrylonitrile.