JPS6251254B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing α,α,α-trichloro-o-toluic chloride. The present inventors first discovered that when o-Toluyk chloride () was photochlorinated under relatively mild conditions, it produced α,α,α-trichloro-o-Toluyk chloride () and 1,1,3 ,3-tetrachloro-
It has been found that a mixture containing 1,3-dihydroisobenzofuran () in a ratio of approximately 4:6 can be obtained in good yield. The reaction proceeds according to the path shown schematically below: In addition, there is a report in Journal of Chemical Society (J.Chem, Soc.), 221 , 2212 (1922) that compound () was obtained as a crystal with a melting point of 87°C by chlorinating compound () at 160 to 240°C for about 10 hours. is described, but the compound () has a boiling point of 120-123
Since it is a colorless and transparent oil with a temperature of ℃/0.5 mmHg, the description in this literature is not accurate. If a mixture of compounds () and () is directly reacted with anhydrous hydrogen fluoride, α,α,α-trifluoro-o-toluitsukfluoride can be synthesized in good yield, so this mixture itself can be reacted with anhydrous hydrogen fluoride. ,
It was found to be useful as a raw material for the synthesis of Truik fluoride (Japanese Patent Application No. 31300/1982). The photochlorination reaction from compound () to compound () proceeds easily, but the next step of photochlorination is slow. When the reaction temperature is raised, compounds () and () are accompanied by decomposition products and other by-products that reduce the yield, resulting in coloration and a decrease in chlorination efficiency. It is currently unclear what mechanism causes the colored substances, but chlorine gas contains a very small amount of metal from its container, and the metal acts as a catalyst, causing the compound () or and () to form with an unknown structure. Since it is thought that it may change into a substance, the inventors
While investigating compounds that have various metal-trapping effects in order to efficiently collect compounds () and (), we obtained an unexpected finding. That is, it has been found that when the photochlorination reaction is carried out in the presence of hexaalkylphosphoramide or tetraalkylurea, compound () is not obtained at all and only compound () is obtained in good yield. The present invention is based on this new knowledge. The reason why the production of compound (), which is the main product of the photochlorination reaction of compound () or (), is completely suppressed by the presence of hexaalkylphosphoramide or tetraalkylurea, and only compound () is produced. is not clear. Hexaalkylphosphoramide used in the present invention

[Formula] and tetraalkylurea

In the formula, the alkyl groups may be the same or different, and lower alkyl groups are particularly preferred. Representative examples include hexamethylphosphoramide and tetramethylurea. Acid amides such as urea, dimethylformamide, and dimethylacetamide are known as metal-trapping substances, but none of them have the effect of inhibiting the production of compound (). In carrying out the method of the present invention, it is sufficient that the hexaalkylphosphoramide or tetraalkylurea is present in such a manner that it can participate in at least the photochlorination reaction of the compound (), and from the time of photochlorination of the compound (). It may be made to exist in advance. The amount of hexaalkylphosphoramide and tetraalkylurea to be added may be set in the range of 0.1 to 5% (by weight) based on compound () or (), and the reaction temperature should be set in the range of approximately 50 to 200°C. can be used, but generally about 110 to
Perform at 140℃. This reaction can be carried out without a solvent or in a solvent, but the solvent is preferably one that is not affected by the photochlorination reaction, for example carbon tetrachloride is most commonly used. in this case,
The reaction temperature may be set in the reflux temperature range of the solvent. The light source can be selected from those commonly used in photochlorination reactions, such as sunlight,
Either an ultraviolet lamp or a tungsten lamp may be used. After the reaction is completed, the target compound can be collected from the reaction product by a conventional method. The end point of the reaction can also be determined by gas chromatography. The present invention will be explained in more detail below with reference to Examples. Example 1 α,α-dichloro-o-Toluyk chloride
18g (0.08mol) of hexamethylphosphoramide
Add 1 g (6.2 × 10 ^-3 mol) of dry chlorine at 110-120 °C under UV lamp irradiation. When the peak of the raw material α,α-dichloro-o-toluyk chloride disappears in gas chromatography, stop blowing chlorine. The reaction product was distilled under reduced pressure to obtain 21 g of α,α,α-trichloro-o-toluic chloride as a colorless and transparent oil. Chlorination yield 98%. Boiling point 103-104℃/0.1mmHg. When a part of the reaction product was analyzed by gas chromatography, no formation of 1,1,3,3-tetrachloro-1,3-dihydroisobenzofuran was observed. Furthermore, when a similar reaction was carried out using tetramethylurea, the desired product could be obtained in good yield, and no formation of isobenzofuran derivatives was observed. Example 2 11 g (0.071 mol) of o-Toluyzuk chloride and 0.5 g (3.1 x 10 ^-3 mol) of hexamethylphosphoramide were dissolved in 150 ml of carbon tetrachloride, and dried with chlorine at the reflux temperature of carbon tetrachloride under irradiation with an ultraviolet lamp. through. When the peak of α,α-dichloro-o-Toluyk chloride disappears in gas chromatography, stop blowing chlorine. Carbon tetrachloride was distilled off under reduced pressure, and the residue was distilled under reduced pressure to obtain 16 g of α,α,α-trichloro-o-toluic chloride as a colorless and transparent oil. Chlorination yield 87% Boiling point 120-123
°C / 0.5 mmHg Example 3 33 g (0.21 mol) of o-toluic chloride and 1 g (6 x 10 ^-3 mol) of hexamethylphosphoramide
Add dry chlorine at 80-85 °C under tungsten lamp irradiation. α by gas chromatography,
When the peak of α-dichloro-o-Toluik chloride disappears, stop blowing dry chlorine.
Carbon tetrachloride was distilled off under reduced pressure, and the residue was distilled under reduced pressure to obtain α,α,α-trichloro-o as a colorless and transparent oil.
- Obtain 50g of Toluitsuk Chloride. Chlorination yield
90% boiling point 103-104℃/0.1mmHg Example 4 Add 1g (8.6 x 10 ^-3 mol) of tetramethylurea to 42g (0.27 mol) of o-Toluizuk chloride.
Pass through dry chlorine under tungsten lamp irradiation at 95-110 °C. The mixture was treated in the same manner as in Example 3 to obtain 56 g of the target compound as a colorless and transparent oil. Chlorination yield: 82% Boiling point: 120-123℃/0.5mmHg Reference example 1 43g (0.278 mol) of o-Toluitsuko chloride was passed through dry chlorine under tungsten lamp irradiation to 110~
Chlorinate at 120℃. When the peak of α,α-dichloro-o-Toluyk chloride disappears in gas chromatography, stop blowing chlorine.
When the reaction product was analyzed by gas chromatography, it was found that 1,1,3,3-tetrachloro1,3-dihydroisobenzofuran and α,α,α-trichloro-o
-Toluyk chloride is produced in a ratio of approximately 6:4, yielding 67 g of a mixture. Chlorination ratio 93.4
% Similarly, 1,1,
43 g of a mixture containing 3,3-tetrachloro-1,3-dihydroisobenzofuran and α,α,α-trichloro-o-toluic chloride in a ratio of approximately 6:4 is obtained. Chlorination yield: 93.5% Reference example 2 0.5 g (5.5 x 10 ^-3 mol) of N,N-dimethylacetamide was added to 30 g (0.194 mol) of o-Toluyzc chloride, and the mixture was heated with dry chlorine under tungsten lamp irradiation to 100-110%. Chlorinate at °C. α,α-dichloro- by gas chromatography
Stop blowing chlorine when the o-Toluyk chloride peak disappears. This reactant contains 1,
1,3,3-tetrachloro-1,3-dihydroisobenzofuran and α,α,α-trichloro-o-
The yield of the mixture was 47.5 g, containing Trukk chloride in a ratio of approximately 6:4. Chlorination ratio
95% Similarly, 40g of o-Toluik chloride
(0.26 mol) and 1 g (0.014 mol) of dimethylformamide are photochlorinated to produce 1,1,3,3-tetrachloro-1,3-dihydroisobenzofuran 60 g of an approximately 6:4 mixture with chloride are obtained. Chlorination yield 90%

Claims (1)

[Scope of Claims] 1 α,α,α-trichloro-, which is characterized by photochlorinating α,α-dichloro-o-toluic chloride in the presence of hexaalkylphosphoramide or terraalkylurea. A method for producing o-Toluitsuk chloride. 2. The production method according to claim 1, wherein photochlorination is carried out in the presence of a hexaalkylphosphoramide or tetraalkylurea, which is a lower alkyl group in which the alkyl groups may be the same or different. 3. The manufacturing method according to claim 1, wherein the amount of hexaphosphoramide or tetraalkylurea is 0.1 to 5% (by weight) based on α,α-dichloro-o-toluic chloride. 4. The manufacturing method according to claim 1, wherein the hexaalkylphosphoramide is hexamethylphosphoramide. 5. The manufacturing method according to claim 1, wherein the tetraalkylurea is tetramethylurea. 6 α, α, α characterized by photochlorinating o-toluic chloride in the presence of hexaalkylphosphoramide or tetraalkylurea
-Production method of trichloro-o-toluitsuk chloride. 7. The production method according to claim 6, wherein the alkyl group is photochlorinated in the presence of a hexaalkylphosphoramide or tetraalkylurea, which is a lower alkyl group which may be the same or different. 8 The amount of hexaphosphoramide or tetraalkylurea relative to o-toluyuk chloride
The manufacturing method according to claim 6, wherein the amount is 0.1 to 5% (by weight). 9. The manufacturing method according to claim 6, wherein the hexaalkylphosphoramide is hexamethylphosphoramide. 10. The manufacturing method according to claim 6, wherein the tetraalkylurea is tetramethylurea.