JPH08143540A - Substituted benzoic acid derivative and its production - Google Patents

Abstract

PURPOSE: To obtain a new readily producible substituted benzoic acid derivative useful as an intermediate for medicines and agrochemicals, e.g. an N-acyl-N- phenyltetrahydrophthalamic acid derivative having herbicidal activities. CONSTITUTION: The compound of formula I (Y is a halogen; R<4> is a lower alkyl), e.g. 5-acetylthio-4-chloro-2-fluorobenzoic acid. The compound of formula I is obtained by reacting (C) a compound of formula II with (D) a compound of the formula R<4> COOH in the presence of (A) red phosphorus and (B) an iodine- based catalyst such as iodine. Furthermore, the amounts of the respective components used in obtaining the objective compound are preferably 1.5-3.5equiv. component (A), 0.001-0.2equv. component (B) and 1.5-100equiv. component (D) based on 1 equiv. component (C). The reaction is carried out at 70-180 deg.C for 0.5-24hr.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the general formula [I]

[0002]

Embedded image

[Wherein Y represents a halogen atom and R ⁴
Represents a lower alkyl group. ] And a novel substituted benzoic acid derivative represented by The novel substituted benzoic acid derivative represented by the general formula [I] of the present invention is an intermediate for producing pharmaceuticals, agricultural chemicals, etc., for example, the general formula [XIII] having excellent herbicidal activity.

[0004]

[Chemical 6]

[In the formula, Y represents a halogen atom, and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, R ⁶ represents a lower alkyl group), and R ² represents a lower alkyl group or a substituted or unsubstituted phenyl group. R ³ represents a lower alkoxy group, a lower alkenyloxy group, a lower alkynyloxy group, a lower alkoxyalkoxy group or a lower alkoxycarbonylalkoxy group. ] It is a compound useful as a production intermediate such as an N-acyl-N-phenyltetrahydrophthalamic acid derivative represented by

[0006]

2. Description of the Related Art Conventionally, many substituted benzoic acid derivatives have been known. However, the substituted benzoic acid derivative represented by the general formula [I] has not been known so far and is a novel compound.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies, the present inventors have found that a substituted benzoic acid derivative represented by the general formula [I] has N-type represented by the general formula [XIII] having excellent herbicidal activity.
It was found that the compound is useful as an intermediate for the production of acyl-N-phenyltetrahydrophthalamic acid derivative,
Furthermore, the inventors of the present invention have earnestly studied a novel method for producing a substituted benzoic acid derivative represented by the general formula [I], which has industrial significance, and as a result, A substituted benzoic acid derivative represented by the general formula [I] can be easily produced by reacting the represented 5-sulfonyl-2-fluoro-4-halobenzoic acid with a lower alkylcarboxylic acid represented by the general formula [III]. The inventors have found that it can be done and completed the present invention.

That is, the present invention provides a compound represented by the general formula [I]:

[0009]

[Chemical 7]

[Wherein Y represents a halogen atom and R ⁴
Represents a lower alkyl group. ] A novel substituted benzoic acid derivative represented by the general formula [II]

[0011]

Embedded image

[In the formula, Y represents a halogen atom. ] 5-sulfonyl chloride-2-fluoro-4-halobenzoic acid represented by the general formula [III]

[0013]

[Chemical 9]

[In the formula, R ⁴ represents a lower alkyl group. ] In the presence of a lower alkylcarboxylic acid represented by the formula, red phosphorus and an iodine-based catalyst, the general formula [I]

[0015]

[Chemical 10]

[In the formula, Y represents a halogen atom, and R ⁴
Represents a lower alkyl group. ] It is a manufacturing method of the novel substituted benzoic acid derivative shown by these. Examples of the novel substituted benzoic acid derivative represented by the general formula [I] which is the compound of the present invention include 5-acetylthio-2,4-difluorobenzoic acid and 5-acetylthio-2-fluoro-4-chlorobenzoic acid. , 5-acetylthio-2-fluoro-4-bromobenzoic acid, 5-propionylthio-2,4-difluorobenzoic acid, 5-propionylthio-2-fluoro-4
-Chlorobenzoic acid, 5-propionylthio-2-fluoro-4-bromobenzoic acid, 5-butyrylthio-2,4-
Difluorobenzoic acid, 5-butyrylthio-2-fluoro-4-chlorobenzoic acid, 5-butyrylthio-2-fluoro-4-bromobenzoic acid, 5-isobutyrylthio-2,
4-difluorobenzoic acid, 5-isobutyrylthio-2-
Fluoro-4-chlorobenzoic acid, 5-isobutyrylthio-2-fluoro-4-bromobenzoic acid, 5-valerylthio-2,4-difluorobenzoic acid, 5-valerylthio-
2-fluoro-4-chlorobenzoic acid, 5-valerylthio-2-fluoro-4-bromobenzoic acid, 5-isovalerylthio-2,4-difluorobenzoic acid, 5-isovalerylthio-2-fluoro-4-chlorobenzoic acid, 5-isovalerylthio-2-fluoro-4-bromobenzoic acid, 5
-Pivaloylthio-2,4-difluorobenzoic acid, 5-
Pivaloylthio-2-fluoro-4-chlorobenzoic acid,
5-pivaloylthio-2-fluoro-4-bromobenzoic acid, 5- (2-methylbutanoylthio) -2,4-difluorobenzoic acid, 5- (2-methylbutanoylthio)-
2-fluoro-4-chlorobenzoic acid, 5- (2-methylbutanoylthio) -2-fluoro-4-bromobenzoic acid, 5-hexanoyl-2,4-difluorobenzoic acid,
5-hexanoyl-2-fluoro-4-chlorobenzoic acid, 5-hexanoyl-2-fluoro-4-bromobenzoic acid, 5- (2-methylheptanoyl) -2,4-difluorobenzoic acid, 5- (2 -Methylheptanoyl) -2
-Fluoro-4-chlorobenzoic acid, 5- (2-methylheptanoyl) -2-fluoro-4-bromobenzoic acid, 5
-(3-Methylheptanoyl) -2,4-difluorobenzoic acid, 5- (3-methylheptanoyl) -2-fluoro-4-chlorobenzoic acid, 5- (3-methylheptanoyl) -2-fluoro -4-Bromobenzoic acid, 5- (4-
Methylheptanoyl) -2,4-difluorobenzoic acid,
5- (4-methylheptanoyl) -2-fluoro-4-
Chlorobenzoic acid, 5- (4-methylheptanoyl) -2
-Fluoro-4-bromobenzoic acid, 5- (2,2-dimethylbutanoyl) -2,4-difluorobenzoic acid, 5-
(2,2-Dimethylbutanoyl) -2-fluoro-4-
Chlorobenzoic acid, 5- (2,2-dimethylbutanoyl)
-2-Fluoro-4-bromobenzoic acid, 5- (2,3-
Dimethylbutanoyl) -2,4-difluorobenzoic acid,
5- (2,3-dimethylbutanoyl) -2-fluoro-
4-chlorobenzoic acid, 5- (2,3-dimethylbutanoyl) -2-fluoro-4-bromobenzoic acid, 5- (3,
3-Dimethylbutanoyl) -2,4-difluorobenzoic acid, 5- (3,3-dimethylbutanoyl) -2-fluoro-4-chlorobenzoic acid, 5- (3,3-dimethylbutanoyl) -2 -Fluoro-4-bromobenzoic acid and the like can be mentioned.

Next, the method for producing the substituted benzoic acid derivative represented by the general formula [I] in the present invention will be described in detail.

[0018]

[Chemical 11]

[Wherein Y represents a halogen atom and R ⁴
Represents a lower alkyl group. In the production method of the present invention, 5-sulfonyl chloride-2-fluoro-4-halobenzoic acid represented by the general formula [II] is converted into a lower alkylcarboxylic acid represented by the general formula [III], red phosphorus and iodine-based compounds. By reacting for 0.5 to 24 hours in the presence of a catalyst, the substituted benzoic acid derivative represented by the general formula [I] which is the compound of the present invention can be easily produced.

The 5-sulfonyl chloride-2-fluoro-4-halobenzoic acid represented by the general formula [II] is, for example, 5-sulfonyl chloride-2,4-difluorobenzoic acid or 5-sulfonyl chloride-2-. Fluoro-4-chlorobenzoic acid, 5-sulfonyl chloride-2-fluoro-4-bromobenzoic acid and the like can be mentioned.

Examples of the lower alkylcarboxylic acid represented by the general formula [III] include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid,
2-methylbutanoic acid, hexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid,
2,2-dimethylbutanoic acid, 2,3-dimethylbutanoic acid, 3,3-dimethylbutanoic acid and the like can be mentioned.

The lower alkylcarboxylic acid represented by the general formula [III] is usually 1 equivalent or more per 1 equivalent of 5-sulfonyl-2-fluoro-4-halobenzoic acid chloride represented by the general formula [II]. , Preferably 1.5 equivalents to 100
It is good to use equivalents, more preferably 2.0 to 50 equivalents. When the amount is less than this range, a large amount of unreacted 5-sulfonyl-2-fluoro-4-halobenzoic acid chloride represented by the general formula [II] remains, which causes a decrease in yield and is economically disadvantageous. In addition, the post-treatment step is unfavorable for removing or recovering unreacted 5-sulfonyl chloride-2-fluoro-4-halobenzoic acid represented by the general formula [II]. Further, even if it is used in excess of this range, there is almost no change in the yield of the desired substituted benzoic acid derivative represented by the general formula [I],
The excessively added lower alkylcarboxylic acid represented by the general formula [III] remains unreacted and remains in a large amount, which is economically disadvantageous, and the unreacted general formula [II]
[I] is not preferable because a post-treatment step is required to remove or recover the lower alkylcarboxylic acid.

In the production method of the present invention, red phosphorus is used, and its amount is usually 5-sulfonyl chloride-
2-fluoro-4-halobenzoic acid is equivalent to 1.
The amount is 5 to 4.0 equivalents, preferably 1.7 to 3.5 equivalents, and more preferably 2.0 to 3.0 equivalents. When the amount is less than this range, the reaction does not proceed sufficiently, which causes a decrease in yield, which is economically disadvantageous.
In order to remove or recover unreacted 5-sulfonyl-2-fluoro-4-halobenzoic acid chloride represented by the general formula [II] and unreacted lower alkylcarboxylic acid represented by the general formula [III], This is not preferable because it imposes a load on the post-treatment process. Further, even if it is used in excess of this range, the yield of the desired substituted benzoic acid derivative represented by the general formula [I] is hardly changed, and excessively added red phosphorus remains unreacted in a large amount. However, it is economically disadvantageous, and the post-treatment process is burdened by the removal of unreacted red phosphorus, which is not preferable.

Examples of the iodine-based catalyst used in the production method of the present invention include iodine, an aqueous solution of hydroiodic acid, sodium iodide, potassium iodide and the like.

The iodine-based catalyst is usually used in an amount of 1 equivalent of 5-sulfonyl chloride-2-fluoro-4-halobenzoic acid.
0.0005 equivalent to 0.3 equivalent, preferably 0.001
Equivalent to 0.2 equivalent, more preferably 0.002 equivalent
It is recommended to use 0.1 equivalent. If it is less than this range, the reaction does not proceed sufficiently, which causes a decrease in yield,
It is not preferable because it may be economically disadvantageous, or it may cause a problem that the reaction rate decreases and it takes a long time to complete the reaction. Further, if it is used in excess of this range, there is almost no change in reaction rate, yield, etc., and it is economically disadvantageous, which is not preferable.

The reaction temperature is usually 50 ° C to 200 ° C.
℃, preferably 70 to 180 ℃, more preferably 1
It is preferable to set the temperature to 00 ° C to 150 ° C. When the temperature is lower than this range, the reaction does not proceed sufficiently, which causes a decrease in yield, which is economically disadvantageous, or the reaction rate is low and it takes a long time to complete the reaction. This may cause problems and is not preferable. Further, if the temperature is higher than this range, decomposition or the like may occur during the reaction, which causes a decrease in yield, which is economically disadvantageous, and a post-treatment step for removing decomposition products and the like. It is not preferable because it puts a load on.

In the production method of the present invention, after completion of the reaction,
The reaction solution was cooled to room temperature, and unreacted red phosphorus was filtered off.The filtrate was or was not concentrated, and water was added to the solution as it was, extracted with an organic solvent, and washed with water or a saturated saline solution. After that, the extract is subjected to post-treatments such as drying and concentration, or the reaction mixture is cooled to room temperature and unreacted red phosphorus is filtered off, and then concentrated or not concentrated and directly added to water. A crude product can be obtained by collecting the precipitated crystals by filtration, washing with water and drying.

The obtained crude product is subjected to purification operations such as recrystallization and column chromatography, if necessary,
The desired substituted benzoic acid derivative represented by the general formula [I] can be easily obtained.

The starting material, 5-sulfonyl-2-fluoro-4-halobenzoic acid chloride represented by the general formula [II], can be produced, for example, by the production method described in USP-3780027. .

A compound of the general formula [I] which is a compound of the present invention

[0031]

[Chemical 12]

[In the formula, Y represents a halogen atom, and R ⁴
Represents a lower alkyl group. ] The novel substituted benzoic acid derivative represented by the following formula can be derived to an N-acyl-N-phenyltetrahydrophthalamic acid derivative having excellent herbicidal activity by the following route, for example.

That is, the general formula [I]

[0034]

[Chemical 13]

[In the formula, Y represents a halogen atom, and R ⁴
Represents a lower alkyl group. ] A substituted benzoic acid derivative represented by the general formula [IV]

[0036]

Embedded image

[In the formula, Hal- represents a chlorine atom or a bromine atom, R ¹ represents -CHR ⁵ CO ₂ R ⁶ (provided that R ⁵ represents a hydrogen atom or a lower alkyl group, and R ⁶ represents a lower alkyl group. Represents.) Represents. ] By reacting with a halocarboxylic acid ester derivative represented by the formula [V]

[0038]

[Chemical 15]

[In the formula, Y represents a halogen atom, and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, and R ⁶ represents a lower alkyl group). ] The substituted benzenecarboxylic acid derivative represented by the formula [V] is obtained by chlorinating the derivative.
I]

[0040]

Embedded image

[In the formula, Y represents a halogen atom, and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, and R ⁶ represents a lower alkyl group). ] The substituted benzene carbonyl chloride derivative shown by these is obtained, and this is made to react with an inorganic azide, and general formula [VII]

[0042]

[Chemical 17]

[In the formula, Y represents a halogen atom, and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, and R ⁶ represents a lower alkyl group). ] The acid azide derivative shown by this is obtained, This is general formula [VIII]

[0044]

Embedded image

[In the formula, R ² represents a lower alkyl group or a substituted or unsubstituted phenyl group. ] The carboxylic acid derivative shown by or general formula [IX]

[0046]

[Chemical 19]

[In the formula, R ² represents a lower alkyl group or a substituted or unsubstituted phenyl group. ] By decomposing in the presence of a carboxylic acid anhydride derivative represented by the general formula [X]

[0048]

Embedded image

[In the formula, Y represents a halogen atom, and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, R ⁶ represents a lower alkyl group), and R ² represents a lower alkyl group or a substituted or unsubstituted phenyl group. Represents ] The anilide derivative represented by
According to the method described in Japanese Patent Application No. 4205, by reacting in the presence of a dehydrating chlorinating agent, a compound of the general formula [XI]

[0050]

[Chemical 21]

[In the formula, Y represents a halogen atom, and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, R ⁶ represents a lower alkyl group), and R ² represents a lower alkyl group or a substituted or unsubstituted phenyl group. Represents ] The imidoyl chloride derivative shown by this and this and general formula [XII]

[0052]

[Chemical formula 22]

[In the formula, R ³ represents a lower alkoxy group, a lower alkenyloxy group, a lower alkynyloxy group, a lower alkoxyalkoxy group or a lower alkoxycarbonylalkoxy group. ] By reacting with a carboxylic acid derivative represented by the formula [X]
III]

[0054]

[Chemical formula 23]

[Wherein Y represents a halogen atom and R ¹
Represents —CHR ⁵ CO ₂ R ⁶ (wherein R ⁵ represents a hydrogen atom or a lower alkyl group, R ⁶ represents a lower alkyl group), and R ² represents a lower alkyl group or a substituted or unsubstituted phenyl group. R ³ represents a lower alkoxy group, a lower alkenyloxy group, a lower alkynyloxy group, a lower alkoxyalkoxy group or a lower alkoxycarbonylalkoxy group. ] N-acyl-N-phenyl tetrahydrophthalamic acid derivative shown by these can be derived.

N-represented by the above general formula [XIII]
The acyl-N-phenyltetrahydrophthalamic acid derivative has excellent herbicidal activity and is widely applicable to fields, paddy fields, fruit trees, meadows, lawns, forests, non-agricultural lands, etc. On the other hand, it is a compound showing high safety. Therefore, the substituted benzoic acid derivative which is a novel compound represented by the general formula [I] of the present invention is an N-acyl-N-phenyltetrahydrophthalamic acid represented by the general formula [XIII] which is a compound useful as a herbicide. The production method of the present invention is useful as an intermediate for producing a derivative, and the production method of the present invention is also useful as a production method capable of easily producing the substituted benzoic acid derivative represented by the general formula [I].

[0057]

The present invention will be specifically described below with reference to examples and reference examples. Reference Example 1 5-Sulfonyl chloride-4-chloro-2-fluorobenzoate
Production of acid (compound represented by general formula [II]) 4-chloro-2-fluorobenzoic acid 7.2 g under ice cooling
(41.4 mmol) was added to 25.0 g of chlorosulfate. Warm to room temperature, react for 30 minutes, then 120
The temperature was raised to ° C and the reaction was carried out for 4 hours. The reaction solution was cooled to room temperature, poured into ice water, and this was extracted twice with 100 ml of ethyl acetate. The extract was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure to give a crude product.

The resulting crude product was recrystallized from n-hexane / ethyl acetate to obtain 7.4 g of the target 5-sulfonyl chloride-4-chloro-2-fluorobenzoic acid. Melting point = 149.0 ° C. to 150.0 ° C. ¹ H-NMR (CDCl ₃ , δ ppm) 7.54 (d, J = 9.7 Hz, 1 H), 8.85
(D, J = 13.0 Hz, 1H), 10.74 (bs,
1H) Example 1 5-Acetylthio-4-chloro-2-fluorobenzoic acid
(Compound represented by general formula [I]) 5-sulfonyl chloride-4-chloro-2-fluorobenzoic acid 7.67 g (28.1 mmol), red phosphorus 2.20 g
(70.2 mg atom) and 0.15 g iodine
(0.56 mmol) in 80 ml of acetic acid,
The reaction was performed at 0 ° C to 110 ° C for 3 hours. The reaction solution was cooled to room temperature, unreacted red phosphorus was filtered off, and the filtrate was concentrated,
The residue was poured into ice water, and this was extracted twice with 100 ml of ethyl acetate. The extract was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure to give a crude product.

The obtained crude product was recrystallized from n-hexane / ethyl acetate to obtain 6.85 g of the target 5-acetylthio-4-chloro-2-fluorobenzoic acid. Melting point = 140.0 ° C. to 141.5 ° C. ¹ H-NMR (CDCl ₃ , δppm) 2.50 (s, 3H), 7.40 (d, J = 10.1H)
z, 1H), 8.19 (d, J = 7.9Hz, 1H),
11.29 (bs, 1H) Reference Example 2 4-chloro-2-fluoro-5-methoxycarbonylme
Production of tylthiobenzoic acid (compound represented by general formula [V]
Material) 5-acetylthio-4-chloro-2-fluorobenzoic acid 7.40 g (30.0 mmol), methyl bromoacetate 6.88 g (45.0 mmol), methanol 35 ml
Were mixed, and potassium hydroxide 5.89 g (105 mmo
A solution prepared by dissolving l) in 7 ml of water was added dropwise at 5 ° C to 10 ° C. After completion of dropping, the mixture was reacted at 15 ° C to 20 ° C for 1 hour and poured into ice water. After adjusting the pH to 1-2 with concentrated hydrochloric acid, the mixture was extracted with ethyl acetate, the extract was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to give a crude product. Obtained.

The resulting crude product was recrystallized from n-hexane / ethyl acetate to give the desired 4-chloro-2-fluoro-
5-Methoxycarbonylmethylthiobenzoic acid 7.69 g
I got

Melting point = 147.0 ° C.-149.0 ° C. ¹ H-NMR (CDCl ₃ , δppm) 3.72 (s, 2H), 3.77 (s, 3H), 7.3
1 (d, J = 10.1 Hz, 1H), 8.15 (d, J
= 7.0 Hz, 1H), 10.1 (bs, 1H) Reference Example 3 4-chloro-2-fluoro-5-methoxycarbonylme
Preparation of cyruthiobenzoic acid chloride (shown by general formula [VI]
Compound) 4-chloro-2-fluoro-5-methoxycarbonylmethylthiobenzoic acid 8.17 g (29.3 mmol) and thionyl chloride 66.4 g (558 mmol) are mixed and reacted under reflux for 2 hours to obtain an excess amount. Thionyl chloride and volatile components were distilled off, and the residue was recrystallized from n-hexane / benzene to obtain 6.2 g of the target 4-chloro-2-fluoro-5-methoxycarbonylmethylthiobenzoic acid chloride.

Melting point = 78.0 ° C. to 80.0 ° C. ¹ H-NMR (CDCl ₃ , δppm) 3.72 (s, 2H), 3.77 (s, 3H), 7.3
2 (d, J = 10.1Hz, 1H), 8.21 (d, J
= 7.0 Hz, 1H) Reference Example 4 4-chloro-2-fluoro-5-methoxycarbonylme
Preparation of cyruthiobenzoic acid azide (shown by general formula [VII]
Compound) 4-chloro-2-fluoro-5-methoxycarbonylmethylthiobenzoic acid chloride 5.50 g (18.5 mmo
l) was dissolved in 40 ml of acetone and 1.2 g (18.5 mmol) of sodium azide dissolved in 7 ml of water was added at 0 ° C.
After the dropwise addition was completed, the reaction was carried out at 0 ° C to 5 ° C for 20 minutes. After completion of the reaction, the reaction solution was poured into ice water, and the precipitated product was collected by filtration and dried to give the desired 4-chloro-2 product.
5.26 g of -fluoro-5-methoxycarbonylmethylthiobenzoic acid azide was obtained.

Melting point = 69.0 to 70.0 ° C. (decomp.) ¹ H-NMR (CDCl ₃ , δppm) 3.69 (s, 2H), 3.74 (s, 3H), 7.2
8 (d, J = 10.1 Hz, 1H), 8.04 (d, J
= 7.0 Hz, 1H) Reference Example 5 5 -Acetylamino -2-chloro-4-fluorophenyl
Production of methyl ruthioacetate (Compound represented by the general formula [X]
Product) 4-chloro-2-fluoro-5-methoxycarbonylmethylthiobenzoic acid azide 1.0 g (3.29 mmol)
Was dissolved in 7 ml of acetic acid, 2 drops of concentrated sulfuric acid was added at room temperature, and the mixture was heated to 70 ° C. and reacted for 2 hours. After completion of the reaction, the mixture was cooled to room temperature, the reaction mixture was concentrated, the residue was poured into ice water, and the mixture was extracted with ethyl acetate. The extract was washed with water and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure to give crystals. Recrystallization from ethyl acetate / n-hexane gives the desired 5-acetylamino-2.
Methyl chloro-4-fluorophenylthioacetate 0.5
1 g was obtained.

Reference Example 6 N- (4-chloro-2-fluoro-5-methoxycarbo
Nylmethylthiophenyl) -acetimidoyl chloride
(Compound represented by the general formula [XI]) 10 g (34.3 mmol) of methyl 5-acetylamino-2-chloro-4-fluorophenylthioacetate and 7.14 g (34.3 mmol) of phosphorus pentachloride in 250 ml. It was suspended in benzene, heated to 60 ° C., and stirred for 1 hour.
After the reaction, the reaction solution was concentrated under reduced pressure to quantitatively obtain N- (4-chloro-2-fluoro-5-methoxycarbonylmethylthiophenyl) -acetimidoyl chloride as an oil.

Reference Example 7 N-acetyl-N- (4-chloro-2-fluoro-5-
Methoxycarbonylmethylthiophenyl) -3,4
Manufacture of 5,6-tetrahydrophthalamic acid methyl ester
Preparation ( Compound represented by the general formula [XIII]) N- (4-chloro-2-fluoro-5-methoxycarbonylmethylthiophenyl) -acetimidoyl chloride 10.6 g (34.3 mmol), 3,4,5, 6.95 g of 6-tetrahydrophthalamic acid monomethyl ester
(37.7 mmol) was dissolved in 50 ml of benzene, and 4.16 g of triethylamine dissolved in 10 ml of benzene.
(41.2 mmol) was added dropwise at 10 ° C or lower. After dropping, the mixture was stirred at 60 ° C. for 3 hours. After allowing to cool, it was washed with water and saturated saline and then dried over anhydrous magnesium sulfate. The solvent was concentrated to give crystals. Recrystallize from methanol,
5.09 g of N-acetyl-N- (4-chloro-2-fluoro-5-methoxycarbonylmethylthiophenyl)
-3,4,5,6-Tetrahydrophthalamic acid methyl ester was obtained.

[0066]

INDUSTRIAL APPLICABILITY The substituted benzoic acid derivative represented by the general formula [I] of the present invention is a compound useful as a herbicide such as pesticides and medicines, for example, N-acyl-N-phenyltetrahydrophthalamic acid derivatives. And a substituted benzoic acid derivative represented by the general formula [I] can be easily produced by the production method of the present invention.

Claims (5)

[Claims] 1. A compound represented by the general formula [I]: [In the formula, Y represents a halogen atom, and R ⁴ represents a lower alkyl group. ] The novel substituted benzoic acid derivative shown by these. 2. The novel substituted benzoic acid derivative according to claim 1, wherein the substituted benzoic acid derivative represented by the general formula [I] is 5-acetylthio-4-chloro-2-fluorobenzoic acid. 3. A compound represented by the general formula [II]: [In the formula, Y represents a halogen atom. ] Shown by 5]
Sulfonyl chloride-2-fluoro-4-halobenzoic acid can be prepared according to the general formula [III] [In the formula, R ⁴ represents a lower alkyl group. ] In the presence of a lower alkylcarboxylic acid represented by the formula: red phosphorus, and an iodine-based catalyst, reduction is carried out in the general formula [I] [In the formula, Y represents a halogen atom, and R ⁴ represents a lower alkyl group. ] The manufacturing method of the novel substituted benzoic acid derivative shown by these. 4. The method for producing a novel substituted benzoic acid derivative according to claim 3, wherein the substituted benzoic acid derivative represented by the general formula [I] is 5-acetylthio-4-chloro-2-fluorobenzoic acid. 5. The method for producing the novel substituted benzoic acid derivative according to claim 3 or 4, wherein the iodine-based catalyst is iodine.