JPH07206863A - Substituted and condensed piperidiondione derivative and herbicide - Google Patents

Abstract

PURPOSE:To obtain a new compound, capable of manifesting high herbicidal activities, excellent in selectivity and useful as a herbicide. CONSTITUTION:This compound is expressed by formula I [R<1> is phenyl, pyridine, etc.; R<2> and R<3> each is H, a halogen, etc.; n is 0 or 1; R<4> is H or a 1-4C alkyl; A is a 1-4C alkylene chain] or its salt e g 6-(3-methoxy-2-methyl-4- methylsulfonylbenzoyl)-1,2,3,6,8,8a-hexahydroindolin-5,7dione. The compound is obtained by reacting a compound expressed by formula II and a compound expressed by the formula R<1>COOH with dicyclohexylcarbodiimide (DCC) in a solvent such as THF at -10 to +50 deg.C, providing a compound expressed by formulas III and IV and then reacting the resultant compound expressed by formulas III and IV in the presence of a cyano compound and a mild base using a phase-transfer catalyst such as a crown ether, e.g. in a solvent at ambient temperature to 40 deg.C. Furthermore, the compound expressed by formula II is a new compound and obtained by starting from, e.g. ethyl N- ethyoxycarbonylacetylpyrrolidine-2-acetate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel substituted fused piperidinedione derivative and a herbicide.

[0002]

2. Description of the Related Art In the cultivation of agricultural and horticultural crops, many herbicides have come to be used for controlling weeds, which have required a great deal of labor. However, since it causes phytotoxicity to crops, remains in the environment, and pollutes, it is desired to develop a drug that has a lower dose and is effective, and can be used safely.

[0003]

An object of the present invention is to provide a herbicide which can be synthesized industrially advantageously, has a low dose, is highly effective, has high safety, and is highly selective to crops. is there.

[0004]

The present invention has the general formula [I]

[0005]

[Chemical 5]

(Wherein R ¹ represents phenyl which may be substituted, pyridine which may be substituted, aralkyl which may be substituted, R ² and R ³ are each independently hydrogen,
Halogen, C1-4 alkyl, C1-4 alkoxy C1
~ 4 alkyl, C1-4 alkoxy, C1-4 alkylthio, C1-4 alkylsulfinyl, C1-4 alkylsulfonyl, C1-4 alkoxycarbonyl, carboxyl, and n is 0 or 1. Also R ² and R
³ may together represent a C2-4 alkylene chain. R ⁴ represents a C1~4 alkyl. A is C1-4
Represents an optionally substituted alkylene chain, and as the substituent, C1-4 alkyl, C1-4 alkoxy, C1-4 alkyl, C1-4 alkoxy, C1-4 alkylthio,
C1-4 alkylsulfinyl, C1-4 alkylsulfonyl, halogen, oxo and thioxo. And a substituted fused piperidinedione derivative represented by the formula (1) or a salt thereof, a synthetic intermediate thereof and a herbicide.

The phenyl, pyridine and aralkyl substituents for R ¹ are, for example, halogen, OR ⁵ (R
⁵ is C1-4 alkyl, C2-4 alkenyl, C2-
4 alkynyl, C1-4 haloalkyl, C2-4 haloalkenyl, phenyl, halophenyl, C1-4 alkoxy-substituted phenyl, phenyl C1-4 alkyl, halophenyl C1-4 alkyl, C1-4 alkoxy-substituted phenyl C1-4 alkyl, C1 4 alkylthio C1-4 alkyl, C1-4 alkylsulfonyl C1-4 alkyl, C1-4 alkoxy C1-4 alkyl, alkoxy C1-4 alkoxy C1-4 alkyl, C1-4 alkoxycarbonyl C1-4 alkyl, carboxy C1-4
Alkyl, cyano C1-4 alkyl, C1-4 alkylcarbonyl C1-4 alkyl, C3-6 cycloalkyl C1-4 alkyl, provided that cycloalkyl may contain 1 to 2 oxygen atoms), C1 5 alkyls,
C2-4 alkenyl, C2-4 alkynyl, C1-4 haloalkyl, C2-4 haloalkenyl, C1-4 alkoxy C1-4 alkyl, C1-4 alkylthio C1-4
Alkyl, C1-4 alkylsulfinyl C1-4 alkyl, C1-4 alkylsulfonyl C1-4 alkyl,
^{S (O) mR 6 (R} 6 is, C1 -4 alkyl, C2-4
Alkenyl, C2-4 alkynyl, C1-4 haloalkyl, C2-4 haloalkenyl, phenyl, halophenyl, benzyl, halobenzyl, C1-4 alkylthio C
1-4 alkyl, C1-4 alkylsulfonyl C1-4
Alkyl, C1-4 alkoxy C1-4 alkyl, alkoxy C1-4 alkoxy C1-4 alkyl, C1-4
Alkoxyl carbonyl C1-4 alkyl, carboxy C
1-4 alkyl, cyano C1-4 alkyl, C1-4 alkylcarbonyl C1-4 alkyl), nitro, C1
4 dialkylaminosulfonyl, C1-4 alkylcarbonyl, C1-4 alkoxycarbonyl, CONR ⁷ R
⁸ (R ⁷ and R ⁸ each independently represent hydrogen, C1 to C4 alkyl), carboxyl, hydroxy, cyano,
NR ⁹ R ¹⁰ (R ⁹ and R ¹⁰ are independently hydrogen, C 1
~ 4 alkyl, C1-4 alkoxy C1-4 alkyl,
C1-4 alkoxy, C1-4 alkylcarbonylamino), C1-4 alkylamide, pyridyloxy (which may be substituted with halogen, C1-4 alkyl, C1-4 haloalkyl) and the like.

The compound of the present invention can be produced by the following method.

[0009]

[Chemical 6]

(Wherein R ¹ , R ^{2 to} R ⁴ , n and A
Has the same meaning as described above, and Q means a leaving group such as halogen, alkylcarbonyloxy, alkoxycarbonyloxy and benzoyloxy. ) In the step, compound [Va] [Vb] is compound [I]
It can be obtained by using 1 mol each of I] and compound [IV] or one of them in excess, and reacting them in the presence of 1 mol or an excess of a base. The base used is KOH,
Alkali metal hydroxides such as NaOH, alkali metal carbonates, alkaline earth metal hydroxides, alkaline earth metal carbonates, tri (C ₁ -C ₆ alkyl) amines, pyridine, sodium phosphate, etc. As water, water, methylene chloride, chloroform, toluene, ethyl acetate, dimethylformamide, THF, dimethoxyethane, acetonitrile and the like are used. The reaction mixture is 0 until the reaction is complete.
Stir at -50 ° C. It can also be obtained by reacting in a two-phase system using a phase transfer catalyst such as a quaternary ammonium salt. The compounds [Va] and [Vb] can also be obtained by reacting the compound [II] and the compound R ¹ COOH [VI] with DCC. Solvents used in the reaction with DCC include methylene chloride, chloroform, toluene, ethyl acetate, dimethylformamide, T
HF, dimethoxyethane, acetonitrile and the like are used. The reaction mixture is -10 ° C to 50 ° C until the reaction is completed.
Stir at. The reaction mixture is worked up by conventional methods.
The rearrangement reaction of [Va], [Vb] to [I] is carried out in the presence of a cyano compound and a mild base. For example, 1
1 to 4 mol of a base, preferably 1 to 2 mol of a base, and 0.01 to 0.5 mol or more, preferably 0.05 to 0. mol of the above compound ([Va], [Vb]). React with 2 moles of cyanide. As the base used here, any of the above bases can be used. Also,
As the cyano compound, potassium cyanide, aton cyanhydrin, hydrogen cyanide, a polymer holding potassium cyanide, or the like is used. The reaction can be completed in a shorter time by adding a small amount of a phase transfer catalyst such as crown ether. The reaction temperature is room temperature to 80 ° C, preferably room temperature to 40 ° C. The solvent used is 1,
2-dichloroethane, toluene, acetonitrile, methylene chloride, ethyl acetate, dimethylformamide, methyl isobutyl ketone, THF, dimethoxyethane and the like.

The above-mentioned substituted benzoic acid chloride and benzoic acid can be produced according to known methods.

The cyclic dione body represented by the general formula [II] is
It can be manufactured according to the route shown below.

[0013]

[Chemical 7]

(In the formula, R ² , R ⁴ , R ¹² , A and n have the same meanings as described above, R ¹¹ represents C1-4 alkyl, and X represents halogen.) Cyclic aminocarboxylic acid ester [VII] The diester compound [IX] is obtained by reacting an acid halide [VIII] in the same mole or excess with 1 mole or in the presence of an excess base. The base used is KOH, NaO
Alkali metal hydroxides such as H, alkali metal carbonates, alkaline earth metal hydroxides, alkaline earth metal carbonates, tri (C ₁ -C ₆ alkyl) amines, pyridine, sodium phosphate, etc. As water, water, methylene chloride, chloroform, toluene, ethyl acetate, dimethylformamide, THF, dimethoxyethane, acetonitrile and the like are used. The reaction is carried out between −10 ° C. and the boiling point of the solvent used. The reaction product [IX] is obtained from the reaction mixture by a conventional treatment method. Next, diester [IX]
In the presence of an equimolar to 3-fold molar amount of an alkali metal alcoholate such as sodium ethylate or a metal hydride such as sodium hydride in an organic solvent between 0 ° C. and the boiling point of the solvent, and then an inorganic such as hydrochloric acid. The ester form [III '] is obtained by neutralizing with an acid. Examples of the solvent used in the reaction include alcohols such as ethanol and methanol, ethers such as THF and dimethoxyethane, hydrocarbons such as toluene and xylene, and DMF. The obtained ester form [III '] is heated in a solvent in the presence of water to produce a dione form [II'].
Is obtained. Examples of the solvent used in the reaction include methylene chloride, chloroform, toluene, ethyl acetate, dimethylformamide, THF, dioxane, dimethoxyethane, acetonitrile and the like. Also [III ′]
Gives [III] by the presence of a strong base such as LDA or nBuLi by an electrophilic reagent such as alkyl halide or alkyl disulfide. The ester form [III] is [III
In the same manner as in '], heating in a solvent in the presence of water gives a dione body [II]. The above cyclic-α-acetic acid esters are described in, for example, J. Org. Chem. , 27 , 1
39 (1962) and Tetrahedron Le
tt. , 29 , 819 (1988) and the like, and can be produced from β-amino acids.

[0015]

[Chemical 8]

Starting compounds [II], [III] and [V]
And the compound of the present invention has an optically active form, and further has a number of tautomeric forms, for example,

[0017]

[Chemical 9]

It may exist in the form of All such forms are included within the scope of the present invention.

When the compound [I] has a free hydroxyl group (*) among the above tautomers, a salt thereof, particularly an agro-horticulturally acceptable salt, is obtained from the compound. Enamine or its analogues, acylates, sulfonates,
Carbamates, ethers, thioethers, sulfoxides or sulfones and the like can be derived. Suitable agro-horticulturally acceptable salts include salts such as sodium, potassium, calcium and ammonium. Examples of ammonium salts include the formula: N ⁺ R ^a R ^b R ^c R ^d (wherein R ^a , R ^b , R ^c and R ^d are each independently substituted with hydrogen and optionally a hydroxy group, etc.). C
Examples thereof include salts with ions of _{1 to} C ₁₀ alkyl group). If any of ^Ra , ^Rb , ^Rc and ^Rd is an optionally substituted alkyl group, it is desirable that they contain from 1 to 4 carbon atoms.
Suitable enamines or analogs thereof are those wherein the OH moieties are each of the formula: --NR ^e R ^f , where R ^e and R ^f are each independently hydrogen or optionally substituted alkyl, for example having 1 to 6 carbon atoms. Group or an aryl group such as a phenyl group), halogen, S (O) _g R ^h (in the formula, R ^h
Is, for example, an optionally substituted alkyl or aryl group having 1 to 6 carbon atoms, for example a phenyl group, g
Represents 0 to 2. ) Is a compound that has been converted to.
Suitable acylate, ether or carbamate derivatives have OH moieties of the formula: -OCOR ¹ , -OR ^j , respectively.
Or a compound converted to -OCONR ^k R ^l (wherein R ¹ and R ^j have the same meaning as R ^h described above, and R ^k and R ¹ have the same meaning as R ^e described above). Is. These derivatives can be manufactured by a conventional method. After the completion of the reaction, the target product can be obtained by performing a usual post-treatment. The structure of the compound of the present invention was determined by IR, NMR and MS.

[0020]

EXAMPLES Next, the compounds of the present invention will be described in more detail with reference to examples.

Example 1 6-Ethoxycarbonyl-1,2,3,6,8,8a-
Hexahydroindolizine-5,7-dione

[0022]

[Chemical 10]

1.28 g of sodium metal and 3 ethanol
12.6 g of ethyl N-ethoxycarbonylacetylpyrrolidine-2-acetate is added to sodium ethylate synthesized from 5 ml, and the mixture is heated under reflux for 2 hours. After cooling, the mixture was extracted with a 5% aqueous sodium hydroxide solution, the aqueous layer was acidified with 2N hydrochloric acid under cooling, and extracted three times with chloroform. The chloroform layer was dried over magnesium sulfate and concentrated to obtain 10.4 g of the desired product. NMR δ (ppm) 1.4 (t, 3H), 1.7
(M, 1H), 2.0 (m, 1H), 2.3 (m, 1)
H), 2.6 (m, 2H), 3.5 (m, 1H), 3.
7 (m, 2H), 4.4 (q, 2H), 13.9 (s,
1H)

Example 2 1,2,3,6,8,8a-hexahydroindolizine-5,7-dione

[0025]

[Chemical 11]

6-ethoxycarbonyl-1, 2, 3,
10.8 g of 6,8,8a-hexahydroindolizine-5,7-dione was dissolved in 70 ml of acetonitrile, 7 ml of water was added, and the mixture was heated under reflux for 1 hour. After cooling, the solvent was concentrated under reduced pressure, the residue was dissolved in 5% aqueous sodium hydroxide solution, and washed with chloroform. The aqueous layer was acidified with 2N hydrochloric acid under ice cooling and extracted with chloroform three times. The chloroform layer was dried over magnesium sulfate and concentrated to obtain 4.4 g of the desired product. NMR δ (ppm) 1.7 (m, 1H), 1.9
(M, 1H), 2.1 (m, 1H), 2.3 (dd, 1)
H), 2.4 (m, 1H), 2.85 (dd, 1H),
3.25 (q, 2H), 3.6 (m, 2H), 3.9
(M, 1H)

Example 3 6- (3-Methoxy-2-methyl-4-methylsulfonylbenzoyl) -1,2,3,6,8,8a-hexahydroindoline-5,7-dione (Compound No. 65)

[0028]

[Chemical 12]

0.5 g of 1,2,3,6,8,8a-hexahydroindolizine-5,7-dione was dissolved in 3 ml of dichloromethane, and 0.4 g of triethylamine was added under cooling.
Was added, and then 0.9 g of 3-methoxy-2-methyl-4-methylsulfonylbenzoyl chloride was added, followed by stirring at room temperature for 2 hours. The reaction solution was first washed with an aqueous solution of sodium bicarbonate, then diluted hydrochloric acid and washed with water, and then the dichloromethane layer was dried over magnesium sulfate. The solvent was concentrated under reduced pressure to obtain an O-benzoyl compound, the O-benzoyl compound was dissolved in 5 ml of atonitrile, 0.7 g of triethylamine and 0.06 g of acetone cyanohydrin were added, and the mixture was stirred at room temperature for 20 hours. . Ice water and chloroform were added to the reaction solution, which was then extracted twice with a 5% aqueous sodium hydroxide solution. Then, the aqueous layer was acidified with 2N hydrochloric acid under ice cooling and extracted with chloroform three times. The chloroform layer was dried over magnesium sulfate, the solvent was distilled off, and the residue was purified by silica gel column chromatography (chloroform-methanol) to obtain 0.8 g of the desired product as crystals. Melting point 178-180 ° C

Reference Example 1 Ethyl N-ethoxycarbonyl-3-pyrrolidinone-
2-acetate dithioethylene ketal

[0031]

[Chemical 13]

45.9 g of ethyl N-ethoxycarbonyl-3-pyrrolidinone-2-acetate was dissolved in 450 ml of dichloromethane, and ethanedithiol 2 was added under cooling.
After adding 1.31 g, boron trifluoride ether complex was added dropwise under cooling. The reaction solution was stirred at room temperature for 1 hour and then heated and refluxed overnight. After cooling, the reaction solution was washed with water, the dichloromethane layer was dried over magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This product is purified by silica gel column chromatography to obtain the desired product 54.
7 g was obtained.

Reference Example 2 Ethyl N-ethoxycarbonylpyrrolidine-2-acetate

[0034]

[Chemical 14]

Ethyl N-ethoxycarbonyl-3-pyrrolidinone-2-acetate 39.4 g of dithioethylene ketal was dissolved in 800 ml of benzene and 2.03 g of 2,2'-azobisisobutyronitrile and tributyl hydride were dissolved in a stream of nitrogen. After adding 148.24 g of tin,
The mixture was heated under reflux for 9 hours. After cooling, the reaction solution was washed with water, the dichloromethane layer was dried over magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This product was purified by silica gel column chromatography to obtain 26.5 g of the desired product.

Reference Example 3 Ethyl N-ethoxycarbonylacetylpyrrolidine-
2-acetate

[0037]

[Chemical 15]

25.5 g of ethyl N-ethoxycarbonylpyrrolidine-2-acetate was added to 250 m of chloroform.
Iodotrimethylsilane 44.5 at room temperature
After adding 6 g, the mixture was stirred at room temperature for 6 days. The reaction solution was concentrated under reduced pressure, 250 ml of dichloromethane was added to the concentrated residue, and 13.5 g of triethylamine and then 20.11 g of ethylmalonyl chloride were added dropwise under cooling. The reaction solution was stirred at room temperature for 7 hours. After completion of the reaction, the reaction solution was washed with water, the dichloromethane layer was dried over magnesium sulfate and then concentrated under reduced pressure to obtain a crude product. This product was purified by silica gel column chromatography to obtain 12.1 g of the desired product.

Representative examples of the compounds of the present invention, including the above examples, are shown in Table 1.

[0040]

[Table 1001]

[0041]

[Table 1002]

[0042]

[Table 1003]

[0043]

[Table 1004]

[0044]

[Table 1005]

[0045]

[Table 1006]

[0046]

[Table 1007]

[0047]

[Table 100]

[0048]

[Table 1009]

The compound of the present invention exhibits high herbicidal activity under both upland conditions and both soil treatment and foliage treatment. In particular, a compound which shows high efficacy against various field weeds such as crabgrass, chinensis, cyperaceae, scabbard, croaker, etc. by foliar spraying treatment, and has selectivity for crops such as corn, wheat and soybean is also included. In addition, the compound of the present invention also includes a compound having a growth inhibitory action on useful plants such as crops, ornamental plants and fruit trees. Further, the compound of the present invention is
It also contains compounds that have excellent herbicidal activity against weeds such as paddy field weeds such as Nobie, Tamagawai, Omodaka and Firefly, and show selectivity for rice. Furthermore, the compound of the present invention can be applied to control weeds in orchards, lawns, track ends, vacant lots, and the like.

[0050]

Means for Solving the Problem-Herbicides The herbicides of the present invention contain, as an active ingredient, one or more of the compounds represented by the above general formula [I] or salts thereof,
It has the same form as ordinary pesticides. That is, the active ingredient compound is generally used by formulating it in the form of a wettable powder, an emulsion, granules, a water solvent, a flowable agent, etc. by mixing an appropriate amount with a carrier. Examples of the solid carrier include talc, white carbon (silica), bentonite, clay, diatomaceous earth, etc., and examples of the liquid carrier include water, alcohol, benzene, xylene, kerosene, mineral oil, cyclohexane, cyclohexanone, dimethylformamide and the like. . In these formulations, a surfactant can be added if necessary to take a uniform and stable form.

The concentration of the active ingredient in the herbicide of the present invention varies depending on the form of the above-mentioned preparation. For example, in a wettable powder, the concentration is 5 to 70%, preferably 10 to 30%. : In the emulsion, 3 to 70%, preferably 5 to 20%; in the granule, 0.01 to 30%, preferably 0.05 to 10%. The wettable powder and emulsion thus obtained are diluted with water to a predetermined concentration to give a suspension or emulsion, and the granules are sprayed or mixed as they are before or after germination of weeds. .
In actual application of the herbicide of the present invention, an appropriate amount of 0.1 g or more of the active ingredient is applied per 10 ares.

Further, the herbicide of the present invention can be used by mixing with known fungicides, insecticides, acaricides, herbicides, plant growth regulators and the like. In particular, it is possible to reduce the dose used by mixing with a herbicide. or,
Not only can labor saving be achieved, but a higher effect can be expected due to the synergistic action of the mixed drugs. In that case, a combination with a plurality of known herbicides is also possible. Suitable agents to be used in combination with the herbicide of the present invention include bench carb, molinate, carbamate herbicides such as dimepiperate, thiocarbamate herbicides, butachlor, pretilachlor, acid amide herbicides such as mefenacet, clomethoxynil, bifenox and the like. Diphenyl ether herbicides, triazine herbicides such as atrazine and cyanazine, sulfonylurea herbicides such as chlorsulfuron and sulfometuron-methyl, phenoxyalkanecarboxylic herbicides such as MCP and MCPB, and phenoxyphenoxypropione such as diclofop-methyl. Acid herbicides,
Pyridyloxyphenoxypropionic acid-based herbicides such as fluazifop-butyl, benzoylaminopropionic acid-based herbicides such as benzoylpropethyl, and furanpropethyl, imidazolinone-based herbicides such as imazaquin, and others, piperofos, dimuron, bentazone, Daifenzo coat, naproanilide, HW-52 (4-ethoxymethoxybenz-2,3-dichloroanilide), triazophenamide, quinclorac, and cyclohexanedione-based herbicides such as setoxydim and alloxidim-sodium. Etc. It is also possible to add vegetable oils and oil concentrates to these combinations.

[0053]

[Examples] -Herbicides Next, some production examples of the herbicides of the present invention will be shown. The active ingredient compounds, additives and addition ratios are not limited to these examples, and can be varied within a wide range. is there.

Example 4 Hydrate Compound of the present invention 20 parts White carbon 20 parts Diatomaceous earth 52 parts Sodium alkyl sulfate 8 parts The above components were uniformly mixed and finely ground to obtain a wettable powder containing 20% of the active ingredient. .

Example 5 Emulsion Compound of the present invention 20 parts Xylene 55 parts Dimethylformamide 15 parts Polyoxyethylene phenyl ether 10 parts The above components were mixed and dissolved to obtain an emulsion containing 20% of the active ingredient.

Example 6 Granules Compound of the present invention 5 parts Talc 40 parts Clay 38 parts Bentonite 10 parts Sodium alkyl sulfate 7 parts The above components are uniformly mixed and finely pulverized to give a diameter of 0.5 to 1.
Granules having a particle size of 0 mm were obtained to obtain granules containing 5% of the active ingredient.

[0057]

Next, test examples relating to the effects of the herbicide of the present invention will be shown. Test Example 1 Foliar spray treatment A 200 cm ² pot was filled with soil, and various larvae of crabgrass, chinensis velvetleaf, Amaranthus communis, and Cyperaceae were sown on the surface layer, lightly covered with soil, and then grown in a greenhouse. When each weed grows to a height of 5 to 10 cm, an emulsion of each compound to be tested is diluted with water to prepare a 1000 ppm chemical solution at a rate of 100 liter / 10a (100 g per 10 a).
It was sprayed on the foliage of weeds with a small sprayer. After 3 weeks, the herbicidal effect of weeds was investigated according to the following criteria, and the results are shown in Table 2 below.

Survey Standards Weeding rate Weeding index 0% 0 20-29% 2 40-49% 4 60-69% 6 80-89% 8 100% 10 Also, numerical values of 1, 3, 5, 7, 9 Indicates values intermediate between 0 and 2, 2 and 4, 4 and 6, 6 and 8, and 8 and 10, respectively.

[0059]

[Equation 1]

[0060]

[Table 2]

Front page continued (72) Inventor Kazuyuki Tomita 345 Yanagicho, Takada, Odawara, Kanagawa Japan Odawara Research Institute, Nippon Soda Co., Ltd. (72) Akihiro Takahashi, 345, Yanagicho, Takada, Odawara, Kanagawa Nihon Soda Co., Ltd. In-house (72) Inventor Takashi Kawana 345 Yanagimachi, Takada, Odawara, Kanagawa Nihon Soda Co., Ltd.

Claims (4)

[Claims] 1. A compound represented by the general formula [I]: (In the formula, R ¹ represents optionally substituted phenyl, optionally substituted pyridine, optionally substituted aralkyl, and R ² and R ³ are each independently hydrogen, halogen,
C1-4 alkyl, C1-4 alkoxy C1-4 alkyl, C1-4 alkoxy, C1-4 alkylthio, C1
~ 4 alkylsulfinyl, C1_4 alkylsulfonyl, C1_4 alkoxycarbonyl, carboxyl, and n is 0 or 1. R ² and R ³ may together represent a C2-4 alkylene chain. R
⁴ represents hydrogen or C1-4 alkyl. A is C1-4
Represents an optionally substituted alkylene chain, and as the substituent, C1-4 alkyl, C1-4 alkoxy, C1-4 alkyl, C1-4 alkoxy, C1-4 alkylthio,
C1-4 alkylsulfinyl, C1-4 alkylsulfonyl, halogen, oxo and thioxo. ) A substituted fused piperidinedione derivative represented by the formula) or a salt thereof. 2. A compound represented by the general formula [II]: (In the formula, R ² , R ³ , R ⁴ , A and n have the same meanings as described above.) A substituted fused piperidinedione derivative represented by the above formula. 3. A compound represented by the general formula [III]: (In the formula, R ² , R ³ , R ⁴ , A, and n have the same meanings as described above, and R ¹² represents C1-4 alkyl.) A substituted fused piperidinedione derivative. 4. A compound represented by the general formula [I]: (Wherein R ¹ , R ² , R ³ , R ⁴ , A and n have the same meanings as described above) or one or more of salts thereof as an active ingredient. A herbicide characterized in that