Heterocyclic Cyclohexanedione Derivative, Production Thereof, and Herbicide

This application is a 35 U.S.C. .sctn.371 National Stage application of PCT/JP92/00877 filed on Jul. 8, 1992.

1. Field of the Invention

The present invention relates to a heterocyclic cyclohexanedione derivative, a process for production thereof, and a herbicide comprising the same.

2. Background of the Invention

In agricultural and horticultural crop farming, many herbicides have been used for weed control which requires extraordinary labours. However, there have been several cases which caused phytotoxicity problems and environmental pollution such as residue problems therefore, it is required to develop a new chemical entity which can provide firm effectiveness with a lower dosage and can be used safely is in a high demand.

It is an object of the present invention to provide a herbicide which can be synthesized advantageously in a industrial scale and having a property such as high effectiveness at lower dosage, highly safe, and high selectivity on crops.

The present invention is directed to a heterocyclic cyclohexanedione derivative represented by the general formula I!; ##STR2## wherein R.sup.1 is optionally substituted lower alkyl, optionally substituted cycloalkyl, optionally substituted phenyl or optionally substituted heterocyclic ring; R.sup.2, R.sup.3, R.sup.4 and R.sup.5 may be the same or different from one another and each represents hydrogen or lower alkyl; R.sup.6 is hydrogen; R.sup.7 is OR.sup.8 wherein R.sup.8 is hydrogen, lower alkyl, aralkyl, lower acyl, alkylsulfonyl, or arylsulfonyl; or R.sup.6 and R.sup.7 are combined together to represent a single bond; X is oxygen, sulfur or N--R.sup.9 wherein R.sup.9 is hydrogen, lower alkyl, optionally substituted aralkyl, optionally substituted cycloalkyl, optionally substituted phenyl or optionally substituted heterocyclic ring, or a salt thereof, a process for producing the same, and a herbicide comprising the same.

The substituents such as lower alkyl, cycloalkyl, phenyl and heterocyclic ring for R.sup.1 may be the same or different from one another and each independently represents halogen, hydroxy, nitro, cyano, alkyl except when R.sup.1 is lower alkyl, alkenyl, haloalkyl except when R.sup.1 is lower alkyl, alkoxyalkyl except when R.sup.1 is lower alkyl, alkoxyalkoxyalkyl except when R.sup.1 is lower alkyl, alkoxycarbonylalkyl except when R.sup.1 is lower alkyl, haloalkenyl, alkoxy, alkenyloxy, alkynyloxy, haloalkoxy, haloalkenyloxy, alkoxyalkoxy, alkylthioalkoxy, alkylthio, alkenylthio, alkynylthio, haloalkylthio, haloalkenylthio, monoalkylamino, dialkylamino, alkoxyakylthio, alkylthioalkylthio, alkoxycarbonyl, alkylcarbonylalkoxy, alkylcarbonyl, alkoxyamino, alkylsulfonyl, alkenylsulfonyl, alkynylsulfonyl, alkoxyalkylsulfonyl, alkylthioalkylsulfonyl, alkylsulfonylalkylsulfonyl, haloalkylsulfonyl, alkoxycarbonylalkylthio, alkylsulfinylalkoxycarbonylalkylsulfinyl, alkoxycarbonylalkylsulfonyl, alkylamide, aralkyloxy, optionally substituted phenyl, optionally substituted aralkyl, optionally substituted heterocyclic ring, or alkyl substituted by optionally substituted heterocyclic ring.

Heterocyclic ring represents pyridyl, pyrimidyl, thienyl, furyl, pirazolyl, pyrrolyl, imidazolyl, pyridazinyl, pirazinyl, indolyl, or the like.

The compounds of the present invention can be produced according to the following process. ##STR3## wherein R.sup.1 through R.sup.5 and X are as defined above, Q is a leaving group which represents halogen, alkylsulfonate, arylsulfonate, or the like.

In the process as illustrated above, compound I'! is obtained by reacting a compound II! in a solvent and in the presence of 2 mol or excessive concentration of a base for 30 minutes to several 10 hours at the temperature of from -20.degree. C. to a boiling point of a solvent used, preferably from 0.degree. C. to 50.degree. C.

For the base described above, alkali metal hydroxides such as KOH and NaOH, alkaline earth metal hydroxides, tri(C.sub.1 -C.sub.6 alkyl)amine, pyridine, DBU, t-BuOK, triton B, sodium carbonate, sodium phosphate and the like can be used. For the solvent described above, water, alcohol, methylene chloride, benzene, toluene, ethyl acetate, dimethylformamide, THF, dimethoxyethane, acetonitrile and the like can be used by alone or in the mixture.

The compounds represented by the general formula I! can be produced according to the following process. ##STR4##

Compound V! is obtained by reacting each 1 mol of a compound III! and IV!, wherein Z is halogen, alkylcarbonyloxy, alkoxycarbonyloxy or benzoyloxy, in the presence of 1 mol or excessive concentration of the base.

For the base to be used, alkali metal hydroxides such as KOH and NaOH, alkaline earth metal hydroxides, tri(C.sub.1 -C.sub.6 alkyl)amine, pyridine, sodium carbonate, sodium phosphate and the like can be used. For the solvent to be used, water, methylene chloride, chloroform, toluene, ethyl acetate, dimethylformamide, THF, dimethoxyethane, acetonitrile and the like can be used.

The mixture for the reaction is stirred at from 0.degree. C. to 50.degree. C. till the completion of the reaction. Alternatively, the mixture for the reaction can be reacted in a bilayer solvent by using a phase-transfer catalyst such as BTEAC.

Compound V! is also obtained by reacting the compound III! and a compound, R.sup.1 COOH VI! with DCC.

For a solvent used in the reaction with DCC, methylene chloride, toluene, ethyl acetate, dimethoxyethane, acetonitrile or the like can be used. The mixture is reacted in stirring at 0.degree. C. to 50.degree. C. till the completion of the reaction. The mixture reacted is treated according to a customary method.

The transition reaction for the production of the compound of the present invention is carried out in the presence of a cyano compound and a mild base. For example, 1 mol of the compound V! described above is reacted with 1 to 4 mol, preferably 2 mol of the base and 0.01 to 0.5 mol, preferably 0.05 to 0.1 mol of the cyano compound. For the base to be used in the reaction, any bases described above can be usable. For the cyano compound to be used in the reaction, polymers which retains potassium cyanide, acetonecyanohydrine, hydrogen cyanide, and potassium cyanide can be used.

By adding small amount of a phase-transfer catalyst such as crown ether, the reaction can be completed in a short time. This reaction is conducted at the temperature lower than 80.degree. C., preferably at the range from 20.degree. C. to 40.degree. C. The solvents to be used can be selected among 1,2-dichloroethane, toluene, acetonitrile, methylene chloride, ethyl acetate, dimethylformamide, methylisobutylketone, THF, dimethoxyethane and the like.

The compound I! can be obtained from the reaction of the compound III! with the compound VII! in the presence of a base, and a Lewis acid if necessary. ##STR5##

As the base to be used in the reaction, metal hydroxides such as KOH and NaOH, alkali metal hydroxides, tri(C.sub.1 -C.sub.6 alkyl)amine, pyridine, sodium carbonate, sodium phosphate, or the like can be exemplified. For the Lewis acid suitable in this reaction, zinc chloride and ammonium trichloride can be exemplified.

The reaction is conducted at an adequate temperature in a range from -20.degree. C. to 40.degree. C. in an organic solvent such as acetonitrile and methylene chloride.

It is preferable to use both of zinc chloride and a base in an amount little excessive than the amount of the compound III!.

The compound represented by the general formula II! can also led from the compound represented by the general formula VIII!. ##STR6## wherein R.sup.7' is hydroxy, lower alkoxy, aralkyloxy or acetoxy.

For example, the compound represented by the general formula VIII! wherein R.sup.7' is other than OH can be produced from halogenated acid such as hydrobromic acid-acetic acid solution or by the hydrogenolysis of the compound represented by the general formula VIII! wherein R.sup.7' is other than OH, and the hydrolysis thereof, if necessary. The compound represented by the general formula II! can be obtained from the halogenation, alkylsulfonation or arylsulfonation of the compound represented by the general formula VIII! wherein R.sup.7' is OH according to the commonly-known methods.

The compound represented by the general formula III! to be used in the reaction can be synthesized according to the methods disclosed in Syn. Commun., 18, 949-963(1988); Liebigs Ann. Chem., 1975, 2261-2278; J. Heterocyclic Chem., 15, 1153-1158(1978) and Monatsh Chem., 111, 1175-1184(1980), 113, 1283-1297(1982).

The raw material compounds and the compound I! of the present invention contain optically active substances and which can exist in forms of many tautomers as shown in the following reaction formula. All of these optically active substances and the tautomers are included in the scope of the present invention. ##STR7##

When the compound I! contains free hydroxyl group in the reaction formula described above, the salts, particularly agriculturally and horticulturally acceptable salts, enamine or the analogs thereof, acylates, sulfonates, carbamates, or ethers can be induced from the compound I!.

For the agriculturally and horticulturally acceptable salts adequate for the above reaction formula, sodium salts, potassium salts, calcium salts and ammonium salts are exemplified.

For examples of the ammonium salts described above, the salts of N.sup.+ R.sup.a R.sup.b R.sup.c R.sup.d wherein R.sup.a, R.sup.b, R.sup.c and R.sup.d are each independently selected from C.sub.1 -C.sub.10 alkyls substituted by hydrogen, or occasionally hydroxy, can be exemplified. If any of R.sup.a, R.sup.b, R.sup.c and R.sup.d is alkyl occasionally substituted, the one which contains 1 to 4 carbon atoms therein are preferable.

The adequate enamines or the analogs thereof are the one of which OH portion is independently converted to --NR.sup.e R.sup.f wherein R.sup.e is alkyl or aryl such as phenyl which contains 1 to 6 carbon atoms and is occasionally substituted; R.sup.f is hydrogen or, alkyl or aryl such as phenyl which contains 1 to 6 carbon atoms and is occasionally substituted, halogen or SR.sup.g wherein R.sup.g is the same as R.sup.e described above. An adequate acylate or ether derivative is the one of which OH portion is converted to --OC(O)NR.sup.i R.sup.g wherein R.sup.i and R.sup.g are each independently hydrogen or the same as R.sup.e described above. These derivatives can be produced according to a customary method.

After the completion of the reaction, the objective products can be obtained through a customary post-treatment procedure. The chemical structures of the compounds of the present invention are determined according to IR, NMR, MS, etc.

Now, the compounds according to the present invention are further explained in detail with referring to the following Examples.

To 10 ml of ethanol was dissolved 0.95 g (2.3 mmole) of 6-mesyloxymethyl-3-(4-chloro-2-nitrobenzoyl)-tetrahydropyran-2,4-dione, and was further added 3.3 g (5.8 mmole) of 7% aqueous solution of sodium hydrate at room temperature, then allowed for stirring for 16 hours. After the completion of the reaction, the mixture was poured into ice water, acidified with diluted hydrochloric acid to extract it with chloroform. The organic solvent layer extracted was washed with saturated brine, dried with magnesium sulfate, then the solvent was distilled. To the residue was added methanol, then it is crystallized to obtain 0.20 g of the objective product in whitish crystals. The melting point thereof was from 137.degree. to 139.degree. C.

To 15 ml of benzene was dissolved 0.70 g (1.5 mmole) of 6-iodomethyl-3-(2,3-dimethyl-4-methylsulfonylbenzoyl)-tetrahydropyran-2,4- dione, and 0.57 g (3.8 mmole) of DBU was added thereto at room temperature, then stirred it for 2 days. After the completion of the reaction, distilled benzene from the solution, and the residue was added with ice water, acidified with diluted hydrochloric acid, and extracted with chloroform. The organic solvent layer extracted was washed with saturated brine, dried with magnesium sulfate, then distilled the solvent therein. The residue was purified by silica gel column chromatography (chloroform) to obtain 0.35 g of the objective product in whitish crystals. The melting point thereof was from 0.degree. C. to 2.degree. C.

To 10 ml of ethanol was dissolved 1.30 g (3.1 mmole) of 6-mesyloxymethyl-3-(4-chloro-2-nitrobenzoyl)-1-methylpiperidine-2,4-dione, and 3.4 g (9.3 mmole) of 10% aqueous solution of sodium hydrate was added thereto at room temperature, then stirred it for 4 hours. After the completion of the reaction, the mixture was poured into ice water, acidified with diluted hydrochloric acid, and extracted with chloroform. The organic solvent layer extracted was washed with saturated brine, dried with magnesium sulfate, then distilled the solvent therein. The residue was purified by silica gel column chromatography (chloroform), then obtained 0.30 g of the objective product in pale yellowish crystals. The melting point thereof was from 145.degree. C. to 146.degree. C.

To 20 ml of methylene chloride were dissolved 2.00 g (8.6 mmole) of 6-benzyloxymethyltetrahydropyran-2,4-dione and 1.01 g (10.0 mmole) of triethylamine, and 1.88 g (8.6 mmole) of 4-chloro-2-nitrobenzoylchloride was added thereto at room temperature, then stirred the mixture for 30 minutes. The solution for the reaction was washed with diluted hydrochloric acid, water and saturated brine respectively in turn, the organic solvent layer thereof was dried with magnesium sulfate, then distilled the solvent to obtain 4.0 g of o-benzoyl compound. The o-benzoyl compound was dissolved into 30 ml of acetonitrile, added with 2.02 g (20.0 mmole) of triethylamine and 0.27 g (3.2 mmole) of acetonecyanohydrine at room temperature, and stirred the mixture for 16 hours. After the completion of the reaction, diluted hydrochloric acid was added to the resulting product, which is then extracted with chloroform. The organic solvent layer extracted was washed with saturated brine, dried with magnesium sulfate, then the solvent was distilled therefrom. The residue was purified by silica gel column chromatography (chloroform) to obtain 2.40 g of objective product in a state of sticky oil.

To 7.7 ml of 25% acetic acid solution of hydrobromic acid was dissolved 2.40 g (5.7 mmole) of 6-benzyloxymethyl-3-(4-chloro-2-nitrobenzoyl)tetrahydropyran-2,4-dione, then this solution was reacted at room temperature for 5 hours. After the completion of the reaction, the mixture was poured into ice water, then extracted with chloroform. The organic solvent layer extracted was washed with water and saturated brine in turn, dried with magnesium sulfate, then the solvent was distilled therefrom. The residue obtained was purified by silica gel column chromatography to obtain 1.50 g of the objective product in a state of orange-coloured sticky oil.

To 10 ml of ethanol was dissolved 1.50 g (4.1 mmole) of 6-acetoxymethyl-3-(4-chloro-2-nitrobenzoyl)-tetrahydropyran-2,4-dione, then 8.0 ml of 1N aqueous solution of sodium hydroxide was added thereto to react for 1 hour at room temperature. The solution for the reaction was poured into ice water, acidified with diluted hydrochloric acid, then extracted with chloroform. The organic solvent layer extracted was washed with water and saturated brine in turn, dried with magnesium sulfate, and the solvent therein was distilled. The resulting crystals were washed with methanol, then 0.90 g of the objective product was obtained in whitish crystals. The melting point thereof was from 135.degree. to 137.degree. C.

To 20 ml of methylene chloride was dissolved 1.27 g (3.9 mmole) of 6-hydroxymethyl-3-(4-chloro-2-nitrobenzoyl)-tetrahydropyran-2,4-dione and 1.20 g (11.6 mmole) of triethylamine, then 1.00 g (5.8 mmole) of methanesulfonate anhydride was added thereto, then the mixture was reacted for 2 hour at room temperature. After the completion of the reaction, the reacted product was poured into ice water, acidified with diluted hydrochloric acid, then the organic solvent layer thereof was washed with water and saturated brine in turn, dried with magnesiun sulfate. The solvent therein was distilled to obtain 1.55 g of the objective product in whitish crystals. The representative examples including the products obtained in the examples described above are shown in Tables 1 through 4.

The compounds of the present invention show high herbicidal activity in either method of soil application or foliar application in upland crop farming condition. When the compounds are applied particularly by foliar application, those show high herbicidal activity against various upland crop weeds such as crabgrass, rice flatsedge, Velvet leaf, and redroot pigweed, and some of those compounds show selectivity on crops such as maize, cereals, soybean, etc.

In the compounds of the present invention, the compounds which have growth regulating action on crops, ornamental plants, fruit trees, etc. are included.

The compounds of the present invention have excellent herbicidal activity on weeds in paddy rice fields such as barnyardgrass, smallflower umbrellaplant, arrowhead, and Japanese bulrush, and the compounds having selectivity on rice are also included thereto.

Furthermore, the compounds of the present invention can be applied for weed control in the fields of fruit trees, turf, railway sides, vacant grounds, etc.

The herbicides according to the present invention comprise 1 or more compounds represented by the general formula I! described above as their active ingredients and is formulated in the same manner as done for ordinary formulation of agricultural chemicals. More particularly, an adequate amount of the compounds to be used as an active ingredient are generally mixed with carrier to formulate wettable powders, emulsifiable concentrates, granules, water soluble powders, flowables, etc. for practical uses. For the solid carriers, talc, white carbon (silica), bentonite, clay, diatomaceous earth and the like can be exemplified. For the liquid carriers, water, alcohols, benzene, kerosine, mineral oils, cyclohexane, cyclohexanone, dimethylformamide and the like can be exemplified. In these formulations, surface active agents can be added thereto for improving the uniformity and stability thereof, if necessary.

The content of the active ingredients in the formulation of the herbicides of the present invention can be adjusted depending upon the type of the formulation described above, however, those are normally 5 to 70%, preferably 10 to 30% for the wettable powders; 3 to 70%, preferably 5 to 20% for the emulsifiable concentrates; 0.01 to 30%, preferably 0.05 to 10% for the granules.

The wettable powder and the emulsifiable concentrate obtained as described above are applied in a form of either suspension or emulsion after diluting with water to a certain concentration, and the granules is applied in a form as it is by spraying to soil or incorporating with soil at either before or after weed germination. In a case of practical application of the formulations described above, an adequate amount more than 1 g/10 are based on the active ingredient is applied to the objective weeds or soil.

In addition, the compounds of the present invention can be used in a mixture with known fungicides, insecticides, acaricides, herbicides, plant growth regulators, etc. In particular, the mixing with other herbicides can reduce a required dosage for each herbicides. Furthermore, such mixing of herbicides may give not only less labour requirement but also higher herbicidal activity if a synergistic action is obtained with such combination. Naturally, the combination with plural known herbicides is also allowable. The herbicides suitable to mix with the compounds of the present invention include carbamate or thiocarbamate herbicides, such as benthiocarb, molinate, and MY-93 S-(2,2-dimethylbenzyl)-1-piperidinecarbothioate!; acid amine herbicides, such as butachlor, pretilachlor, and mefenacet; diphenylether herbicides, such as chlomethoxynil and bifenox; triazine herbicides, such as atrazine and cycnazine; sulfonylurea herbicides, such as chlorsulfuron and sulfometuronmethyl; phenoxylalkane carboxylate herbicides, such as MCP and MCPB; phenoxypropionic acid herbicides, such as dichlofop-methyl; pyridyloxyphenoxypropionic acid herbicides, such as fluazifop-butyl; benzoylaminopropionic acid herbicides, such as benzoylprop-ethyl and flamprop-ethyl; and others such as piperophos, dymron, bentazon, difenzoquat, naproanilide, HW-52 (4-ethoxymethoxybenz-2,3-dichloroanilide), KNW-242 1-(3-methylphenyl)-5-phenyl-1H- 1,2,4-triazole-3-carboxamide!, quinclorac (3,7-dichloro-8-quinolinecarboxylic acid); and cyclohexanedione herbicides such as sethoxydim and alloxydim-sodium.

The addition of vegetable oils or oil concentrate to the above mixture is also allowable.

Now, the examples for the formulation prepared for the compounds of the present invention are described below, however, active ingredients, additives, and a portion of addition applicable to the formulations shall not be limited to the ones indicated in the examples, and it is allowable to modify in a wide range.

All the elements above are homogeneously mixed and micronized to obtain a wettable powder containing 20% active ingredient.

All the elements above are mixed and dissolved to obtain an emulsifiable concentrate containing 20% active ingredient.

All the elements above are homogeneously mixed and micronized, then granulated to granules having a diameter of from 0.5 to 1.0 mm to obtain the granules containing 5% active ingredient.

Now, test examples on the herbicidal activity of a compound of the present invention are shown below.

A pot having a surface area of 200 cm.sup.2 was filled with soil, then the respective seeds of crabgrass, giant foxtail, rice flatsedge, and velvet leaf were planted at upper layer of the soil, lightly covered with soil and grown in a greenhouse. When the weeds grew to 5 to 10 cm in height, the emulsion of the emulsifiable concentrate of each test compound adjusted to a concentration of 1,000 ppm by diluting with water were sprayed at a volume 100 liter/10 are (equivalent to 100 g a.i./10 are) to the foliage with small volume sprayer. After 3 weeks, the herbicidal activity of each compound was assessed in accordance with the criteria as shown below. The results shown in Table 5.

The values of 1, 3, 5, 7 or 9 indicates the intermediate activities of between 0 and 2, 2 and 4, 4 and 6, 6 and 8, or 8 and 10, respectively.

Weeds killed (%)= (Fresh weight of foliage of the weed untreated-Fresh weight of foliage of the weed in treated).div.Fresh weight of foliage of the weed untreated!.times.100

Seeds of crabgrass, giant foxtail, velvet leaf, redroot pigweed and rice flatsedge were planted in a plastic pot (250cm.sup.2 surface) containing upland field soil, then covered with soil in a thickness of 0.5 cm. On next day, the dilution of the wettable powder described in the Example 8 was uniformly sprayed over the surface of the soil so as to apply the active ingredient at the rate of 100 g/10 are. After 20 days, the assessment on the herbicidal activities of each compound was conducted in accordance with the criteria described in the Test Example 1. The results were shown in Table 6.