Substituted Pyrazoles

The present invention relates to new and valuable substituted pyrazoles, herbicides containing them, and their use as herbicides.

It is known (German Laid-Open Application DOS 2,260,485) to use 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate as herbicide. However, its action is poor.

We have now found that substituted pyrazoles of the formula ##STR1## where R.sup.1 denotes hydrogen, alkyl, cycloalkyl, aralkyl, substituted or unsubstituted phenyl, or acyl of the formula ##STR2## R.sup.6 denoting hydrogen, substituted or unsubstituted alkyl, alkoxy, phenoxy or phenyl, and R.sup.7 and R.sup.8 being identical or different and each denoting hydrogen, alkyl, or substituted or unsubstituted phenyl or alkynyl, R.sup.2 denotes substituted or unsubstituted alkyl, cycloalkyl, substituted or unsubstituted phenyl, or a heterocyclic radical having oxygen, nitrogen or sulfur atoms in the ring, R.sup.3 denotes hydrogen, chloro, bromo, or lower alkyl, and R.sup.4 denotes the radicals -S-R.sup.5, -SO-R.sup.5 or -SO.sub.2 -R.sup.5, R.sup.5 denoting alkyl, cycloalkyl, aralkyl, substituted or unsubstituted phenyl, or a heterocyclic radical having oxygen, nitrogen or sulfur atoms in the ring, are valuable herbicidally active compounds.

Preferred compounds are those in whose formulae R.sup.1 is hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclohexyl, benzyl, phenyl, 2-chlorophenyl, 2-fluorophenyl, 4-fluorophenyl, 3-trifluoromethylphenyl, 4-trifluoromethylphenyl, 4-chlorophenyl, 4-bromophenyl, 3-methylphenyl, 4-methylphenyl, 3,4-dichlorophenyl, 3,5-dichlorophenyl, 2-methyl-4-chlorophenyl, 3-chloro-4-methoxyphenyl, and -COR.sup.6 and ##STR3## R.sup.6 denoting hydrogen, methyl, ethyl, propyl, isopropyl, chloromethyl, dibromomethyl, trichloromethyl, 4-chlorophenoxymethyl, 2,4-dichlorophenoxymethyl, 2,4,5-trichlorophenoxymethyl, 2-methyl-4-chlorophenoxymethyl, 2,4-dichlorophenoxypropyl, methoxy, ethoxy and phenoxy, and R.sup.7 and R.sup.8 being identical or different and each denoting hydrogen, methyl, ethyl, propyl, isopropyl, isobutyl, phenyl, 3-chlorophenyl, 2,4-dimethylphenyl, 4-fluorophenyl, 3-trifluoromethylphenyl, 4-trifluoromethylphenyl, 2,4-dichlorophenyl, 3,4-dichlorophenyl, 3,5-dichlorophenyl and 3-chloro-4-methoxyphenyl; R.sup.2 is ethyl, propyl, isopropyl, chloromethyl, dibromomethyl, trifluoromethyl, .alpha.,.alpha.-dichloropropyl, cyclohexyl, cyclopentyl, phenyl, 2-chlorophenyl, 2-fluorophenyl, 4-bromophenyl, 4-fluorophenyl, 2,4-dichlorophenyl, 2,6-dichlorophenyl, 3,5-dichlorophenyl, 2-methyl-4-chlorophenyl, 3-methylphenyl, 2,4-dimethylphenyl, 3,5-dimethylphenyl, 3-chloro-4-methoxyphenyl, thienyl-(2) and 2,5-dimethylfuranyl-(3); R.sup.3 is hydrogen, chloro, bromo, methyl, ethyl, propyl and isopropyl; and R.sup.5 is methyl, ethyl, propyl, isopropyl, dodecyl, cyclohexyl, benzyl, phenylethyl, 4-chlorobenzyl, phenyl, 4-chlorophenyl, 4-fluorophenyl, 4-methoxyphenyl, benzothiazolyl-(2), benzimidazolyl-(2) and pyrimidyl-(2).

The new compounds may be prepared for instance by reacting a substituted vinyl ketone of the general formula ##STR4## with a hydrazine of the formula

r.sup.1 to R.sup.4 having the above meanings, X denoting oxygen or sulfur and Y denoting halogen or R.sup.4.

The compounds may also be prepared by reacting a 5-halopyrazole of the general formula ##STR5## with a mercaptan of the general formula

r.sup.1, r.sup.2, r.sup.3 and R.sup.5 having the preferred meanings and hal denoting chloro, bromo and iodo.

The route employing hydrazine and its derivatives is preferred.

The 5-halopyrazoles may be produced for instance by halogenating a 5-unsubstituted pyrazole, e.g., with bromine in glacial acetic acid.

Pyrazoles in which R.sup.4 is -SOR.sup.5 and -SO.sub.2 R.sup.5 may be prepared by oxidizing pyrazoles of the general formula ##STR6## R.sup.1, R.sup.2, R.sup.3 and R.sup.5 having the above meanings.

Finally, pyrazoles in which the hydrogen is replaced in the 1-position by alkyl, benzyl, -COR.sup.6 or ##STR7## may be prepared by reacting pyrazoles of the general formula ##STR8## with alkylating agents, acid chlorides, acid anhydrided or isocyanates. R.sup.2, R.sup.3, R.sup.4, R.sup.6, and R.sup.8 have the above meanings.

The preparation of the compounds of the invention is illustrated by the following examples.

70 parts (by weight) of .beta.,.beta.-di-(phenylthio)-vinyl phenyl ketone (A. E. Pohland and W. R. Benson, Chem. Rev., 66, 161 to 197, 1966) is mixed with 700 parts of dioxane and 20 parts of hydrazine hydrate for 3 hours at 90.degree. to 100.degree. C. After the dioxane has been distilled off, the oil which remains is mixed with 200 parts of a 10 wt% aqueous caustic solution. There is obtained 46 parts (91% of theory) of 3-phenyl-5-phenylthiopyrazole. After recrystallization from cyclohexane the compound melts at 99.degree. to 100.degree. C.

280 parts of .beta.-chloro-.beta.-(phenylthio)-vinyl phenyl ketone (A. G. Gudkova, Izv. Akad. SSSR, 1248 to 1254, 1962) is mixed with 55 parts of hydrazine hydrate and 42 parts of sodium hydroxide in 1,200 parts of methanol for 3 hours at 60.degree. to 65.degree. C. After 1,000 parts of water has been added, 240 parts (95.3% of theory) of 3-phenyl-5-phenylthiopyrazole is obtained; m.p.: 99.degree. to 100.degree. C (from cyclohexane).

13.7 parts of .beta.-chloro-.beta.-(phenylthio)-vinyl phenyl ketone is boiled for 3 hours with 5 parts of methyl hydrazine in 150 parts of dioxane. After the dioxane has been distilled off and 100 parts of water added to the residue there is obtained 11.5 parts (86.5% of theory) of 1-methyl-3-phenyl-5-phenylthiopyrazole. After recrystallization from ligroin, the compound melts at 61.degree. to 62.degree. C.

At 20.degree. to 25.degree. C, a few drops of concentrated sulfuric acid are added to a solution of 10 parts of 3-phenyl-5-phenylthiopyrazole in 100 parts of acetic anhydride. After 15 hours the solution is concentrated in vacuo and 50 parts of water is added to the residue. There is obtained 10.5 parts (90% of theory) of 1-acetyl-3-phenyl-5-phenylthiopyrazole; m.p.: 83.degree. to 84.5.degree. C (recrystallized from methanol).

Over a period of 30 minutes, a solution of 12.6 parts of 3-phenyl-5-phenylthiopyrazole in 50 parts of chloroform is added to a mixture of 20 parts of m-chlorobenzoic peracid (85%) in 150 parts of chloroform, the temperature rising from 25.degree. to 40.degree. C. The reaction solution is stirred with 20 parts of sodium bicarbonate slurried in 200 parts of water. The deacidified chloroform solution is separated and concentrated. There is obtained 13 parts (91.5% of theory) of 3-phenyl-5-phenylsulfone pyrazole; m.p.: 172.degree. to 174.degree. C (recrystallization from methanol).

At 25.degree. C, 8 parts of bromine is slowly added, with stirring, to a solution of 12.6 parts of 3-phenyl-5-phenylthiopyrazole in 150 parts of glacial acetic acid. After 12 hours, the solution is concentrated in vacuo and the residue treated with about 50 parts of water. There is obtained 16 parts (96.7% of theory) of 3-phenyl-4-bromo-5-phenylthiopyrazole; m.p.: 121.degree. to 122.degree. C (recrystallized from cyclohexane).

12.6 parts of 3-phenyl-5-phenylthiopyrazole, 100 parts of toluene and 6 parts of phenyl isocyanate are stirred for 12 hours at 20.degree. C. After the toluene has been distilled off, there is obtained 13 parts (70% of theory) of 1-(phenylcarbamoyl)-3-phenyl-5-phenylthiopyrazole; m.p.: 138.degree. to 139.5.degree. C (recrystallized from acetonitrile).

The following compounds were prepared analogously:

The new compositions have a strong herbicidal action and may therefore be used as weedkillers or for controlling the growth of unwanted plants. Whether the new active ingredients are used as total or selective agents depends in essence on the amount of ingredient used per unit area.

By weeds and unwanted plant growth are meant all monocotyledonous and dicotyledonous plants which grow in loci where they are not desired.

The agents according to the invention may therefore be used for controlling for instance Gramineae, such as

The herbicides according to the invention may be employed in cereal crops such as

The amount used of the agents according to the invention may vary and depends in essence on the type of effect to be achieved; it is generally from 0.1 to 15 (and more), preferably from 0.2 to 6, kg per hectare of active ingredient. The agents according to the invention may be used once or several times before or after planting, before sowing, and before, during or after emergence of the crop plants and unwanted plants.

Application may be effected for instance in the form of directly sprayable solutions, powders, suspensions, dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents, or granules by spraying, atomizing, dusting, broadcasting or watering. The forms of application depend entirely on the purpose for which the agents are being used; in any case they should ensure a fine distribution of the active ingredient.

For the preparation of solutions, emulsions, pastes and oil dispersions to be sprayed direct, mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils, etc. and oils of vegetable or aninmal origin, aliphatic, cyclic and aromatic hydrocarbons such as benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, chloroform, carbon tetrachloride, cyclohexanol, cyclohexanone, chlorobenzene, isophorone, etc., and strongly polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, water, etc. are suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastes, oil dispersions or wettable powders by adding water. To prepare emulsions, pastes and oil dispersions the ingredients as such or dissolved in an oil or solvent may be homogenized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active ingredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.

Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalenesulfonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sulfated fatty alcohol glycol ether, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylphenol and ethoxylated nonylphenol, alkylphenol polyglycol ethers, tributylphenyl polyglycol ether, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignin, sulfite waste liquors and methyl cellulose.

Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid carrier.

Granules, e.g., coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid carriers. Examples of solid carriers are mineral earths such as silica gel, silicic acid, silica gels, silicates, talc, kaolin, Attaclay, limestome, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium oxide, ground plastics, fertilizers, such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain flours, bark meal, wood meal, and nutshell meal, cellulosic powders, etc.

The formulations contain from 0.1 to 95, and preferably 0.5 to 90% by weight of active ingredient.

There may be added to the compositions or individual active ingredients (if desired, immediately before use (tankmix) ) oils of various types, herbicides, fungicides nematocides, insecticides, bactericides, trace elements, fertilizers, antifoams (e.g., silicones), growth regulators, antidotes and other herbicidally effective compounds such as

substituted anilines

substituted aryloxycarboxylic acids and salts, esters and amides thereof,

substituted ethers

substituted arsonic acids and their salts, esters and amides

substituted benzimidazoles

substituted benzisothiazoles

substituted benzothiadiazinone dioxides

substituted benzoxazines

substituted benzoxazinones

substituted benzothiadiazoles

substituted biurets

substituted quinolines

substituted carbamates

substituted aliphatic carboxylic acids and their salts, esters and amides

substituted aromatic carboxylic acids and their salts, esters and amides

substituted carbamoylalkylthiol- or -dithiophosphates

substituted quinazolines

substituted cycloalkylamidocarbothiolic acids and their salts, esters and amides

substituted cycloalkylcarbonamidothiazoles

substituted dicarboxylic acids and their salts, esters and amides

substituted dihydrobenzofuranyl sulfonates

substituted disulfides

substituted dipyridylium salts

substituted dithiocarbamates

substituted dithiophosphoric acids and their salts, esters and amides

substituted ureas

substituted hexahydro-1H-carbothioates

substituted hydantoins

substituted hydrazides

substituted hydrazonium salts

substituted isoxazole pyrimidones

substituted imidazoles

substituted isothiazole pyrimidones

substituted ketones

substituted naphthoquinones

substituted aliphatic nitriles

substituted aromatic nitriles

substituted oxadiazoles

substituted oxadiazinones

substituted oxadiazolidine diones

substituted oxadiazine diones

substituted phenols and their salts and esters

substituted phosphoric acids and their salts, esters and amides

substituted phosphonium chlorides

substituted phosphonalkyl glycines

substituted phosphites

substituted phosphoric acids and their salts, esters and amides

substituted piperidines

substituted pyrazoles

substituted pyrazole alkylcarboxylic acids and their salts, esters and amides

substituted pyrazolium salts

substituted pyrazolium alkyl sulfates

substituted pyridazines

substituted pyridazones

substituted pyridine carboxylic acids and their salts, esters and amides

substituted pyridines

substituted pyridine carboxylates

substituted pyridinones

substituted pyrimidines

substituted pyrimidones

substituted pyrrolidine carboxylic acid and its salts, esters and amides

substituted pyrrolidines

substituted pyrrolidones

substituted arylsulfonic acids and their salts, esters and amides

substituted styrenes

substituted tetrahydrooxadiazine diones

substituted tetrahydroxadiazole diones

substituted tetrahydromethanoindenes

substituted tetrahydroxadiazole thiones

substituted tetrahydrothiadiazine thiones

substituted tetrahydrothiadiazole diones

substituted aromatic thiocarbonylamides

substituted thiocarboxylic acids and their salts, esters and amides

substituted thiol carbamates

substituted thioureas

substituted thiophosphoric acids and their salts, esters and amides

substituted triazines

substituted triazoles

substituted uracils, and

substituted uretidine diones.

The last-mentioned herbicidal compounds may also be applied before or after the active ingredients or compositions thereof according to the invention.

These agents may be added to the herbicides according to the invention in a ratio by weight of from 1:10 to 10:1. The same applies to oils, fungicides, nematocides, insecticides, bactericides, antidotes and growth regulators.

In the greenhouse, various plants were treated at a growth height of from 6 to 18 cm with 0.75 kg/ha of each of the following active ingredients, each being dispersed or emulsified in 500 liters of water per hectare:

I 3-phenyl-5-phenylthiopyrazole

Ii 3-phenyl-5-benzylthiopyrazole

Iii 1-acetyl-3-phenyl-5-phenylthiopyrazole and, for comparison purposes,

Iv 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate.

After 2 to 3 weeks it was ascertained that active ingredients I, II and III had a better herbicidal action than compound IV, combined with the same crop plant compatability.

The results are given below:

In the greenhouse, loamy sandy soil was filled into pots and sown with the seeds of various plants. The soil prepared in this manner was then immediately treated with 2 kg/ha of each of the following active ingredients, each being dispersed or emulsified in 500 liters of water per hectare:

I 3-phenyl-5-phenylthiopyrazole

Ii 3-phenyl-5-benzylthiopyrazole

Iii 1-acetyl-3-phenyl-5-phenylthiopyrazole and, for comparison purposes,

Iv 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate.

After 3 to 4 weeks it was ascertained that active ingredients I, II and III had a better herbicidal action than compound IV, combined with the same crop plant compatibility.

The results are given below:

90 parts by weight of compound I is mixed with 10 parts by weight of N-methyl-.alpha.-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.

20 parts by weight of compound I is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide to 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

20 parts by weight of compound I is dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide to 1 mole of isooctylphenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

20 parts of compound I is dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between 210.degree. and 280.degree. C, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

20 parts by weight of the compound of Example 3 is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene-.alpha.-sulfonic acid, 17 parts by weight of the sodium salt of a ligninsulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquid is obtained containing 0.1% by weight of the active ingredient.

3 parts by weight of compound I is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing 3% by weight of the active ingredient.

30 parts by weight of compound I is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active ingredient is obtained having good adherence.

In the greenhouse, various plants were treated at a growth height of from 5 to 16 cm with the following active ingredients

I 3-(3',5'-dimethylphenyl)-5-phenylthiopyrazole, 0.75 kg/ha + 2 l/ha of the adduct of 6 to 7 moles of ethylene oxide to 1 mole of isooctylphenol

Ii 1-[.alpha.-(2,4-dichlorophenoxy)-propionyl]-3-phenylthiopyrazole, 0.75 kg/ha + 2 l/ha of the adduct of 6 to 7 moles of ethylene oxide to 1 mole of isooctylphenyl.

Each composition was dispersed or emulsified in 500 liters of water per hectare.

After 2 to 3 weeks it was ascertained that active ingredients I and II had a good herbicidal action and good crop plant compatability.

The results are given below:

In the greenhouse, loamy sandy soil was filled into pots and sown with various seeds. The soil was then immediately treated with 2 kg/ha of each of the following active ingredients, each being dispersed or emulsified in 500 liters of water per hectare:

I 3-(,5'-dimethylphenyl)-5-phenylthiopyrazole

Ii 1-[.alpha.(2,4-dichlorophenoxy)-propionyl]-3-phenyl-5-phenylthiopyrazole.

After 4 to 5 weeks it was ascertained that active ingredients I and II had a good herbicidal action and good crop plant compatibility.

The results are given below:

The action of the following compounds corresponds to that of those in Examples 17 and 18:

3-phenyl-5-methylthiopyrazole

3-isopropyl-5-phenylthiopyrazole

3-cyclohexyl-5-phenylthiopyrazole

3-thiophenyl-5-phenylthiopyrazole

1-benzyl-3-phenyl-5-phenylthiopyrazole

1-phenyl-3-phenyl-5-phenylthiopyrazole

1-benzoyl-3-phenyl-5-phenylthiopyrazole

1-(N-methylcarbamoyl)-3-phenyl-5-phenylthiopyrazole

1-(N-phenylcarbamoyl)-3-phenyl-5-phenylthiopyrazole