CH644356A5 - 4-PHENYLTHIOALKANESULPHONANILIDES AND MEANS CONTAINING THESE COMPOUNDS FOR REGULATING PLANT GROWTH. - Google Patents

Description

The invention relates to new 4-phenylthioalkanesulfonanides, which may also be present as salts suitable for agriculture.

60 The invention also relates to agents for regulating the plant growth of higher plants, which are characterized in that they contain at least one compound according to the invention or a salt thereof as active ingredient.

65 Furthermore, the invention relates to processes for the preparation of the compounds according to the invention and to a process for regulating the plant growth of higher plants.

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The compounds according to the invention have the following formula I:

SO)

in which R is a monohalomethyl group, A is a halogen atom, B is a hydrogen or halogen atom and n is 0 to 2.

The compounds of formula I according to the invention can also be present as agriculturally acceptable salts.

The agents according to the invention contain as active ingredient at least one compound according to the invention, which is optionally dispersed in an extender or carrier.

The compounds of the formula I can form salts, that is to say compounds of the formula given above, in which H is replaced by a cation which is suitable for agriculture. These salts are generally metal, ammonium and organic amine salts and can be prepared by treating a compound in the acid form with an appropriate base under mild conditions. The metal salts according to the invention include in particular the alkali salts (e.g. lithium, sodium and potassium salt) and alkaline earth salts (e.g. barium, calcium and magnesium salts) as well as the heavy metal salts (e.g. zinc and iron salts) and other metal salts such as aluminum salts. Suitable bases for the preparation of the metal salts according to the invention are above all the metal oxides, hydroxides, carbonates, bicarbonates and aloxides (alcoholates). Some salts can also be prepared by ion exchange (by reacting a salt according to the invention with an organic or inorganic salt in a cation exchange reaction). The organic amine salts usually include the salts of aliphatic (e.g. alkyl), aromatic and heterocyclic amines, as well as those with mixed such structures. The preferred amines used to prepare the salts according to the invention can be primary, secondary or tertiary and preferably contain no more than 20 carbon atoms. Such amines are e.g. Morpholine, methylcyclohexylamine, glucosamine, amines derived from fatty acids, etc. The amine and ammonium salts can be prepared by reacting the acidic form with an appropriate organic base or ammonium hydroxide. The salts listed above are compatible with agriculture, and the specially selected salt depends on the specific intended application and economic considerations. The alkali, alkaline earth, ammonium and amine salts are particularly suitable.

The salts according to the invention are often formed by reacting the precursors or intermediate products in aqueous solution. This solution can be evaporated to give the salt of the corresponding compound, usually to a dry powder. In some cases it may be more convenient to use a non-aqueous solvent such as alcohols, acetone, etc. The resulting solution can then be treated to remove the solvent, e.g. B. is evaporated under reduced pressure. Compounds of formula IA

wherein A, B and R are defined above are made according to the invention by (a) a compound of formula

B

Cl in which A and B have the meaning given above, heated in a suitable solvent in the presence of a base with thiophenol,

(b) the nitro group of the 4-phenylthionitrobenzene formed is reduced chemically or catalytically,

(c) the resulting substituted 4-phenylthioaniline is reacted with a corresponding sulfonyl chloride of the formula RS02C1, in which R has the meaning given above, or it is first reacted with an excess of the sulfonyl chloride and the resulting N-sulfonyl-4-phenylthioalkansulfonanilide with one The base is partially hydrolyzed and the compounds obtained are optionally converted into the corresponding salts.

Further compounds of the formula IB according to the invention

SO)

wherein A, B and R are defined above and n 'is 1 or 2, are obtained from compounds of the formula IA by oxidation of the thiophenyl group.

Preferred embodiments for producing compounds according to the invention are shown and described below:

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Procedure 1

(1)

nhs02r a b a b

Step 1 of process 1 is carried out by heating equimolar amounts of a substituted 4-chloro-nitrobenzene and thiophenol in a suitable solvent in the presence of an equimolar amount of a base. The solvent is one in which the reactants are soluble, such as a lower alkanol (e.g. ethanol or methanol), dimethyl sulfoxide or dimethylformamide. The base is an organic or inorganic base. Suitable organic bases are tertiary amines such as N, N-dimethylani-lin, triethylamine, pyridine, alkoxides or alcoholates, such as sodium ethylate and the like. Suitable inorganic bases are alkali hydroxides, such as sodium and potassium hydroxide, calcium hydroxide and the like. The product is isolated by conventional methods.

Reaction stage 2 is a reduction of the nitro group of the substituted 4-phenylthionitrobenzene which occurs as an intermediate. Known chemical or catalytic methods can be used. Raney nickel is a suitable catalyst for the reduction. The product is isolated by conventional methods.

The reaction of step 3 is a sulfonylation of the substituted 4-phenylthioaniline which occurs as an intermediate with a sulfonyl chloride in the presence of a base. If 1 to 2 equivalents of sulfonyl chloride are used, a mixture of the mono- and bi- (sulfonylated) product can be obtained which can be used in step 4. A larger proportion of the bi- (sulfonylated) product can be obtained if 2 or more equivalents of sul-

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fonyl chloride can be reacted in the presence of a strong base.

Suitable bases for the reaction in stage 3 are organic and inorganic bases, such as pyridine, triethylamine, dimethylcyclohexylamine and substituted pyridines and the like. Excess liquid bases can be used to avoid the use of a solvent. Stronger bases favor the formation of the bi- (sulfonylated) product over the mono- (sulfonylated).

Stage 4 is a partial hydrolysis of the intermediate (35-) sulfonylated compounds. This reaction leads to high yields. Basic hydrolysis using a strong basg such as potassium hydroxide in ethanol is used. Optionally, the stage 3 starting material can be converted directly to stage 4 product 40 using a mono (sulfonylation) reaction using one or more equivalents of sulfonyl chloride and one or more equivalents of a base. This reaction is favored by a weaker base than pyridine, such as 3-bromopyridine. 45 Level 5 is carried out using standard oxidation processes such as performed with the help of hydrogen peroxide in acetic acid, sodium metapeiodate and the like. The sulfoxide (n = 1) is formed when equimolar amounts of the oxidizing agent and the starting compound 50 are used, while the sulfone (n = 2) is formed when 2 moles (or a slight excess) of oxidizing agent are used per mole of starting substance will.

Procedure 2

nh2

(1)

bA- ^ o)

scn

(2)

The step 1 reaction of process 2 generally involves the formation of the substituted 4-thiocyanoaniline from the corresponding aniline by conventional procedures.

65 Step 2 reactions involve the formation of substituted 4-phenylthioaniline directly from the corresponding 4-thiocyanoaniline. This reaction involves the formation of a sodium mercaptide (sodium sulfide) from the

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Thiocyano group by reacting this group with sodium sulfide in aqueous dimethylformamide and subsequent arylation (ie by heating the aqueous dimethylformamide solution with copper I-oxide and an aryl halide, preferably iodobenzene. This product is identical to the starting substance of stage 3 according to process 1 and can be converted in the same way into the compounds according to the invention.

The herbicidal activity of the compounds according to the invention was determined by tests on greenhouse plants. Both pre-emergence and post-emergence activity were determined in a direct study against a selected group of weeds and grasses. The following weeds are examples used for these experiments.

Grasses:

Giant Foxtail (Setaria faberi)

Chicken millet (Echinochloa crus-galli)

Cinquefoil (Digitaria ischaemum)

common grasshopper (Agropyron repens)

yellow cypergrass (Cyperus esculentus)

broad-leaved plants:

bent back foxtail (Amaranthus retro-flexus)

Purslane (Portulaca oleracea)

wild mustard (Brassica kaber)

Field Bindweed (Convolvulus arvensis)

The compounds to be tested were dissolved in a small amount of acetone or other suitable solvent and then diluted with water to a concentration of 2000 ppm. The same proportions were diluted to a final concentration of 500 ppm. 80 ml of this solution were added to a 15 cm pot containing the weed seeds, corresponding to a concentration of 22.4 kg / ha. The use of 20 ml of the solution corresponds to a concentration of 5.6 kg / ha. All of the following irrigations were carried out from the ground. Two pots were used per treatment. Two to three weeks after the treatment, the values were determined and recorded as a percentage of the kill of the species in question before emergence compared to untreated control plants.

To determine post-emergence activity,

The same weed mixtures were grown for two to three weeks until the grasses reached a height of approximately 2.5 to 7.6 cm and the broad-leaved weeds reached a height of approximately 2.5 to 3.8 cm. They were approximately 10 s. or sprayed with the above-mentioned solution containing 2000 ppm until the leaf surface was thoroughly wetted.

The values were determined two to three weeks after the treatment and recorded as a percentage kill of the species in question, compared to untreated control plants.

The compounds according to the invention are herbicides with a broad spectrum of activity. The mechanism by which this herbicidal activity is brought about has not yet been fully elucidated. However, the compounds according to the invention also show various effects for modifying plant growth. A modification of plant growth as given here consists in all deviations from natural development, e.g. defoliation, stimulation, developmental inhibition, delay, dehydration, occurrence of giant or dwarf growth, control, etc. The activity for controlling plant growth is generally observed when the compounds according to the invention interact with certain processes within the plant. If these processes are essential, the plant dies if it is treated with a sufficient amount of the compound. However, the way plant growth is modified varies with the different plants.

For application to the plants, the compounds can be finely divided and suspended in any conventional aqueous medium. Spreading aids, wetting agents, tackifiers and other auxiliaries may also be added, if necessary. Dry powders can be used as such or diluted with inert substances such as diatomaceous earth as dusts.

The agents according to the invention are usually applied to the plants or the soil is covered with them if regulation before emergence is desired. The application can be carried out with the aid of conventional spraying devices, dusting devices and the like. The application rate is generally from 0.56 to 22.4 kg / ha, but can also be higher or lower depending on the circumstances.

The compounds according to the invention can advantageously be used together with other known herbicides in order to expand the spectrum of those weeds which are combated by the herbicides according to the invention or for better combating a weed which is not adequately controlled by special individual compounds according to the invention. Known herbicides include phenoxy herbicides e.g. 2,4-D, 2,4,5-, Silvex and the like, carbamate herbicides, thiocarbamate and dithiocarbamate herbicides, substituted ureas, e.g. Diuron, monuron and the like, triazines, e.g. Simazine and atrazine, chloroacetamide and chlorinated aliphatic acids, chlorinated benzoic acid and phenylacetic acid, paraquat, nitralin and the like. In addition, herbicidal compositions comprising compounds according to the invention can additionally contain nematicides, fungicides, insecticides, fertilizers, trace elements, agents for improving the soil and other plant growth regulators and the like.

The invention is explained in more detail by the following examples, in which the preparation of starting and intermediate products is also described.

Example 1 2-Nitro-5-phenylthiobenzotrifluoride A solution of 28.8 g (0.15 mol) of 2-nitro-5-chlorobenzotrifluoride, 16.6 g (0.15 mol) of thiophenol and 150 ml of ethanol was added under nitrogen heated to reflux temperature. A solution of 6 g (0.15 mol) of sodium hydroxide and 7 ml of water was slowly added to this solution at such a rate that the mixture boiled under reflux without external heating. The solution was then heated to reflux for a further two hours, filtered hot and the filtrate cooled. The resulting precipitate was filtered off and recrystallized from hexane. A yellow solid was obtained, mp. 65-67 ° C.

Analysis:

Calculated for C13H8F3N02S:

C 52.2 H 2.7 N 4.7%

Found:

C 52.2 H 2.6 N 4.7%

The following compound was prepared by the same general procedure: 2-chloro-4-phenylthionitrobenzene (solid).

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Example 2 4-phenylthio-2-trifluoromethylaniline 25.6 g (0.86 mol) of 2-nitro-5-phenylthiobenzotrifluoride were dissolved in 500 ml of ethanol over Raney nickel at a hydrogen pressure of approximately 0.31 N / mm2 (45 psi) reduced. After complete hydrogen uptake, the mixture was deactivated with elemental sulfur, filtered and the filtrate was evaporated to an oil under reduced pressure. The IR spectrum showed an absorption at 2.9 µm (strong NH band). The product crystallized on standing to a solid, mp 63-66.5 ° C.

The following compound was made by the same general procedure:

2-chloro-4-phenylthioaniline (solid).

Example 3 3-Chloro-4-phenylthioaniline A solution of 91.6 g (0.4 mol) of 2-bromo-4-thiocyanoaniline and dimethylformamide was added dropwise to a solution of 0.48 mol of sodium sulfide and water under nitrogen and the resulting one Solution heated to 50 ° C for 1 hour. Then 34.33 g (0.24 mol) of copper I-oxide and 97.9 g (0.48 mol) of iodobenzene were added and the mixture was heated at a bath temperature of 150 ° C. for 4.5 hours. The reaction was stopped by adding water, methylene chloride was added and the resulting mixture was filtered through a filter aid to remove suspended solids. The aqueous and organic layers were separated and the aqueous layer extracted 3 times with methylene chloride. The methylene chloride extracts were pooled, washed with water and dried. After removal of the drying agent and the methylene chloride, the desired product was obtained, from which a cleaned sample melted at 61 to 63 ° C.

Analysis:

Calculated for C12H10BrNS:

C 51.44 H 3.6 N 5.0%

Found:

C 51.9 H 3.6 N 5.0%

The following compounds were prepared by the same general procedure: 2-chloro-4-phenylthioaniline (solid) 2-fluoro-4-phenylthioaniline (solid) 2,3-dichloro-4-phenylthioaniline (solid) 2,5-dichloro-4 -phenylthioaniline (solid)

Example 4

N-chloromethylsulfonyl-4-phenylthio-2-trifluoromethyl

Chloromethanesulfonanilide 18.6 g (0.125 mol) of chloromethanesulfonyl chloride were added to a cold (0-5 ° C) solution of 13.5 g (0.05 mol) of 4-phenylthio-2-trifluoromethylaniline in 20 g (0.25 mol ) Pyridine added dropwise with stirring. The solution was stirred at room temperature overnight, poured into ice water and 12N hydrochloric acid with stirring to give N-chloromethylsulfonyl-4-phenylthio-2-trifluoromethylchloromethanesulfonanilide as an oil.

The following compound was made by the same general procedure:

N-methylsulfonyl-2-chloro-4-phenylthiomethanesulfonanilide (solid).

Example 5

4-Phenylthio-2-trifluoromethylchloromethanesulfonanilide A solution of N-chloromethylsulfonyl-4-phenylthio-2-trifluoromethylchloromethanesulfonanilide and 85% potassium hydroxide (0.15 mol) in 200 ml of ethanol was stirred overnight at room temperature. The solvent was filtered off under reduced pressure and the solid was taken up in hot water, filtered and acidified with dilute hydrochloric acid. The product was taken up in methylene chloride and dried. After removal of the dry solvent and the solvent, an oil was obtained which crystallized on standing. After recrystallization from methylene chloride / hexane, a beige solid mp 97-99 ° C. was obtained.

Analysis:

io calculated for C ^ Hj 1C1F3N02S2:

C 44.0 H 2.9 N 3.7%

Found:

C 44.0 H 2.9 N 3.7%

The following compound was prepared by the same general procedure: 2-chloro-4-phenylthiomethanesulfonanilide (solid).

Example 6 2-Bromo-4-thiocyanoaniline 20 To a cold (0.5 ° C) solution of 20.6 g (0.12 mol) o-bromoaniline and 29.2 g (0.36 mol) sodium thiocyanate in 300 ml A solution of 19.5 g (0.122 mol) of bromine in 75 ml of methanol which was saturated with sodium bromide was added dropwise to methanol with stirring. The solution was stirred for one hour after the bromine was added and then poured into 2 liters of water and neutralized with sodium carbonate. The resulting solid was collected, washed with water and dried, mp. 74-79 ° C.

The following compounds were prepared using the same general procedure:

2-chloro-4-thiocyanoaniline, mp. 63 to 65 ° C 2-fluoro-4-thiocyanoaniline, mp. 34 to 35 ° C 2,5-dichloro-4-thiocyanoaniline, mp. 111 to 115 ° C 2.3 -Dichlor-4-thiocyanoaniline, mp 132-137 ° C

35

Example 7

2-Bromo-4-phenylthiomethanesulfonanilide 26.9 g (0.23 mul) methanesulfonyl chloride were added to a 40 cold (0-5 ° C) solution of 52.5 g (0.187 mol) 2-bromo-4-phenylthioaniline in 163 g 3-chloropyridine added dropwise and the solution warmed to room temperature and stirred overnight. A further 7 g of methanesulfonyl chloride were added and the reaction mixture was heated to 50 ° C. for 45 hours. The reaction mixture was then mixed with dilute hydrochloric acid and extracted 3 times with methylene chloride. The methylene chloride was washed 3 times with water and dried. After removal of the drying agent and methylene chloride, the desired proso product remained in its crude form. It was extracted with hexane and the residue was chromatographed on silica gel using methylene chloride as the eluent. Evaporation of the methylene chloride gave a solid product which was recrystallized from hexane / methylene chloride, mp. 74.5 to 55 75 ° C.

Analse:

Calculated for C13H12BrN02S2:

C 43.58 H 3.38 N 3.91%

Found:

60 C 43.7 H 3.4 N 3.9%

The following compounds were prepared by the same general procedure: 2-chloro-4-phenylthiomethanesulfonanilide,

Mp 79.5 to 81 ° C 65 2-fluoro-4-phenylthiomethanesulfonanilide,

Mp 125 to 125.5 ° C

The following compounds were also prepared by the same general procedure, but each

after using chloromethanesulfonyl chloride or -ethansulfonyl chloride: 2-bromo-4-phenylthiochloromethanesulfonanilide,

Mp 71-72.5 ° C 2-chloro-4-phenylthiochloromethanesulfonanilide,

Mp 73-74 ° C 2-fluoro-4-phenylthiochloromethanesulfonanilide,

Mp 83-83.5 ° C 2,3-dichloro-4-phenylthiochloromethanesulfonanilide,

Mp 122-123.5 ° C 2,5-dichloro-4-phenylthiochloromethanesulfonanilide,

Mp 144-144.5 ° C 4-phenylthio-2-trifluoromethylethanesulfonanilide,

(Solid).

Example 8

4-Phenylsulfinyl-2-trifluoromethylchloromethanesulfonanilide To a solution of 2.6 g (0.0068 mol) of 4-phenylthio-2-trifluoromethylchloromethanesulfonanilide in 15 ml glacial acetic acid was added 0.77 g (0.0068 mol) 30% hydrogen peroxide. The solution was stirred at room temperature overnight, heated to just the reflux temperature and treated with water. The aqueous mixture was filtered and the tan solid washed with water and dried, mp 146-150 ° C.

Analysis:

Calculated for C ^ Hj

C 42.2 H 2.8 N 3.5%

Found:

C 42.3 H 3.0 N 3.6%

The following compounds were prepared by the same general procedure: 2-chloro-4-phenylsulfinylmethanesulfonanilide,

Mp 129-129.5 ° C 2-fluoro-4-phenylsulfinylmethanesulfonanilide,

Mp 121-122.5 ° C 2-bromo-4-phenylsulfinylmethanesulfonanilide,

Mp. 138-138.5 ° C 2-fluoro-4-phenylsulfinylchloromethanesulfonanilide, mp. 185-185.5 ° C -

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2-bromo-4-phenylsulfinylchloromethanesulfonanilide,

Mp 123.5-124 ° C 2-chloro-4-phenylsulfinylchloromethanesulfonanilide, mp. 142-143 ° C s 4-phenylsulfinyl-2-trifluoromethylethanesulfonanilide, (solid).

Example 9

4-phenylsulfonyl-2-trifluoromethylchloromethanesulfonanilide io 3 g (0.0272 mol) of 30% hydrogen peroxide were added to a solution of 2.6 g (0.0068 mol) of 4-phenylthio-2-trifluoromethylchloromethanesulfonanilide in 15 ml of glacial acetic acid. The solution was heated under reflux for 3 hours, water was added and the mixture was cooled. The resulting precipitate was filtered off, washed with water and dried to a white solid, mp. 93-97 ° C.

Analysis:

Calculated for C14Hi 1C1F3N04S2:

20 C 40.6 H 2.7 N 3.4%

Found:

C 40.6 H 2.8 N 3.5%

The following compounds were prepared by the same general procedure: 2-chloro-4-phenylsulfonylmethanesulfonanilide,

(Solid)

2-bromo-4-phenylsulfonylmethanesulfonanilide,

Mp 159-160 ° C 2-bromo-4-phenylsulfonylchloromethanesulfonanilide, 30 mp. 136-136.5 ° C 2-fluoro-4-phenylsulfonylmethanesulfonanilide,

Mp 127.5-128 ° C 2-chloro-4-phenylsulfonylmethanesulfonanilide,

Mp 152-156 ° C 35 2-chloro-4-phenylsulfonylchloromethanesulfonanilide, mp 142-142.5 ° C 2-fluoro-4-phenylsulfonylchloromethanesulfonanilide,

Mp 142-142.5 ° C 4-phenylsulfonyl-2-trifluoromethylethanesulfonanilide, 40 (solid).

Claims (7)

644 356 2nd 1.4-Phenylthioalkanesulfonanilides of the general formula (I) hnso2r fh in R is a monohalomethyl group, A is a halogen atom, B is a. Hydrogen or halogen atom and n 'represent 1 or 2, and of their salts suitable for agriculture, characterized in that after the process 5 according to claim 3, a compound of the formula IA is prepared and this is 4-phenylsulfinyl or 4 -Phenylsul-fonylalkanesulfonanilide oxidized and compounds obtained optionally converted into the corresponding salts. 5. Agent for regulating the plant growth of taller plants, characterized in that it contains at least one compound of the formula (I) as active ingredient in which R is a monohalomethyl group, A is a halogen atom, B is a hydrogen or halogen atom and n is 0 to 2, and the salts thereof which are suitable for agriculture. 2. Compounds according to claim 1, characterized in that R represents the group CH2C1. 3. Process for the preparation of compounds of formula (IA) HKS0 „R 15 20th hns02r s (O) (ia) (I) in which R is a monohalomethyl group, A is a halogen atom and B is a hydrogen or halogen atom, and of their salts suitable for agriculture, characterized in that (a) a compound of the formula no. A. I 2 25 wherein R is a monohalomethyl group, A is a halogen atom, B is a hydrogen or halogen atom and n is 0 to 2, or contains salts suitable for agriculture. 6. A process for regulating the plant growth of 30 higher plants, characterized in that the plants to be treated are treated with an effective amount of a compound of the formula I. hnso2r (I) 40 SO) in which A and B have the meaning given above, heated in a suitable solvent in the presence of a base with thiophenol, (b) the nitro group of the resulting 4-phenylthionothrobenzene is reduced chemically or catalytically, (c) the resulting substituted 4-phenylthioaniline is reacted with a corresponding sulfonyl chloride of the formula RS02C1, in which R has the meaning given above, or it is first reacted with an excess of the sulfonyl chloride and the resulting N-sulfonyl-4-phenylthioalkane-sulfonanilide partially hydrolyzed with a base and any compounds obtained are converted into the corresponding salts. 4. Process for the preparation of compounds of formula (IB) 45 in which R is a monohalomethyl group, A is a halogen atom, B is a hydrogen or halogen atom and n is 0 to 2, or is brought into contact with an agricultural salt thereof. 55 hns02r s (o)