GB2042526A

GB2042526A - N-alkylsulfonyl- and N- alkoxycarbonyl-substituted alkanesulfonanilides and derivatives thereof useful as plant growth modifiers

Info

Publication number: GB2042526A
Application number: GB8002854A
Authority: GB
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1979-01-29
Filing date: 1980-01-28
Publication date: 1980-09-24
Also published as: IL59240A; GB2042526B; BR8000528A; GB2117375B; JPS55129263A; FR2447372A1; IL59240A0; GB2117375A; FR2447372B1; DE3002906A1; CH644357A5

Abstract

Compounds of the formula: <IMAGE> wherein R<1> and R<2> are selected from alkyl groups containing from 1 to 4 carbon atoms and monohalomethyl, R<3> is an alkyl group containing from 1 to 4 carbon atoms or phenyl, Q is -SO2- or <IMAGE> of which the carbon atom is bonded directly to the nitrogen atom, A is halogen or CF3, B is hydrogen or halogen and n is 0-2, are useful as plant growth modifiers, and those compounds meeting at least one of the conditions: (1) at least one of R<1> and R<2> is monohalomethyl; (2) Q is <IMAGE> and (3) at least one of A and B is halogen. are novel. They may be obtained by acylating compounds of the formula: <IMAGE> and followed by oxidation when com- pounds in which n is 1 or 2 are required.

Description

SPECIFICATION N-alkylsulfonyl- andSN-alkoxycarbonyl-substituted alkanesulfonanilides and derivatives thereof This invention relates to the use of N-alkylsulfonyl and N-alkoxycarbonyl substituted alkanesulfonanilides substituted in the para position by alkylthio, alkylsulfinyl, alkylsulfonyl, arylthio, arylsulfinyl and arylsulfonyl groups and additionally substituted by halogen and/or trifluoromethyl as herbicidal agents and plant growth modifying agents. The invention also relates to compositions containing the compounds.

More particularly, the invention relate to a method for regulating the growth of higher plants which comprises contacting said plants with an effective amount of a compound of the formula

wherein R1 and R2 are selected from alkyl groups containing from 1 to 4 carbon atoms and monohalomethyl (chloromethyl, bromomethyl, iodomethyl orfluoromethyl), R3 is an alkyl group containing from 1 to 4 carbon atoms or phenyl, Q is -SO2- or

of which the carbon atom is bonded directly to the nitrogen atom of the formula, A is halogen or CF3, B is hydrogen or halogen and n is 0-2.

The invention also relates to compositions for killing or modifying the growth of higher plants comprising a compound of formula / dispersed in an agriculturally acceptable exteriding medium.

Furthermore, those compounds of formula lin which at least one of the following three conditions exists: (1) at least one of R1 and R2 is monohalomethyl; (2) Ois

and (3) at least one of A and B is halogen; are novel and form a separate aspect of the invention.

The compounds /can be prepared according to the reaction sequences outlined below: Method 1

Method2

Oxidation

Step (1 ) of Method 1 is carried out by heating a compound of the indicated structure //together with a slight excess of an alkanethiol or arylthiol in a suitable solvent in the presence of the appropriate amount of base. The solvent is one in which the reactants are soluble such as a lower alkanol (e.g. ethanol or methanol), dimethyl sulfoxide or dimethyl formamide. The base is a strong organic or inorganic base. Suitable organic bases are tertiary amines such as N,N-dimethylaniline, triethylamine, pyridine, alkoxides such as sodium ethoxide and the like. Suitable inorganic bases are alkali metal hydroxides such as sodium and potassium hydroxides, calcium hydride and the like.The product is isolated by conventional methods.

Alternatively, where R3 is an alkyl group, step (1) can be carried out by stirring a methylene chloride solution of lI and a phase transfer catalyst with an aqueous base solution of the alkanethiol. Other solvents, such as benzene and dichlorobenzene, and various catalysts, such as organic ammonium salts, can also be utilized. Ordinarily the alkanethiol in dilute aqueous base is reacted with one-half an equivalent of compound Il dissolved in methylene chloride in the presence of triethylbenzylammonium chloride (the phase transfer catalyst). However, when a branched thiol, such as 2-propanethiol or 2-methyl-2-propanethiol, is utilized, additional quantities of base and thiol are required for the best yields due to side reactions with the methylene chloride.

The reaction of step (2) is a reduction of the nitro group of the intermediate 111. Chemical or catalytic methods well known to the art are successful. Raney nickel is one suitable catalyst for the reduction. Product is isolated by conventional method.

The reaction of step (3) of Method 1 is the sulfonylation of the compound IV with a sulfonyl chloride (R1SO2Cl) in the presence of base. If one to two equivalents of the sulfonyl chloride are used, a mixture of mono- and bis-(sulfonylated) product can be obtained. If two or more equivalents of the sulfonyl chloride are reacted in the presence of a strong base, more of the bis(sulfonylated) product is obtained. Suitable bases for the reaction of step (3) are organic and inorganic bases such as pyridine, triethylamine, dimethylcyclohexylamine, substituted pyridines and the like. Liquid bases in excess can be used to eliminate the need for a solvent. Stronger bases promote the formation of bis(sulfonylated) product over mono(sulfonylated) product.

Step (4) is the mono(sulfonylation) of the intermediate /V. This reaction is sometimes favored by a base weaker than pyridine, such a 3-bromopyridine, in order to provide good yields of the desired product.

Steps (5) and (6) are the sulfonylation of the mono(sulfonylated) product Vlwith eitherthesulfonyl chloride of step (3) to give the product V, or with a different sulfonyl chloride or an acyl chloride (carboalkoxy chloride) to give the product Vll. Steps (5) and (6) may be carried out on product V/or on its salt.

Note that V and Vll both comply with formula A The reaction of step (1) of Method 2 involves the formation of a suitably substituted 4-thiocyanoaniline from the substituted aniline by means of a conventional procedure. The reaction of step (2) involves the alkylation or arylation of the thiocyano moiety. These reactions can be carried out utilizing various techniques. For example, the thiocyano moiety can be alkylated in an alcoholic sodium cyanide solution. In this reaction the alcohol determines the alkyl group. Alternatively, sodium mercaptide can be first formed from the thiocyano moiety and it can then be alkylated or arylated. Alkylation can be carried out, for example, by utilizing an alkylating agent such as an alkyl halide (methyl iodide).Arylation can be accomplished by treating an aqueous dimethyl formamide solution of the sodium mercaptide with cuprous oxide and an aryl halide, preferably iodobenzene. The resulting compounds can then be further processed by the procedure of Method 1.

The oxidation step is carried out using generally known methods such as hydrogen peroxide in acetic acid, sodium metaperiodate and the like. The sulfoxide compound (n=1 ) is produced when equimolar amounts of the oxidizing agent and the reactant are utilized, whereas the sulfone (n=2) is prepared directly utilizing 2 moles (or a slight excess) of the oxidizing agent per mole of reactant.

In addition to the specific reactions shown, compound VI can be first oxidized (to compounds in which n is either 1 or 2) then further reacted as in step (5) or step (6) of Method 1 to give the corresponding compound X.

The herbicidal activity of the compounds of the invention has been determined using screening tests against greenhouse plantings. Both pre- and post-emergence activity are determined in a direct screen against selected weed species. The following weeds are examples of weeds which are used for these tests.

Grasses: Giant foxtail {Setaria faberi) Barnyardgrass FEchinochloa crus-galli) Crabgrass rDigitaria ischaemum) Quackgrass (Agropyron repens) Yellow nutsedge (Cyperus esculentus) Broadleaves: Pigweed rAmaranthus retroflexus) Purslane {Portulaca oleracea) Wild mustard {Brassica kaber) Field bindweed {Convolvulus arvensis) The test chemicals are dissolved in a small amount of acetone or other suitable solvent and then diluted with water to give a concentration of 2000 ppm. From this concentration aliquots are diluted to give a final concentration of 500 ppm. Eighty ml. of this solution are added to a 6-inch pot containing the weed seeds to give a concentration equal to 5 Ib/acre.All subsequent waterings are made from the bottom. Two pots are used per treatment. Data are taken 2 to 3 weeks after treatment and recorded as percent pre-emergence kill for each species compared to the untreated controls.

To assess post-emergence activity, the same weed mixtures are allowed to grow from two to three weeks until the grasses are approximately 1 to 3 inches and the broadleaves 1 to 1-1/2 inches tall. They are sprayed for approximately 10 seconds or until good wetting of the leaf surfaces occurs with a 2000 ppm solution as described above.

Data are taken two to three weeks after treatment and recorded as percent kill for each species compared to the untreated controls.

The compounds of this invention are broadly active as herbicides. The mechanism(s) by which this herbicidal activity is effected is not presently known. However, the compounds of this invention also show various types of plant growth modifying activity. Plant growth modification as defined herein is any deviation from natural development, for example, defoliation, stimulation, stunting, retardation, desiccation, tillering, dwarfing, regulation and the like. This plant growth modifying activity is generally observed as the compounds of the invention begin to interfere with certain processes within the plant. If these processes are essential, the plant will die if treated with a sufficient dose of the compound. However, the type of growth modifying activity observed varies among types of plants.

For application to plants, the compounds can be finely divided and suspended in any of the usual aqueous media. In addition, spreading agents, wetting agents, sticking agents or other adjuvants can be added as desired. Dry powders, as such or diluted with inert materials such as diatomaceous earth, can likewise be used as dusts for this purpose. The preparations are coated on the plants or the ground is covered when pre-emergence control is desired. Application is made with the usual sprayers, dust guns and the like.

Application rates are at 0.5 to 20 Ibs/acre in general, but may be increased or reduced according to individual circumstances of use.

The compounds of the invention may advantageously be combined with other known herbicides to broaden or maximize the weed spectrum controlled by herbicidal compositions of this invention or to better control a weed not well controlled by specific compounds of the invention. Among these other known herbicides are phenoxy herbicides, e.g. 2,4-D, 2,4,5-T, silvex and the like, carbamate herbicides, thiocarbamate and dithiocarbamate herbicides, substituted urea herbicides, e.g. diuron, monuron and the like, triazine herbicides, e.g. simazine and atrazine, chloroacetamide and chlorinated aiiphatic acid herbicides, chlorinated benzoic and phenylacetic acid herbicides such as chloramben and other herbicides such as trifluralin, paraquat, nitralin and the like.Furthermore, herbicidal compositions containing compounds of the invention may contain, in addition, nematicides, fungicides, insecticides, fertilizers, trace metals, soil conditioners, other plant growth regulators and the like. Such combinations are clearly envisioned in this invention.

The compounds which are presently preferred for use in the process of the present invention are: TABLE N-methylsu If onyl-4-ethylthio-2-trifluoromethyl methanesulfonanilide, NmethylsulfonylAethylsulfonyl2trifluornmethylmethanesulfonanilide, N-methylsulfonyl-4-t-butylthio-2-trifluoromethylmethanesulfonanilide, N-chloromethylsulfonyl-4-ethylthio-2-trifluoromethylchloromethanesulfonanilide.

N-chloromethylsulfonyl-4-ethylsulfonyl-2-trifluoromethylchloromethanesulfonanilide, N-carboethoxy-4-methylthio-2-trifluoromethylmethanesulfonanilide, N-carboethoxy-4-methylsulfinyl-2-trifluoromethylmethanesulfonanilide, and N-carboethoxy-4-methylsulfonyl-2-trifluoromethylmethanesulfonanilide.

The following examples are given for the purpose of further illustrating the present invention but are not intended, in any way, to be limiting on the scope thereof. All parts are given by weight unless otherwise specifically noted.

The subject matters of the various examples are as follows: Examples 1-3: The preparation of compounds Ill by step (1 ) of Method 1.

Examples 4-5: The preparation of compounds /V by step (2) of Method 1.

Example 6: The preparation of compounds V/ by step (4) of Method 1.

Example 7: The preparation of compounds IXby step (1 ) of Method 2.

Examples 8-10: The preparation of compounds IV by step (2) of Method 2.

Example 11: The preparation of compounds V by step (3) of Method 1.

Examples 12-13: The preparation of compounds X by the Oxidation method.

Example 14: The preparation of compounds V by step (5) of Method 1.

Example 15: The preparation of compounds Vll by step (6) of Method 1 and carrying out an analogous reaction on compounds in an oxidated state (i.e. in which n is 1 or 2).

EXAMPLE 1 2-Nitro-5-ethylthiobenzotrifluoride Asolution of 5-chloro-2-nitrobenzotrifluoride (150 g., 0.67 mole) and benzyltriethylammonium chloride (15 g., 0.067 mole) phase transfer catalyst in methylene chloride (1500 ml.) is added to a cold (0-SC.) stirred solution of sodium hydroxide (53.2 g., 1.33 mole) and ethanethiol (97.47 g., 1.57 mole) in water (1200 ml.) over a 1.5-2 hour period. The reaction mixture is allowed to come to room temperature and is stirred for 17 hours. Thin layer chromatography on silica gel with 10 percent ether-90 percent petroleum ether (b.p. 30-60" C.) diluent indicates all of the 5-chloro-2-nitrobenzotrifluoride has reacted.The methylene chloride layer is then separated from the aqueous layer and washed with water. The methylene chloride is removed by evaporation leaving 2-nitro-5-ethylthiobenzotrifluoride as an oil.

Additional compounds also prepared using the general method of Example 1 hereof are as follows: 2-nitro-5-isopropylthiobenzotrifluoride, an oil, 2-nitro-5-tert-butylthiobenzotrifluoride, an oil.

EXAMPLE 2 2-Nitro-5-m eth ylthio b enzo trffluo ride The sodium salt of methanethiol is formed by stirring a solution of methanethiol (100 g., 2.0 moles plus a slight excess), sodium hydroxide (80 g., 2.0 moles) and ethanol (2 liters) under nitrogen at 0-5"C. for 1 hour.

To this solution is rapidly added 5-chloro-2-nitrobenzotrifluoride (451.2 g., 2.0 moles). The solution is allowed to warm to room temperature overnight and then refluxed 4 hours cooled, filtered and the solvent evaporated off under reduced pressure. The resulting oil is poured into cold water (one liter), extracted with methylene chloride, dried over magnesium sulfate and the solvent evaporated under reduced pressure to afford a yellow solid. Recrystallization from hexane affords a product having a melting point of 47-50"C.

Analysis: %C %H %N Calculated for C8H6F3NO2S: 40.5; 2.5; 5.9 Found: 40.4; 2.5; 5.6 EXAMPLE 3 2-Nitro-5-phenylthiobenzotrifluoride Asolution of 2-nitro-5-chlorobenzotrifluoride (33.8 g., 0.15 mole), benzenethiol (16.6 g., 0.15 mole) and ethanol (150 ml.) is heated to its reflux temperature under nitrogen. To this solution is slowly added a solution of sodium hydroxide (6 g., 0.15 mole) and water (7 ml.) at such a rate that refluxing continues with no external heating. The solution is then heated at its reflux temperature for an additional two hours, filtered hot, and the filtrate cooled. The resulting precipitate is collected by filtration and recrystallized from hexane to afford a yellow solid, m.p. 65-67"C.

Analysis: %C %H %N Calculated for C13H8F3NO2S: 52.2; 2.7; 4.7 Found: 52.2; 2.6; 4.7 EXAMPLE 4 4Ethylthio-2-trifluoromethylaniline A solution of 64 percent aqueous hydrazine (48.4 g., 1.5 mole) is added dropwise to a warm (50DC.) stirred solution of 2-nitro-5-ethylthiobenzotrifluoride in 95 percent ethanol (1200 ml.). After all of the hydrazine is added, the reaction mixture is heated under reflux overnight. Thin layer chromatography indicates all of the nitro compound is reduced. The reaction mixture is then filtered and concentrated under reduced pressure.

The residual golden colored liquid is taken up in methylene chloride and washed with water. The methylene chloride is removed by evaporation leaving the product, 4-ethylthio-2-trifluoromethylaniline.

Additional compounds also prepared utilizing the same general method are as follows: 4-methylthio-2-trifluoromethylaniline, an oil, 4-isopropylthio-2-trifluoromethylaniline, an oil, 4-tert-butylthio-2-trifluoromethylaniline, m.p. 68-70"C.

EXAMPLE 5 4-Phenylthio-2-trifluorom eth ylaniline 2-Nitro-5-phenylthiobenzotrifluoride (25.6 g., 0.86 mole) in ethanol (500 ml.) is reduced over Raney nickel at about 45 psi of hydrogen gas. After hydrogen uptake is complete the mixture is deactivated with elemental sulfur, filtered and the filtrate evaporated to afford product as an oil. The infrared spectrum shown an absorption at 2.9 (strong NH band).The product crystallized on standing to give a solid, m.p. 63-65"C. EXAMPLE 6 2,5Dichloro-4-eth ylthiomethanesulfonanilide Methanesulfonyl chloride (11.5 g., 0.10 mole) is added dropwise to a cold (10-20" C.) stirred solution of 2,5-dichloro-4-ethylthioaniline (21.9 g., Q.10 mole) in 3-bromopyridine (23.7 g., 0.15 mole) and the mixture is stirred overnight at room temperature. The reaction is broken up with a mortar and pestle, washed with water and filtered to recover product. Recrystallization from methylene chloride-hexane gives a gray solid, m.p.143-144"C.

The following compounds are prepared utilizing the same general method: 2-fluoro-4-methylthioethanesulfonanilide, m.p. 69-71" C., 2-fluoro-4-methylthiomethanesulfonanilid m.p. 133-1 35'C., 2-fluoro-4-methylthiochloromethanesulfonanilide, a solid, 2-bromo-4-isopropylthiomethanesulfonanilide, m.p. 82-84" C., 2-bromo-4-isopropylthioethanesulfonanilide, m.p. 62-64" C., 2-bromo-4-ethylthioethanesulfonanilide, m.p. 77.5-79.5" C., 2-chloro-4-phenylthiomethanesulfonanilide, m.p. 79.5-81' C., 2-bromo-4-phenylthiomethanesulfonanilide, m.p. 74.5-75' C., 2-fluoro-4-phenylthiomethanesulfonanilide, m.p. 125-125.5' C., 4-phenylthio-2-trifluoromethylethanesulfonanilide, a solid, 2-bromo-4-phenylthiochloromethanesulfonanilide, m.p. 71-72.5" C., 2-chloro-4-phenylthiochloromethanesulfonanilide, m.p. 73-74' C., 2-fluoro-4-phenylthiochloromethanesulfonanilide, m.p. 83-83.5" C.

EXAMPLE 7 4- Thiocyano-2-trifluorometh ylaniline To a cold (0-5" C.) stirred solution of 2-aminobenzotrifluoride (6.44 g., 0.04 mole) and sodium thiocyanate (9.72 g., 0.12 mole) in methanol (100 ml.) is added dropwise a solution of bromine (6.6 g., 0.42 mole) in methanol (25 ml.) saturated with sodium bromide. The solution is stirred for 20 minutes following the addition of bromine and then poured into water (750 ml.) and neutralized with sodium carbonate. The resulting oil is taken up in methylene chloride and dried. Removal of the drying agent and solvent gives 4-thiocyano-2-trifluoromethylaniline as an oil that solidifies on standing (8.4 g., 96 percent yield).A purified sample has a melting point of 53-55"C. and the following analysis.

Analysis: %C %H Calculated for C8H5F3N2S: 44.0; 2.3; 12.8 Found: 43.7; 2.3; 12.9 The following additional compounds are prepared using the same general method: 2-chloro-4-thiocyanoaniline, m.p. 63-65" C., 2-bromo-4-thiocyanoaniline, m.p. 74-79" C., 2-fluoro-4-thiocyanoaniline, an oil, and 2,5-dichloro-4-thiocyanoaniline, m.p. 111-11 5'C.

EXAMPLE 8 4-Methylthio-2-trifluoromethylamline A solution of 4-thiocyano-2-trifluoromethylaniline (1.09 g., 0.005 mole) and sodium cyanide (0.125 g., 0.0025 mole) in methanol (50 ml.) is refluxed for about 16 hours. Methanol is removed from the cool reaction mixture by evaporation under reduced pressure, the residue is taken up in methylene chloride, washed with water and dried. Removal of the drying agent and solvent gives the product as a yellow oil (1 g., 91 percent yield).

The following additional compounds are prepared utilizing the same general method: 4-isopropylthio-2-trifluoromethylaniline, an oil, 4-n-propylthio-2-trifluoromethylaniline, an oil, and 2-chloro-4-methylthioaniline, an oil.

EXAMPLE 9 4-Methylthio-2-trifluoromethylaniline prepared using an alternate procedure.

A solution of 4-thiocyano-2-trifluoromethylaniline (2.1 g., 0.01 mole) in ethanol (25 ml.) is added to a stirred solution of sodium sulfide nonahydrate (2.4 g., 0.01 mole) in water (5 ml.), and the mixture is warmed (50 C.) for 40 minutes. Methyl iodide (1.55 g., 0.011 mole) is added to the warm reaction all at once, and stirring is continued for 2 hours. Thin layer chromatography on silica gel with 50 percent hexane-50 percent methylene chloride diluent alongside an authentic sample shows that all of the thiocyano compound is reacted to produce the desired product.

The following additional compounds are prepared utilizing the same general method: 4-ethylthio-2-trifluoromethylaniline, an oil, 4-isopropylthio-2-trifluoromethylaniline, an oil, 4-methylthio-2-chloroaniline, an oil, 4-ethylthio-2-chloroaniline, an oil, 4-isopropylthio-2-chioroaniline, an oil, 4-ethylthio-2,5-dichloroaniline, an oil, 4-methylthio-2-fluoroaniline, an oil, 4-isopropylthio-2-bromoaniline, an oil, 4-ethylthio-2-bromoaniline, an oil, 4-ethylthio-2-fluoroaniline, an oil, 4-ethylthio-2-iodoaniline, an oil, 4-isopropylthio-2-fluoroaniline, an oil, and 4-methylthio-2-bromoaniline, an oil.

EXAMPLE 10 2-Brom o-4-ph enylthioaniline A solution of 2-bromo-4-thiocyanoaniline (91.6 g., 0.4 mole) and dimethylformamide is added dropwise to a solution of sodium sulfide (0.48 mole) and water under nitrogen, and the resulting solution is heated at 50"C for 1 hour. Cuprous oxide (34.33 g., 0.24 mole) and iodobenzene (97.9 g., 0.48 moles) are added and the mixture is heated at a heating bath temperature of 150"C. for 4.5 hours. The reaction is quenched with water, methylene chloride is added, and the resulting mixture is filtered through filter aid to remove suspended solids. The aqueous and organic layers are separated and the aqueous layer is extracted three times with methylene chloride.The methylene chloride extracts are combined, washed with water and dried. Removal of the drying agent and methylene chloride gives the desired product.

A purified sample melts at 61-63"C.

Analysis: %C %H %N Calculated for C12H10BrNS: 51.44; 3.6; 5.0 Found: 51.9; 3.6; 5.0.

The following compounds can be prepared utilizing the same general procedure: 2-chloro-4-phenylthioaniline, a solid, and 2-fluoro-4-phenylthioaniline, a solid.

EXAMPLE 11 N-Methylsulfon yI-4-ethylthio-2-trffluoromethylmethanesulfonanllide Methanesulfonyl chloride (22.2 g., 0.19 mole) is added dropwise to a cold (0-5 C.) stirred solution of 4-ethylthio-2-trif luoromethylaniline (0.077 mole) in pyridine (49 g., 0.62 mole). The solution is stirred at room temperature overnight, poured into ice water with stirring to give N-methylsulfonyl-4-ethylthio-2 trifluoromethylmethanesulfonanilide as a tan solid. Recrystallization from methylene chloride-hexane gives pure product, m.p. 137-139"C.

Analysis: %C %H %N Calculated for C11H14NO453: 35.0; 3.7; 3.7 Found: 35.1; 3.6; 3.7.

Additional compounds prepared using the same general formula are as follows: N-ethylsulfonyl-4-methylthio-2-trifluoromethylethanesulfonanilide, an oil, N-methylsulfonyl.4-n-propylthio-2-trifluoromethylmethanesulfonanilide, a solid, N-methylsulfonyl-4-tert-butylthio-3-trifluoromethylmethanesulfonanilide, m.p. 91-93'C., N-ethylsulfonyl-4-ethylthio-2-trifluoromethylethanesulfonanilide, m.p. 119-121"C., N-ethylsulfonyl-4-isopropylthio-2-trifluoromethylethanesulfonanilide, an oil, N-n-propylsulfonyl-4-methylthio-2-trifluoromethylpropanesulfonanilide, an oil, N-n-butylsulfonyl-4-methylthio-2-trifluoromethylbutanesulfonanilide, an oil, N-methylsulfonyl-4-methylthio-2-trifluoromethyimethanesulfonanEiide, m.p. 147-1 54'C., N-methylsulfonyl-4-phenylthio-2-trifluoromethyimethanesulfonanilide, m.p. 145-1 48'C., N-chlornmethylsulfonyl-4-ethylthio-2-trifluornmethylchlornmethanesulfonanilide, m.p. 89-93"C., N-ethylsulfonyl-4-tert-butylthio-2-trifluoromethylethanesulfonanilide, m.p. 99-101 'C., N-methylsulfonyl-4-ethylthio-2-chloromethanesulfonanilide, m.p. 122-125"C., and N-chloromethylsulfonyl-4-ethylthio-2-chlorochloromethanesulfonanilide, m.p. 96-97"C.

EXAMPLE 12 N-Chlorometh ylsulfon yI-4-eth ylsulfin yI-2-trffluoromethyl-chloromethanesulfonanllide To a stirred solution of N-chloromethylsulfonyl-4-ethylthio-24rifluoromethylchloromethanesulfonanilide (4.46 g., 0.01 mole) in glacial acetic acid (100 ml.) is added 30 percent hydrogen peroxide (0.01 mole). The solution is stirred overnight at room temperature. An additional amount of 30 percent hydrogen peroxide (0.001 mole) is added and stirring continued overnight, and then treated with water. The aqueous mixture is extracted with methylene chloride, washed with water and dried. Removal of the drying agent and solvent gives a solid, m.p. 166-168"C.

Analysis: %C %H %N Calculated for C11H12Cl2F3NO5S3: 28.6; 2.6; 3.0 Found: 28.9; 2.6; 3.1.

The following compounds can also be prepared utilizing the same general formula: N-methylsulfonyl-4-methylsulfinyl-2-trifluoromethyl-methanesulfonanilide, N-methylsulfonyl-2-ethylsulfinyl-2-trifluoromethylmethanesulfonanilide, and N-methylsulfonyl-4-phenylsulfinyl-2-trifluoromethylmethanesulfonanilide.

EXAMPLE 13 N-Chloromethylsulfonyl-4-ethylsulfonyl-2-trifluoromethyl-chloromethanesulfonanilide To a stirred solution of N-chloromethylsulfony-4-ethylthio-2-trifluoromethylchloromethanesulfonanilide (2.23 g., 0.005 mole) in glacial acetic acid (50 ml.) is added 30 percent hydrogen peroxide (0.02 mole). The solution is heated at reflux for 2.5 hours, water is added, and the mixture is cooled. The resulting precipitate is collected by filtration, washed with water and dried to give a white solid, m.p. 160-165"C.

Analysis: %C %H %N Calculated for CllH12C12F3NOSS3: 27.6; 2.5; 2.9 Found: 27.7; 2.4; 2.9.

An additional compound prepared using the same general method is as follows: N-methylsulfonylA-ethylsulfonyl-2-trifiuornmethylmethanesulfonanilide, m.p. 167-169"C.

The method can also be used to prepare the following compounds: N-methylsulfonyl-4-methylsulfonyl-2-trifluoromethylmethanesulfonanilide and N-methylsulfonyl-4-phenylsulfonyl-2-trifluoromethylmethanesulfonanilide.

EXAMPLE 14 N-Methylsulfonyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide Dimethylcyclohexylamine (2.57 g., 0.02 mole) is added dropwise to a cold (5-10"C.) stirred solution of 4-ethylthio-2-trifluoromethylmethanesulfonanilide (1.5 g., 0.005 mole) and methanesulfonyl chloride (0.86 g., 0.0075 mole) in benzene and the solution allowed to warm to room temperature and stirring continued for about 72 hours.Thin layer chromatography on silica gel with either methylene chloride eluant, or with a 50 percent ether-50 percent petroleum ether (b.p. 30-60'C.) eluant, or with a 25 percent ethyl acetate-75 percent petroleum ether (b.p. 30-60"C.) eluant alongside an authentic sample shows that all of the methanesulfonanilide is reacted to produce the desired N-methylsulfonylmethanesulfonanilide product.

The following additional compounds are prepared utilizing the same general method: N-methylsulfonyl-2,5-dichloro-4-ethylthiomethanesulfonanilide, m.p. 145-1 48'C., N-ethylsulfonyl-4-methylthio-24luoroethanesulfonanilide, m.p. 94-96"C., N-methylsulfonyl-4-methythio-24luornmethanesulfonanilide, m.p. 151-1 53'C., N-chloromethylsulfonyl-4-methylthio-2-fluorochloromethanesulfonanilide, m.p. 142-1 43'C., N-methylsulfonyl-4-isopropylthio-2-bromomethane sulfonanilide, m.p. 81-83" C., N-ethylsulfonyl-4-isopropylthio-2-bromoethanesulfonanilide, m.p.64-67 C., and N-ethylsulfonyl-4-ethylthio-2-bromoethanesulfonanilide, m.p. 95-97" C.

EXAMPLE 15 N-Carboethoxy-4-methylthio-2-trifluoromethylmethanesulfonanilide To a cold (0-5"C.) stirred solution of 4-methylthio-2-trifluoromethylmethanesulfonanilide (5.7 g., 0.02 mole) in pyridine (20 ml.) is added dropwise ethyl chloroformate (2.3 g., 0.024 mole). The solution is stirred overnight at room temperature and then poured into cold (0-5"C.) dilute hydrochloric acid. The solid is collected by filtration, washed with water and air dried. Recrystallization from hexane-methylene chloride gives tan crystals, m.p. 93-95"C.

Analysis: %C %H %N Calculated for C12H14F3NO4S2: 40.4; 3.9; 3.9 Found: 40.3; 4.0; 3.9.

Additional compounds prepared using the same general procedure are as follows: N-carboethoxy-4-ethylthio-2-trifluoromethylmethane su Ifonanilide, m.p. 76-78"C., N-chloromethylsulfonyl-4-ethylthio-24rifluoromethylmethanesulfonanilide, m.p. 90-93"C., N-carboethoxy-4-phenylthio-2-trifluoromethylmethanesulfonanilide, N-carboethoxy-4-phenylthio-2-fluoromethanesulfonanilide, N-carboethoxy-4-phenylthio-2-chloromethanesulfonanilide, N-carboethoxy-4-phenylthio-2-bromomethanesulfonanilide, N-carboethoxy-4-phenylthio-2-fluorochloromethanesulfonanilide, N-carboethoxy-4-phenylthio-2-chlorochloromethanesulfonanilide, N-carboethoxy-4-phenylthio-2-bromoch loromethanesu Ifonanilide, N-carboethoxy-4-phenylthio-2-trifluoromethylethanesulfonanilide.

The following compounds are prepared by reacting compounds of structure VI except that they are in a higher oxidation state (i.e. n is 1 or 2) in a manner analogous to step (6) of Method 1.

N-carboethoxy-4-methylsulfinyl-2-trifluoromethylmethanesulfonanilide, an oil, N-carboethoxy-4-methylsulfonyl-2-trifluoromethylmethanesulfonanilide, m.p. 148-150"C., N-carboethoxy-4-ethylsulfinyl-2-trifluoromethylmethanesulfonanilide, an oil, N-carboethoxy-4-ethylsulfonyl-3-trifluoromethylmethanesulfonanilide, an oil, N-carboethoxy-4-phenylsulfinyl-2-trifluoromethylmethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfonyl-2-trifluoromethylmethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfinyl-2-trifluoromethylethanesu Ifonanilide, a solid, N-carboethoxy-4-phenylsulfonyl-2-trifluoromethylethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfinyl-2-fluoromethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfinyl-2-fluorochloromethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfonyl-2-fluorochloromethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfinyl-2-chloromethanesulfonanilide, a solid, N-carboethoxy-4-phenylsu lfonyl-2-chloromethanesu Ifonanilide, a solid, N-carboethoxy-4-phenylsulfinyl-2-chlorochloromethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfonyl-2-chlorochloromethanesulfonanilide, a solid, N-carboethoxy-4-phenylsu lfinyl-2-bromomethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfonyl-2-bromomethanesulfonanilide, a solid, N-carboethoxy-4-phenylsulfinyl-2-bromochloromethanesulfonanilide, a solid, and N-carboethoxy-4-phenylsulfonyl-]-bromochloromethanesulfonanilide, a solid.

Claims

1. A method for modifying the growth of higher plants which comprises contacting said plants with an effective amount of a compound of the formula I:

wherein R' and R2 are selected from alkyl groups containing from 1 to 4 carbon atoms and monohalomethyl, R3 is an alkyl group containing from 1 to 4 carbon atoms or phenyl, Q is -SO2- or

of which the carbon atom is bonded directly to the nitrogen atom, A is halogen or CF3, B is hydrogen or halogen and n is 0-2.

2. A method according to claim 1 wherein said compound of formula I is selected from the Table herein.

3. A method according to claim 1 wherein said compound of formula I is substantially as hereinbefore described in any of Examples 11 to 15.

4. The use as a plant growth modifying agent of a compound as defined in claim 1,2 or 3.

5. A composition for modifying the growth of higher plants which comprises a compound as defined in claim 1,2 or3 dispersed in an agriculturally acceptable extending medium.

6. Acompound oftheformula

wherein R1 and R2 are selected from alkyl groups containing from 1 to 4 carbon atoms and monohalomethyl, R3 is an alkyl group containing from 1 to 4 carbon atoms or phenyl, Q is -SO2- or

of which the carbon atom is bonded directly to the nitrogen atom, A is halogen or CF3, B is hydrogen or halogen and n is 0-2, and in which at least one of the following three conditions exists: (1) at least one of R1 and R2 is monohalomethyl; (2) Qis

and (3) at least one of A and B is halogen.

7. A compound according to claim 6 selected from the Table herein.

8. A compound according to claim 6 and substantially as hereinbefore described in any of Examples 11 to 15.