GB2041371A

GB2041371A - N-substituted Alkanesulfonanilides and Derivatives Thereof Useful as Plant Growth Modifiers or Herbicides

Info

Publication number: GB2041371A
Application number: GB8002877A
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: 1980-09-10
Also published as: JPS55127357A; IL59238A; GB2041371B; IL59238A0; CH644359A5; DE3002895A1; FR2447371A1; BR8000531A; FR2447371B1

Abstract

Compounds of the formula: <IMAGE> wherein R<1> is an alkyl group containing from 1 to 4 carbon atoms or monohalomethyl, R<2> is an aliphatic group selected from alkyl groups containing up to 4 carbon atoms, allyl, propargyl, alkoxymethyl groups containing up to 5 carbon atoms and alkylthiomethyl groups containing up to 5 carbon atoms, R<3> is an alkyl group containing from 1 to 4 carbon atoms or phenyl, A is halogen or CF3, B is hydrogen or halogen and n is 0-2 are plant growth modifiers, e.g. herbicides, and may be obtained by alkylating a compound of the formula <IMAGE> optionally in the form of its alkali metal or alkaline earth metal salts, followed or precluded by oxidation when compounds in which n is 1 or 2 are required.

Description

SPECIFICATION 4-Phenylthioalkanesulfonanilides and Derivatives Thereof This invention relates to N-substituted alkanesulfonanilides substituted in the para position by alkylthio, alkylsulfinyl, alkylsulfonyl, arylthio, arylsulfinyl and arylsulfonyl groups and additionally substituted by halogen and/or trifluoromethyl. The compounds of the invention are active herbicidal agents and plant growth modifying agents. The invention also relates to herbicidal formulations containing said compounds and to the use of the compounds to regulate and control the growth of higher plants. Methods for preparing the compounds and intermediates in their preparation are also included.

More particularly, the invention relates to compounds of the formula

wherein R' is an alkyl group containing from 1 to 4 carbon atoms or monohalomethyl, R2 is an aliphatic group selected from alkyl groups containing up to 4 carbon atoms, allyl, propargyl, alkoxymethyl groups containing up to 5 carbon atoms and alkylthiomethyl groups containing up to 5 carbon atoms, R3 is an alkyl group containing from 1 to 4 carbon atoms or phenyl, A is halogen or CF3, B is hydrogen or halogen, and n is 0--2.

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

The invention also relates to the use of the compounds of formula I to modify the growth of higher plants and to kill higher plants.

The invention also relates to processes for the preparation of the compounds of formula I.

The compounds of the invention can be prepared according to the reaction sequences outlined below.

Method 1

Method 2

In Method 2 the products of steps (1) and (4) are alkali metal or alkaline earth metal salts.

Step (1) of Method 1 is carried out by heating an alkanesulfonanilide together with an alkyl halide in a suitable non-reactive solvent in the presence of the appropriate amount of base. Suitable organic bases include pyridine, triethylamine, dimethylcyclohexylamine and the like. Suitable inorganic bases are sodium and potassium carbonate and the like. The product is isolated by conventional methods.

The reaction of step (2) is the oxidation of the product of step (1). This step is carried out using conventional oxidation methods such as hydrogen peroxide in acetic acid, sodium metaperiodate and the like. The sulfoxide compound (n=1) is produced when an equimolar amount 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 the reactant.

Alternatively, the precursor of step (1) can be first oxidized as shown in step (3) of Method 1 and then further reacted by the process of step (1) to give the compounds of the invention.

The reaction of step (1) of Method 2 involves the formation of the salt of the alkanesulfonanilide.

Salt formation is carried out by conventional means. The salt product is then reacted with an alkylating agent such as an alkyl halide (methyl iodide) to produce a compound of this invention. Alternatively, oxidation may first be carried out as in (3) and this product then converted to product as in steps (1) and (2) for the unoxidized material.

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) Ba rnya rdgrass {Echinochloa crus-galliJ C ra bg ra ss tDigitaria ischaemumJ Quackgrass RAgropyron repents) Yellow nutsedge (Cyperus esculentusJ Broadleaves: Pigweed tAmaranthus retroflexusJ Purslane tPortulaca oleraceaJ Wild mustard (Brassica saber) Field bindweed {Convolvulus arvensis).

The tess 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 g;ve 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 equivaient to 20 Ib/acre. Use of 20 ml of said solution gives 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 preemergence 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 broad-leaves 1 to 1-1/2 inches tall.

They are sprayed for approximately 10 seconds or until good wetting on 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 varied 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 weil 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 aliphatic 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, and other plant growth regulators and the like. Such combinations are clearly envisioned in this invention.

The presently preferred compounds of the invention are: Table N-ethyl-2-chloro-4-isopropylthiomethanesulfonanilide, N-propargyl-4-phenylsulfinyl-2-trifluoromethylmethanesulfonanilide, N-ethyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide, N-ethyl-2-chloro-4-isopropylthioethanesulfonanilide, N-ethyl-4-phenylsulfonyl-2-trifluoromethylmethanesulfonanilide, N-methyl-4-methylthio-2-trifluoromethylmethanesulfonanilide, N-methyl-4-methylsulflnyl-2-trifluoromethylmethanesulfonanilide, N-methyl-4-methylsulfonyl-2-truornmethylmethanesulfonanilide, N-methyl-4-tert-butylthio-2-trjfluoromethylmethanesulfonanilide, and N-methyl-4-tert-butylsu If onyl-2-trifluoromethylmetha nesu If onan ilide.

The following examples of final products, intermediate compounds, and their preparation 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.

Example 1 N-ethyl-4-methylthio-2-trifluoromethyl methanesulfonanilide A mixture of 4-methylthio-2-trifluoromethylmethanesulfonanilide (14.25 g, 0.05 mole), ethyl bromide (27.25 g, 0.25 mole), sodium carbonate (26.5 g, 0.25 mole) and acetone (200 ml) is stirred at room temperature for about 72 hours and then refluxed for 3 hours. Solids are removed by filtration and the acetone by evaporation to give a dark oil. The oil is taken up in ether, the ether filtered and then washed with 10 percent sodium hydroxide, water and dried. Removal of the drying agent and ether gives an oil that solidifies on standing. The solid is slurried with petroleum ether (b.p. 30--600C) and filtered to give product, m.p. 58--600C.

Analysis: Calculated for C11H14F3N02S2: 42.2; 4.5; 4.5 Found: 42.2; 4.4; 4.5.

Additional compounds prepared using the same general method are as follows: N-methyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide, an oil, N-allyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide, an oil, N-propargyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide, m.p. 65--67 OC;; N-methyl-4-methylthio-2-trifluoromethylmethanesu Ifona nilide, m.p. 85-88 OC, N-propyl-4-methylthio-2-trifluoromethylmethanesulfonanilide, m.p. 53-550C, N-allyl-4-methylthio-2-trifluoromethylmethanesulfonanilide, m.p. 46-48 OC, N-propargyl-4-methylthio-2-trifluoromethylmethanesulfonanilide, m.p. 124-1 260C, N-methyl-4-tert-butylthio-2-trifluoromethylmethanesulfonanilide, m.p. 73--750C, N-methyl-4-phenylthio-2-trifluoromethylmethanesulfonanilide, m.p. 11 8-1 200C, N-ethyl-4-phenylthio-2-trifluoromethylmethanesulfonanalide, m.p. 109--1110C, N-methyl-2,5-dich loro-4-ethylthiomethanesulfonanilide, m.p. 1 02.5-1 040C, N-ethyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide, an oil, N-allyl-4-phenylthio-2-trifluoromethylmethanesulfonanilide, m.p. 99-101 OC, N-propargyl-4-phenylthio-2-trifluoromethylmethanesulfonanilide, m.p. 109-111 0C, N-methyl-4-ethylthio-2-trifluoromethylchloromethanesulfonanilide, m.p. 73.5-75.5 0C, N-ethyl-4-ethylthio-2-trifluoromethylchloromethanesulfonanilide, an oil, N-methyl-2-chloro-4-ethylthioch lorometh anesulfonanilide, an oil, N-ethyl-2-chloro-4-isopropylthiomethanesulfonanilide, m.p. 70-72 0C, N-ethyl-2-chloro-4-isopropylthioethanesulfonanilide, an oil, N-ethyl-2-bromo-4-ethylthiomethanesulfonanilide, an oil, N-methyi-4-tert-butylsulfonyj 2 trifluoromethylmethanesulfonanilidet m.p. 1 81-1 83 0C, N-isopropyl-2-fluoro-4-ethylthiomethanesulfonanilide, m.p. 79-81 C, N-methyl-2-bromo-4-isopropylthiomethanesulfonanilide, m.p. 91.5-93 0C, N-methyl-2-bromo-4-isopropylthioethanesulfonanilide, an oil, N-propargyl-2-fluoro-4-phenylthiochloromethanesulfonanilide, an oil, N-propargyl-2-fluoro-4-phenylsulfinylchloromethanesulfonanilide, m.p. 104-109 0C, N-propargyl-2-fluoro-4-phenylsulfonylchloromethanesulfonanilide, m.p. 92--93.5 C, N-propargyl-2-fluoro-4-phenylthiomethanesulfonanilide, m.p. 76--76.5 C, N-propargyl-2-fluoro-4-phenylsulfinylmethanesulfonanilide, an oil, N-propargyl-2-fluoro-4-phenylsulfonylmethanesulfonanilide, m.p. 142-1 43.50C, N-propargyl-2-chloro-4-phenylthiochloromethanesulfonanilide, an oil, N-propargyl-2-chloro-4-phenylsulfinylchloromethanesulfonanilide, an oil, N-methyl-2-chloro-4-phenylthiochioromethanesulfonanilide, m.p. 80.5-81.5 0C, N-methyl-2-chloro-4-phenylsulfinylchloromethanesulfonanilide, an oil, N-methyl-2-chloro-4-phenylsulfonylchloromethanesulfonanilide, an oil, N-propargyl-2-chloro-4-phenylthiometha nesu If ona nilide, a solid, N-propargyl-2-chloro-4-phenylsulfinylmethanesulfonanilide, an oil, N-propargyl-2-chloro-4-phenylsulfonylmethanesulfonanilide a solid, N-propargyl-2-bromo-4-phenylsulfinylchloromethanesulfonanilide, an oil, N-propargyl-2-bromo-4-phenylsulfonylchloromethanesulfonanilide m.p. 62.5-65.5 C, N-propargyl-2-bromo-4-phenylthiomethanesulfonanilide, m.p. 87-880C, N-propargyl-2-bromo-4-phenylsulfinylmethanesulfonanilide, an oil, N-propargyl-2-bromo-4-phenylsulfonylmethanesulfonanilide, m.p. 114.5-11 5.5 0C, N-propargyl-4-phenylthio-2-trifluoromethylethanesulfonanilide, N-propargyl-4-phenylsulfinyl-2-trifluoromethylethanesulfonanilide, N-propargyl-4-phenylsulfonyl-2-trifluoromethylethanesulfonanilide.

Example 2 N-methyl-4-methylsulfinyl-2-trif luoromethyl methanesulfonanilide To a stirred solution of N-methyl-4-methylthio-2-trifluoromethylmethanesulfonanilide (23.0 g, 0.08 mole) in glasiai acetic acid (65 ml) is added 30 percent hydrogen peroxide (9 g, 0.08 mole). The solution is stirred at room temperature for one hour and then at reflux for one hour. Water is added and the product extracted into chloroform, the chloroform extracts washed with water and dried. The drying agent is removed by filtration, hexane is added, and the chloroform-hexane mixture is filtered and cooled (ode) to obtain a solid. The solid is collected by filtration and air dried, m.p. 108--110 C.

Analysis: Calculated for C,oH,2F3N03S2: 38.1; 3.8; 4.4 Found: 38.1; 3.8; 4.5.

The following compounds are prepared using the same general method: N-ethyl-4-methylsulfinyl-2-trifluoromethylmethanesulfonanilide, m.p.100102 C, 2-fluoro-4-phenylsulfinylmethanesu lfonanilide, m.p. 1 21-1 22.50C, 2-fluoro-4-phenylsulfinylchloromethanesulfonanilide, m.p. 1 85-1 85.50C, 2-chloro-4-phenylsulfinylmethanesulfonanilide, m.p. 129-1 29.50C, 2-chloro-4-phenylsulfinylchloromethanesulfonanilide, m.p. 142-143 0C, 2-bromo-4-phenylsulfinylmethanesulfonanilide, m.p. 138--138.5 C and 2-bromo-4-phenylsulfinylchloromethanesulfonanilide, m.p. 1 23.512400.

Example 3 N-methyl-4-ethylsulfonyl-2-trif luoromethyl methanesulfonanilide To a stirred solution of N-methyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide (3.13 g, 0.01 mole) in glacial acetic acid (100 ml) is added 30 percent hydrogen peroxide (4.55 g, 0.04 mole). The solution is heated at reflux for 3.5 hours, water is added, the product is extracted into methylene chloride and the extracts are washed with water and dried. Removal of the drying agent and solvent gives the desired product as an oil.

Analysis: %C %H %N Calculated for CX,Hr4F3N04S2: 38.3; 4.0; 4.0 Found: 37.9; 4.0; 4.0.

Additional compounds prepared using the same general method are as follows: N-methyl-4-methylsulfonyl-2-trifluoromethylmethanesulfonanilide, m.p. 1 58-1 600C, N-propyl-4-methylsulfonyl-2-trifluoromethylmethanesulfonanilide, m.p.102104 C, N-ethyl-4-methylsulfonyl-2-trifluoromethylmethanesulfonanilide, m.p.100102 C, N-methyl-4-phenylsulfonyl-2-trifluoromethylmethanesulfonanilide, m.p. 131--133 C, N-ethyl-4-phenylsulfonyl-2-trifluoromethylmethanesulfonanilide, m.p. 102--1040C, N-methyl-4-ethylsulfonyl-2-trifluoromethylchloromethanesulfonanilide, m.p. 11 2-11 40C, N-methyl-4-ethylsulfonyl-2,5-dichloromethanesulfonanilide, m.p. 200-201 OC, 2-fluoro-4-phenylsulfonylmethanesulfonanilide, m.p. 127.5--128 C 127.5128 C, 2-fluoro-4-phenylsulfonylchloromethanesulfonanilide, m.p. 142-1 42.50C, 2-chloro-4-phenylsulfonylmethanesulfonanilide, m.p. 1 52-1 560C, 2-chloro-4-phenylsulfonylchloromethanesulfonanilide, m.p. 142-1 42.50C, 2-bromo-4-phenylsulfonylmethanesulfonanilide, m.p. 1 59-1 600 C, and 2-bromo-4-phenylsulfonylchloromethanesulfonanilide, m.p. 1 36-1 36.50C.

Example 4 N-propargyl-4-phenylsulfinyl-2-trifl uoro methylmethanesu If onanil ide To a stirred mixture of sodium metaperiodate (2.78 g, 0.013 mole) and aqueous methanol (56 ml, 50 percent) is added a solution of N-propargyl-4-phenylthio-2-trifluoromethylmethanesulfonanilide (5 g, 0.013 mole) in methanol (100 ml). This mixture is heated at reflux for 48 hours and additional sodium metaperiodate added, and the mixture is stirred at room temperature. The reaction mixture is poured into water, and the product is extracted into methylene chloride. The solvent is removed by evaporation and the residue chromatographed on silica gel to give the desired product, m.p. 53-580C.

Example 5 N-ethyl-4-ethylthio-2-trifl uoromethyl methanesulfonanil ide Prepared Using an Alternate Method The sodium salt of 4-ethylthio-2-trifluoromethylmethanesulfonanilide (1.5 g, 0.005 mole) prepared from a solution of sodium hydroxide in ethanol is dissolved with stirring in dimethylformamide (25 ml) and treated with ethyl iodide (1.56 g, 0.01 mole) and the solution stirred at room temperature overnight. Thin layer chromatography on silica gel alongside an authentic sample shows that the material is reacted to produce the desired product.

The following additional compounds are prepared using the same general method: N-methoxymethyl-4-ethylthio-2-trifl uoromethanesu If onanilide, a solid, N-methylthiomethyl-4-ethylthio-2-trifluoromethylmethanesulfonanilide, an oil, and N-isopropyl-2-bromo-4-ethylthiomethanesulfonanilide, an oil.

Example 6 4-thiocyano-2-trifluoromethylaniline To a cold (0--5 OC) stirred solution of 2-iaminobenzotrifluoride (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 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 to give the desired product. A purified sample has a melting point of 52-550C.

Analysis: %C %H %N 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. 63-660C, 2-bromo-4-thiocyanoaniline, m.p. 74-790C, 2,5-dichloro-4-thiocyanoaniline, m.p, 111--1150C, and 2-fluoro-4-thiocyanoaniline.

Example 7 2-chloro-4-ethylthioaniline A solution of 2-chloro-4-thiocyanoaniline (40 g, 0.22 mole) in ethanol (250 ml) is added to a stirred solution of sodium sulfide nonahydrate (58.5 g, 0.22 mole) in water (110 ml) and the mixture is warmed (500C) for 45 minutes. Ethyl iodide (36.6 g, 0.22 mole) is added and stirring is continued for 2 hours at 500C and then at room temperature overnight. The reaction is poured into water (3 liters) and the product extracted with ether. The combined extracts are washed with water and dried (CaSO4).

Removal of the drying agent and solvent gives 2-chloro-4-ethylthioaniline, an oil.

The following additional compounds are prepared utilizing the same general method: 2-bromo-4-ethylthioaniline, an oil, 2-chloro-4-isopropylthioaniline, an oil, 4-ethylthio-2-trifluoromethylaniline, an oil, 2,5-dichloro-4-ethylthioaniline, an oil, 2-fluoro-4-ethylthioaniline, an oil, and 2-bromo-4-isopropylthioaniline, an oil.

Example 8 2-chloro-4-ethylthiochloromethanesulfonanilide Chloromethanesulfonyl chloride (4 g, 0.927 mole) is added dropwise to a stirred solution of 2chloro-4-ethylthioaniline (5 g, 0.027 mole) in 3-bromopyridine (6.4 g, 0.041 mole), and the mixture is stirred overnight at room temperature. The reaction mixture is taken up in methylene chloride (200 ml) and dilute hydrochloric acid (20%, 200 ml), the layers are separated and the methylene chloride solution is washed with dilute hydrochloric acid (10%, 200 ml) three times, water and then dried (CaSO4). Removal of the drying agent and solvent gives product as a reddish oil.This oil is taken up in hexane and cooled to give the product, 2-chloro-4-ethylthiochloromethanesulfonanilide, m.p. 70- 720C.

Analysis: %C %H Calculated for CgHC12N02S2: 36.0; 3.7: 4.7 Found: 36.6; 3.fi; 4.7.

Additional compounds prepared utilizing the same general method are as follows: 2,5-dichloro-4-ethylthiomethanesulfonanilide, m.p. 1 43-1 440C, 2-chloro-4-isopropylthiomethanesulfonanilide, m.p. 7 8-800C, 2-chloro-4-isopropylthioethanesulfonanilide, m.p. 52--53 OC, 2-bromo-4-ethylthiomethanesulfonanilide, m.p. 83-85 0C, 2-fluoro-4-ethylthiomethanesulfonanilide, m.p.89--910C, 2-bromo-4-isopropylthiomethanesulfonanilide, m.p. 82--840C, 2-bromo-4-isopropylthioethanesulfonanilide, m.p. 62--640C, 2-fluoro-4-phenylthiomethanesulfonanilide, m.p. 1 25-1 25.50C, 2-fluoro-4-phenylthiochloromethanesulfonanilide, m.p. 83-83.5 0C, 2-chloro-4-phenylthiomethanesulfonanilide, m.p. 79.5-81 OC, 2-chloro-4-phenylthiochloromethanesulfonanilide, m.p. 7374C C, 2-bromo-4-phenylthiomethanesulfonanilide, m.p.74.575 C, 2-bromo-4-phenylthiochloromethanesulfonanilide, m.p. 7172.50 C, and 4-pnenylthio-2-trifluoromethylethanesulfonanilide.

Example 9 N-chloromethylsulfonyl-4-methylthio-2-trifluoromethylchloromethanesulfonanilide Chloromethanesulfonyl chloride (0.193 mole) is added dropwise to a cold (0--50C) stirred solution of 4-methyl-2-trifluoromethylaniline (16 g, 0.0774 mole) in pyridine (49 g, 0.62 mole). The solution is stirred at room temperature overnight, poured into ice water and 1 2N hydrochloric acid (50 ml) with stirring to give N-chloromethylsulfonyl-4-methylthio-2 trifluoromethylchloromethanesulfonanilide as an oil.

The following compound is prepared using the same general method: N-chloromethylsulfonyl-4-ethylthio-2-trifluoromethyl-chloromethanesulfonanilide, m.p. 89- 930C.

Example 10 4-methylthio-2-trifluoromethylchloromethanesulfonanil ide A solution of N-chloromethylsulfonyl-4-methylthio-2-trifluoromethylchloromethanesulfonanilide (23.9 g) and 85 percent potassium hydroxide (15.3 g) in methanol (180 ml) is stirred overnight at room temperature. The solvent is evaporated under reduced pressure, and the residue is taken up in hot water, filtered and then acidified with dilute hydrochloric acid. The product is filtered and dried.

Recrystallization from methylene chloride-hexane gives a golden solid, m.p. 102--104 C.

Analysis: %C %H %N %N Calculated for CgHgCIF3N 2S2: 33.8; 2.8; 4.4 Found: 33.9; 2.9; 4.4.

The following compound is prepared utilizing the same general method: 4-ethylthio-2-trifluoromethylchloromethanesulfonanilide, m.p. 107-1 090C.

Example 11 2-bromo-4-phenylthioaniline 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 500C for one hour. Cuprous oxide (34.33 g, 0.24 mole) and iodobenzene (97.7 g, 0.48 mole) are added and the mixture is heated at a heating bath temperature of 1 500C 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 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 product.

A purified sample melts at 61-630C.

Analysis: %C %H %N %N Calculated for C12H,OBrNS: 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.

Claims

1. A compound of the formula

wherein R1 is an alkyl group containing from 1 to 4 carbon atoms or monohalomethyl, R2 is an aliphatic group selected from alkyl groups containing up to 4 carbon atoms, allyl, propargyl, alkoxymethyl groups containing up to 5 carbon atoms and alkylthiomethyl groups containing up to 5 carbon atoms, R3 is an alkyl group containing from 1 to 4 carbon atoms or phenyi, A is halogen or CF3, B is hydrogen or halogen and n is 0--2.

2. A compound according to Claim 1 selected from the Table herein.

3. A compound according to Claim 1 substantially as hereinbefore described in any of Examples 1 to 5.

4. A method for modifying the growth of higher plants which comprises contacting said plants with an effective amount of a compound according to Claim 1, 2 or 3.

5. The use as a plant growth modifying agent of a compound according to Claim 1, 2 or 3.

6. A composition for modifying the growth of higher plants which comprises a compound according to Claim 1, 2 or 3 dispersed in an agriculturally acceptable extending medium.

7. A method of preparing a compound according to Claim 1, the method being substantially as hereinbefore described.

8. A method of preparing a compound according to Claim 1, the method being substantially as hereinbefore described in any of Examples 1 to 5.