GB2083807A

GB2083807A - H-Benzylpivalylamide derivatives, their production and use as herbicides

Info

Publication number: GB2083807A
Application number: GB8039051A
Authority: GB
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 1980-11-10
Filing date: 1980-12-05
Publication date: 1982-03-31
Also published as: JPS5782034A

Abstract

A compound of the formula: <IMAGE> wherein X is a methyl group, an ethyl group, a chlorine atom, a bromine atom, a fluorine atom or an iodine atom, is useful as a herbicide. The above compounds show a very broad herbicidal spectrum.

Description

SPECIFICATION N-Benzylpivalylamide derivatives, and their production and use The present invention relates to N-benzylpivalylamide derivatives, and their production and use.

The novel N-benzylpivalylamide derivaties of the invention are represented by the general formula:

wherein X is a methyl group, an ethyl group, a chlorine atom, a bromine atom, a fluorine atom or an iodine atom, preferably a methyl group, a chlorine atom or a fluorine atom.

Whilst the prevention and destruction of perennial weeks such as purple nutsedge (Cyperus rotundus) and yellow nutsedge (Cyperus Esculentus) in farmland is generally difficult, it has now been found that the N-benzylpivalylamide derivatives of formula (1) show a strong herbicidal activity against them on pre-emergence or post-emergence treatment. It has also been found that the N-benzylpivalylamide derivatives (1) exhibit a strong herbicidal activity against paddy field perennial weeks such as Cyperus serotinus, Scirpus Hotarui, slender spikerush (Eleocharis aciculalis) and Eleocharis kuroguwai, the prevention and destruction of which are quite difficult.

In addition, the N-benzylpivalylamide derivatives of formula (I) are very effective in preventing and destroying farmland annual weeds such as barnyard grass (Echinochloa crus-galli), large crabgrass (Digitaria sanguinalis), red root pigweed (Amaranthus retroflexus), common purslane (Portulaca oleracea) and common lambsquarters (Chenopodium album) and paddy field annual weeds such as Echinochloa crus-galli, pickeral weed (Monochoria vaginalis) and false pimpernel (Lindernia pyxdaria). Thus, the N-benzylpivalylamide derivatives of formula (I) show a very broad herbicidal spectrum.

The N-benzylpivalylamide derivatives of formula (I) are very effective when applied to farmland, particularly by soil surface treatment or on mixing with the soil prior to the emergence of weeds without causing any harm to the various crop plants (e.g. rice, soybean, cotton, corn, sugarbeet, wheat, peanut, sunflower) and vegetables (e.g. lettuce, cabbage) which is a distinct advantage.

Accordingly, the N-benzylpivalylamide derivatives of formula (I) are useful as herbicides when applied to paddy fields and farmland. They are also useful as herbicides for use in orchards, on lawns, pastures, gardens, mulberry fields, rubber plantations, forests and non-agricultural land.

Japanese Patent Publication No. 88228/1973 and U.S. Patent No. 3,498,781 disclose some pivalic acid amide derivatives, which are somewhat similar in chemical structure to the Nbenzylpivalylamide derivatives of formula (I) and are also herbicides. However, the herbicidal activity of the N-benzylpivalylamide derivatives of formula (I) is generally much better than that of the pivalic acid amide derivatives. It is particularly notable that, in comparison with the pivalic acid amide derivatives, the N-benzylpivalylamide derivatives of formula (I) exert an extremely large herbicidal effect without any phytoxicity to crop plants, due to its characteristic X group where X is as above defined.

The N-benzylpivalylamide derivatives of formula (I) can be produced by reacting a benzylamine derivative of the formula:

wherein X is as defined above, with pivalic acid or a reactive derivative thereof.

The benzylamine derivatives (II) may be synthesized, for instance, by the method as disclosed in J.Am.Chem.Soc., 71, 3929 (1949).

In the reaction 0.4 to 1.5 equivalents, preferably of 0.5 to 1.1 equivalents of the pivalic acid or its reactive derivative may be used to one equivalent of the benzylamine derivative of formula (II). The reaction may be carried out in the presence or absence of an inert solvent. Examples of a suitable inert solvent include hydrocarbons (e.g. benzene, toluene, xylene), halogenated hydrocarbons (e.g. chlorobenzene, methylene chloride, chloroform, carbon tetrachloride), ethers (e.g. diisopropyl ether, tetrahydrofuran, dioxane), alcohols (e.g. methanol, c-thanol, isopropanol), ketones (e.g. acetone, methylethylketone, methylisobutylketone), esters (e.g. ethyl acetate), nitriles (e.g. aceto-nitrile), dimethylsulfoxide, dimethylformamide and water. Particularly preferred among them is benzene.The reaction may be carried out within a wide temperature range from the freezing point to the boiling point of the reaction mixture, preferably from O"C to the boiling point of the reaction mixture. If necessary, cooling or heating may be used.

Depending on whether the free pivalic acid or its reactive derivative, which may include an acid anhydride, acid chloride, acid bromide or carboxylic acid ester, is used an appropriate reaction aid may be employed.

In case of the free acid, dicyclohexylcabodiimide, phosphorus pentachloride, phosphorus tetrachloride, phosphorus tribromide, thionyl chloride, sodium hydroxide, potassium hydroxide, sodium ethoxide, sodium methoxide, triethylamine, pyridine, quinoline, isoquinoline, N,Ndimethylaniline, N,N-diethylaniline or N-methylmorpholine, are suitable as reaction aids. In case of the acid chloride or acid bromide, sodium hydroxide, potassium hydroxide, sodium ethoxide, sodium methoxide, triethylamine, pyridine, quinoline, isoquinoline, N,N-dimethylaniline, N,Ndiethylaniline, N-methylmorpholine or sodium acetate, are suitable, preferably triethylamine, as the reaction aid.The amount of reaction aid used may range from a catalytic amount to 1.5 equiva:ents, preferably from 0.95 to 1.1 equivalents to one equivalent of the material to be eliminated from the starting compounds as the results of the reaction.

The recover of the reaction product from the reaction mixture may be carried out in a known manner. For example, the reaction mixture may be filtered and/or washed with water, followed by distillation for removal of the solvent to give the reaction product i.e. the N-benzylpivalyamide derivative of formula (I). If desired, this reaction product maybe purified by a known procedure such as recrystallization from an appropriate solvent such as benzene, toluene, methanol, ethanol or chloroform.

Practical embodiments of the preparation of the N-benzylpivalylamide derivatives (I) are illustrated in the following example.

Example 1 Benzene (100 ml), o-chloro-a, cY-dimethylbenzylamine (8.5 g) and triethylamine (6.1 g) were added to a 200 ml four-necked flask, and pivalyl chloride (6.0 g) was dropwise added thereto at room temperature while stirring. Stirring was continued for 3 hours. After completion of the reaction, the reaction mixture was washed with water to remove triethylamine hydrochloride.

After the benzene layer was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure. The residue was recrystallized from n-hexane to give 10.8 g of N-(o chl6rn-a, a-dimethylbenzyl-pivalylamide. M.P., 106.5-107.5 C.

Elementary analysis (C14H20NOCI): Calcd.: C, 66.26 %; H, 7.94 %; N, 5.52 %; Cl, 13.97 % Found: C, 66.26 % H, 8.12 %; N, 5.59 %; Cl, 13.98 %.

Other N-benzylpivalylamide derivatives (I) are produced in the same manner as described above, of which some specific examples are shown in Table 1.

Table I

Com- Chemical structure Melting point Elementary analysis (%) pound ( C) No. C H N Halogen 1 CH3 H3C 93 - 95 Calcd. 77.21 9.93 6.00 Found 77,00 10.07 5.89 t-C4H9CONH-C-# CH3 2 CH3 CH3 108 - 109.5 Calcd. 77.21 9.93 6.00 Found 77.29 10.02 6.07 t-C4H9CONH-C-# CH3 3 CH3 118 - 119.5 Calcd. 77.21 9.93 6.00 Found. 77.20 10.05 6.03 t-C4H9CONH-C-#-CH3 CH3 4 CH3 F 91.5 - 92.5 Calcd. 70.86 8.49 5.90 Found 70.87 8.77 5.85 t-C4H9CONH-C-# CH3 5 CH3 F 119 - 120 Calcd. 70.86 8.49 5.90 Found 70.71 8.59 6.00 t-C4H9CONH-C-# CH3 (Continued)

Com- Chemical structure Melting point Elementary analysis (%) pound ( C) No. C H N Halogen 6 CH3 113 - 114.5 Calc. 70.86 8.49 5.90 Found 70.59 8.54 5.84 t-C4H9CONH-C-#-F CH3 7 CH3 Cl 106.5 - 107.5 Calcd. 66.26 7.94 5.52 13.97 (Cl) Found 66.26 8.12 5.59 13.98 (Cl) t-C4H9CONH-C-# CH3 8 CH3 Cl 127 - 218.5 Calcd. 66.26 7.94 5.52 13.97 (Cl) Found 66.27 8.11 5.59 14.08 (Cl) t-C4H9CONH-C-# CH3 9 CH3 107 - 109 Calcd. 66.26 7.94 5.52 13.97 (Cl) Found 66.13 7.79 5.43 14.15 (Cl) t-C4H9CONH-C-#-Cl CH3 10 CH3 Br 115 - 117 Calcd. 56.39 6.76 4.70 26.79 (Br) Found 56.48 6.81 4.52 26.88 (Br) t-C4H9CONH-C-# CH3 When used practically the N-benzylpivalylamide derivatives of formula (I) may be applied as such or in any preparative form such as granules, fine granules, dusts, coarse dusts, wettable powders, emulsifiable concentrates or oily suspensions.

In the production of the preparative forms, solid or liquid inert carriers or diluents may be used. The solid carrier or diluent may be a mineral powder (e.g. kaolin, bentonite, clay, montmorillonite, talc, diatomaceous earth, mica, vermiculite, gypsum, calcium carbonate, apatite), a vegetable powder (e.g. soybean powder, flour, wood powder, tobacco powder, starch, crystalline cellulose), a high molecular weight compound (e.g. petroleum resin, polyvinyl chloride, dammar gum, ketone resin), alumina, or wax.The liquid carrier or diluent may be an alcohol (e.g. methanol), an aromatic hydrocarbon (e.g. toluene, benzene, xylene, methylnaphthalene), a halogenated hydrocarbon (e.g. chloroform, carbon tetrachloride, monchlorobenzene), or ethers (e.g. dioxane, tetrahydrofuran), a ketone (e.g. acetone, methylethylketone, cyclohexanone), an ester (e.g. ethyl acetate, butyl acetate, ethylene glycol acetate), an acid amide (e.g. dimethylformamide), a nitriles (e.g. acetonitrile), an ether alcohol (e.g. ethylene glycol ethyl ether) or water.

A surface active agent used for emulsification, dispersion or spreading may be any of the nonionic, anionic, cationic and amphoteric type of agents. Examples of surface active agents include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, oxyethylene-oxypropylene polymers, polyoxyethylene alkyl phosphates, fatty acid salts, alkyl sulfates, alkyl sulfonates, alkylaryl sulfonates, alkyl phosphates, polyoxyethylene alkyl sulfates and quaternary ammonium salts. However, the surface active agent is not of course limited to these compounds. If necessary, gelatin, casein, sodium alginate, starch, agar or polyvinyl alcohol may be used as an auxiliary agent.

The herbicidal compositions of this invention generally contain from 1 to 95% by weight, preferably from 3 to 50% by weight of the N-benzylpivalylamide derivative of formula (I).

Practical embodiments of the herbicidal composition according to the invention are illustratively shown in the following Preparative Examples wherein part(s) and % are by weight.

Preparative Example 1 Fifty parts of Compound No. 2, 2.5 parts of a dodecylbenzenesulfonate, 2.5 parts of a ligninsulfonate and 45 parts of diatomaceous earth are well mixed while being powdered to obtain a wettable powder.

Preparative Example 2 Thirty parts of Compound No.4, 10 parts of emulsifier ("Sorpol SM-100" manufactured by Toho Chemical Co. Ltd.,) and 60 parts of xylene are well mixed to obtain an emulsifiable concentrate.

Preparative Example 3 Five parts of Compound No. 7, 1 part of white carbon, 5 parts of a ligninsulfonate and 89 parts of clay are well mixed while being powdered. The mixture is then kneaded with water, granulated and dried to obtain granules.

Preparative Example 4 Three parts of Compound No. 3, 1 part of isopropyl phosphate, 66 parts of clay and 30 parts of talc are well mixed while being powdered to obtain a dust.

Preparative Example 5 Forty parts of bentonite, 5 parts of a ligninsulfonate and 55 parts of clay are well mixed while being powdered. The mixture is then well kneaded with water, granulated and dried to obtain granules containing no active ingredient. Ninety-five parts of the granules thus obtained are then impregnated with 5 parts of compound No. 1 dissolved in acetone. Subsequent removal of the acetone gives granules.

Preparative Example 6 Ninety-five parts of bentonite of 16-48 mesh is impregnated with 5 parts of Compound No.

6 dissolved in acetone. Subsequent removal of the acetone gives granules.

The N-benzylpivalylamide derivative of formula (I) may be used together with other herbicides to improve their activity as herbicides, and in some cases, to produce a synergistic effect. Other herbicides which may be used include phenoxy herbicides such as 2,4-dichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxy-acetic acid and 2-methyl-4-chlorophenoxybutyric acid (including esters and salts thereof); diphenyl ether herbicides such as 2,4-dichlorophenyl-4'-nitrophenyl ether, 2,4,6-trichlorophenyl-4'-nitrophenyl ether, 2-chloro-4-trifluoromethylphenyl-3'-ethoxy-4'- nitrophenyl ether, 2,4-dichlorophenyl-4'-nitro-3'-methoxyphenyl ether and 2,4; dichlorophenyl 3'-methoxycarbonyl-4'-nitrophenyl ether; triazine herbicides such as 2-chloro-4,6-bisethylamino 1 3, 5-triazine, 2-ch!oro-4-ethylam i no-6-isopropylamino- 1, 3, 5-triazine, 2-methylth io-4, 6-bisethy- lamino-1 , 3,5-triazine and 2-methylthio-4,6-bisisopropylamino-1,3,5-triazine; urea herbicides such as 3-(3,4-dichlorophenyl)- 1 1 -dimethylurea, 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea and 1-(2,2-dimethyl-benzyl)-3-p-tolylurea; carbamate herbicides such as isopropyl-N-(3-chlorophenyl) carbonate and methyl-N-(3,4- -dichlorophenyl) carbamate; thiolcarbamate herbicides such as S- (4-chlorobenzyl)-N, N-diethyl-thiolcarbamate and S-ethyl-N, N-hexamethylenethiolcar- bamate; acid anilide herbicides such as 3,4-dichloropropylanilide, N-methoxymethyl-2,6 diethyl-α-chloroacetanilide. 2-chloro-2',6'-diethyl-N-butoxymethylacetanilide, 2-chloro-2',6'-diethyl-N-(n-propoxyethyl) acetanilide and N-chloroacetyl-N-(2,6-diethylphenyl) glycine ethyl ester; uracil herbicides such as 5-bromo-3-sec-butyl-6-methyluracil and 3-cyclohexyl-5,6-trimethyleneuracil; pyridinium chloride herbicides such as 1,1 '-dimethyl-4,4-bispyridinium chloride; phosphorus herbicides such as N,N-bis-(phosphonomethyl) glycine, O-ethyl-O-) 2-nitro-5-methylphenyl) N-sec-butylphosphoroamidothioate, S-(2-methyl-1 -piperidyl-carbonylmethyl) O,O-di-n-propyldithi- ophosphate and S-(2-methyl-1-piperidylcarbonylmethyl) O,O-diphenyldithiophosphate; toluidine herbicides such as α,α,α-2,6-dinitro-N,N-dipropyl-p-toluidine; 5-tert-butyl-3-(2,4-di chloro-5-isopropoxyphenyl)-1 , 3,4-oxadiazolin-2-one; 3-isopropyl-1 H-2, 1 , 3-benzothiadiazin (4)3H-one-2,2-dioxide; d-(ss-naphthoxy) propionanilide; 4-(2.4-dichlorobenzoyl)-l ,3-dimethylpyrazol- 5-yl-p-toluenesulfonate and the like. However, the herbicides are not limited to these examples.

The herbicides of the invention may also be applied together with insecticides, nematocides, fungicides, plant growth regulators or fertilizers.

When the N-benzylpivalylamide derivative of formula (I) is used as a herbicide, it may be applied before or after the germination of weeds in an amount within a wide range. The amount usually ranges from about 10 grams to 1 kilogram per 10 ares, preferably from about 25 grams to 500 grams per 10 ares.

The herbicidal activity of the N-benzylpivalylamide derivatives (I) is shown in the following Test Examples wherein % is by weight.

Test Example I Seeds of large crabgrass (digitaria sanguinalis), seeds of common lambsquarters (Chenopodium album), tubers of purple nutsedge (Cyperus rotundus), seeds of corn and seeds of cotton were sowed or planted in a 10 cm flower pot and covered with soil. Separately, a required amount of each test compound was formulated into an emulsifiable concentrate and diluted with water. The diluted solution was applied to the soil by means of a hand sprayer, and the thus treated soil was mixed and kept to the depth of 2 cm from the soil surface. Cultivation was carried out in a greenhouse, and the herbicidal activity and phytotoxicity of the test compound were checked 20 days after the application. The test results are shown in Table 2. The herbicidal activity was evaluated in figures ranging from 0 to 5.The phytotoxicity to the crop plants was also indicated on the same standard as that of the herbicidal activity.

Figures Percentage of growth inhibition (%) 0 0- 9 1 10- 29 2 30- 49 3 50- 69 4 70- 89 5 90-100 Table 2 Dosage (weight Herbicidal activity Phytotoxicity of ac Com- tive in- Large Common pound gredient, crab- lambs- Purple No. g/are) grass quarters nutsedge Corn Cotton 1 20 5 5 5 0 0 10 5 5 5 0 0 2 20 5 5 5 0 0 10 5 4 4 0 0 3 20 5 4 5 0 0 10 5 4 4 0 0 4 20 5 4 5 0 0 10 5 4 5 0 0 5 20 5 4 5 0 0 10 5 4 5 0 0 6 20 5 4 5 0 0 10 5 4 5 0 0 7 20 5 5 5 0 0 10 5 4 5 0 0 8 20 5 4 5 0 0 10 5 4 5 0 0 9 20 5 4 5 0 0 10 5 4 4 0 0 10 20 5 4 5 0 0 10 5 4 4 0 0 A-') 20 0 0 0 0 0 10 0 0 0 0 0 B2) 20 2 2 1 0 1 10 1 0 0 0 1 C'3 20 2 2 1 0 1 10 0 1 0 0 0 D4) 20 1 1 0 0 0 10 0 0 0 0 0 Note: "1) Compound disclosed in Japanese Patent Publication No. 88228/1973::

*2) Compound disclosed in U.S. patent 3,498,781:

*3) Compound disclosed in U.S. patent 3,498,781:

*4) Compound disclosed in U.S. patent 3,498,781:

Test Example II A Wagner's pot 14 cm in diameter was filled with 1.5 kg. of paddy field soil and water was added to simulate conditions in a paddy field. Rice seedlings of the 3-leaf growth stage were planted in the pot, and seeds of barnyard grass (Echinochloa crus-galli) and Scirpus Hotarui, and buds of slender spikerush (Eleocharis aciculalis) were further sown or planted therein. The required amount of each test compound was applied to the soil under a flooded condition.

Twenty-five days after the application, the herbicidal activity and phytotoxicity of the test compound were checked on the plants as sown or planted and also on spontaneously germinated pickerel weed (Monochoria vaginalis). The results are shown in Table 3.

A wettable powder containing a required amount of the test compound was diluted with water and applied in a proportion of 1 5 ml/pot by means of a pipette. The herbicidal activity was evaluated according to the same criteria as in Example I.

With regard to the evaluation of phytotoxicity, the three factors (i.e. height of plant, number of tillers and total weight (dry weight)) were each checked, and a ratio of the treated plot to the untreated plot was calculated for each factor. The phytotoxicity was evaluated based on the lowest value of the three factors, which was classified into the following grades ranging from 0 to 5.

Grade Ratio of the untreated plot (%) 0 100 1 90-99 2 80-89 3 60-79 4 40-59 5 0-39 Table 3 Phyto Dosage toxi (weight Herbicidal activity city of ac Com- tive in- Barnpound gredient, yard Monochoria- Scirpus Slender Rice No. g/are) grass vaginal is Hotarui spikerush plant 1 40 5 5 5 5 0 3 40 5 5 5 5 0 4 40 4 5 5 5 0 7 40 5 5 5 5 0 8 40 4 4 5 5 0

Claims

1. A compound of the formula:

wherein X is a methyl group, an ethyl group, a chlorine atom, a bromine atom, a fluorine atom or an iodine atom.

2. A compound as claimed in claim 1, wherein Xis a methyl group, a chlorine atom or a fluorine atom.

3. A compound as claimed in claim 1, which is

4. A compound as claimed in claim 1, which is

5. A process for preparing a compound as claimed in claim 1, which comprises reacting pivalic acid or a reactive derivative thereof with a benzylamine derivative of the general formula:

wherein X is as defined in claim 1.

6. A process as claimed in claim 5 wherein the reaction is carried out in the presence of an inert solvent.

7. A process as claimed in claim 6 wherein the inert solvent is benzene.

8. A process as claimed in any one of claims 5 to 7 wherein the temperature of the reaction mixture is in the range of from 0% to the boiling point of the mixture.

9. A process as claimed in any one of claims 5 to 8 wherein a reaction aid is employed.

1 0. A process as claimed in claim 9 wherein the reaction aid is triethylamine.

11. A process as claimed in any one of claims 5 to 10 wherein the pivalic acid derivative is the acid chloride or acid bromide.

1 2. A herbicidal composition which comprises a compound as claimed in claim 1 together with an inert carrier or diluent.

1 3. A herbicidal composition as claimed in claim 1 2 wherein the content of the compound as claimed in claim 1 is in the range of from 1 to 95% by weight.

1 4. A herbicidal composition as claimed in claim 1 3 wherein the content of the compound as claimed in claim 1 is in the range of from 3 to 50% by weight.

1 5. A herbicidal composition as claimed in any one of claims 1 2 to 1 4 which also comprises one or more of a surface active agent, herbicide, insecticide, nematocide, fungicide, plant growth regulator or fertiliser.

1 6. A herbicidal composition as claimed in any one of claims 1 2 to 1 5 which is in the form of granules, a dust, a wettable powder, an emulsifiable concentrate or an oily suspension.

1 7. A herbicidal composition as claimed in claim 1 2 substantially as hereinbefore described in any one of the preparative examples 1 to 6.

1 8. A process as claimed in claim 5 substantially as hereinbefore described in Example 1.

1 9. A compound as claimed in claim 1 wherever produced by a process as claimed in any one of claims 5 to 11, or claim 18.

20. A method of controlling or preventing weeds which method comprises applying a herbicidally effective amount of a compound as claimed in any one of claims 1 to 5, or claim 19, to the weeds.

21. A method as claimed in claim 20 wherein the weeds are Cyperus rotundus or Cyperus esculentus.

22. A method as claimed in claim 20 or claim 21 which comprises applying the compound in an amount of from 10 grams to 1 kilogram per 10 ares.

23. A method as claimed in claim 22 which comprises applying the compound in an amount of from 25 grams to 500 grams per 10 ares.

24. A method of controlling weeds as claimed in claim 20 substantially as hereinbefore described with reference to Test Example I or Test Example II.