CA1058217A - Selective herbicidal phenylureas - Google Patents
Selective herbicidal phenylureasInfo
- Publication number
- CA1058217A CA1058217A CA205,683A CA205683A CA1058217A CA 1058217 A CA1058217 A CA 1058217A CA 205683 A CA205683 A CA 205683A CA 1058217 A CA1058217 A CA 1058217A
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- Prior art keywords
- formula
- dimethyl
- urea
- phenylureas
- phenyl
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-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C275/00—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C275/28—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups having nitrogen atoms of urea groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C275/00—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C275/28—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups having nitrogen atoms of urea groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton
- C07C275/30—Derivatives of urea, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups having nitrogen atoms of urea groups bound to carbon atoms of six-membered aromatic rings of a carbon skeleton being further substituted by halogen atoms, or by nitro or nitroso groups
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
Abstract
Abstract of the Disclosure Herbicidal phenylureas for selectively controlling weeds in cultures of usefuls crop are disclosed. They correspond to the formula
Description
~5 ~ ~'7 The present invention relates to substituted phenyl-ureas) to processes for their preparation~ also to plant-regulating agents containing these new compounds as active substances, as well as to methods for the selective control of weeds in cultivated crops entailing the use of the new active substances or of agents containing them.
Herbicidally active phenylureas have become known from the literature in exceedingly large numbers. From the abundance of literature available to one skilled in the art, reference is made here to the following patent specifications as relevant prior art: German Patent Specification No. 935,165; US Patent Specifications Nos.
Herbicidally active phenylureas have become known from the literature in exceedingly large numbers. From the abundance of literature available to one skilled in the art, reference is made here to the following patent specifications as relevant prior art: German Patent Specification No. 935,165; US Patent Specifications Nos.
2,705,195, 2,764,478 and 2,876,088; as well as the published German Patent Application P 19 66 298.7-41.
In the US Patent Specification No. 2,876,088, reference is made, for example, to various classes of soil-sterilising substituted phenylureas known from US Patents 2,655,444 - 447 corresponding to the German Patent Specification No.
935,165. Phenylureas given as being particularly suitable total herbicidal cornpounds for the subject of this US-patent specification are those which can be alkyl- and also halogen-substituted in the phenyl radical in any position, and which carry, for example, methyl groups on the nitrogen atom not linked with the phenyl nucleus. Herbicidal phenylureas ~ 7 of this type are described also in the US Patent Specification No. 2,705,195. Furthermore, there are known from the US Patent Specification No. 2,764,478 herbicidal phenylureas which are obligatorily substituted in the 3~position of the phenyl radical by a methyl group, and additionally, in any chosen remaining positions of the phenyl radical, by halogen. A representative of this group of compounds, l,l-dimethyl-3-(3-methyl~4-chlorophenyl)-urea, is given in the mentioned US patent specification as being, in the pre-emergence application method, selective-herbicidally effective in cotton and in maize crops. On the other hand, the unsuitability of this compound for use as a selective weed-control agent in cereal crops is taught, for example, by the known German Patent Application No. P 19 66 298.7-41. Equally unsuitable for selective-herbicidal application in grain crops, as well as in a number of other useful plant crops, such as, for example, maize and soya bean crops, are the known halogenated phenylureas, l,l-dimethyl-3-(4-chloro-phenyl)-urea and 1,1-dimethyl-3-(3,4-dichlorophenyl~-urea.
The use of these two compounds in cotton crops results in the destruction or serious damaging of the crops.
On the basis of the teaching of the prior art, one skilled in the art had to accept firstly that, for the attainment of selective-herbicidal action, phenylureas methyl-substituted in the 3-position of the phenyl radical were to be
In the US Patent Specification No. 2,876,088, reference is made, for example, to various classes of soil-sterilising substituted phenylureas known from US Patents 2,655,444 - 447 corresponding to the German Patent Specification No.
935,165. Phenylureas given as being particularly suitable total herbicidal cornpounds for the subject of this US-patent specification are those which can be alkyl- and also halogen-substituted in the phenyl radical in any position, and which carry, for example, methyl groups on the nitrogen atom not linked with the phenyl nucleus. Herbicidal phenylureas ~ 7 of this type are described also in the US Patent Specification No. 2,705,195. Furthermore, there are known from the US Patent Specification No. 2,764,478 herbicidal phenylureas which are obligatorily substituted in the 3~position of the phenyl radical by a methyl group, and additionally, in any chosen remaining positions of the phenyl radical, by halogen. A representative of this group of compounds, l,l-dimethyl-3-(3-methyl~4-chlorophenyl)-urea, is given in the mentioned US patent specification as being, in the pre-emergence application method, selective-herbicidally effective in cotton and in maize crops. On the other hand, the unsuitability of this compound for use as a selective weed-control agent in cereal crops is taught, for example, by the known German Patent Application No. P 19 66 298.7-41. Equally unsuitable for selective-herbicidal application in grain crops, as well as in a number of other useful plant crops, such as, for example, maize and soya bean crops, are the known halogenated phenylureas, l,l-dimethyl-3-(4-chloro-phenyl)-urea and 1,1-dimethyl-3-(3,4-dichlorophenyl~-urea.
The use of these two compounds in cotton crops results in the destruction or serious damaging of the crops.
On the basis of the teaching of the prior art, one skilled in the art had to accept firstly that, for the attainment of selective-herbicidal action, phenylureas methyl-substituted in the 3-position of the phenyl radical were to be
- 3 -l~S~7 preferentially used, this application moreover being limited to speciflc useful plant crops, and secondly that phenylureas with higher alkyl substitution in the 3-position of the phenyl radical were not suitable as selective herbicides for practical purposes on account of a phytotoxic action too intense and too unspecific.
It has now been found that, surprisingly, the new active substances according to the present invention, which do not have the constitution alleged in the literature to be essential for selective-herbicidal action, have, contrary to the teaching of the US Patent Specification No. 29876,088, excellent selective-herbicidal properties in a number of useful-plant crops, and are also vastly superior in effectiveness against weeds and in crop compatibility to the constitutionally homologous phenyl~
ureas disclosed in the US Patent Specification No.
2,764,478.
The new phenylureas according to the invention correspond to for~ula I
~ \\ CH3 R~ H C0 - N j (I3 / : C~13 wherein ~51~7 R1 represents hydrogen or chloxine, and R2 represents ethyl, or tert.butyl.
A particularly pronounced selectivity between weeds and useful-plant crops is exhibited, even with small applied amounts, by the following compounds according to the invention which correspond to formula I wherein Rl represents hydrogen:
1,1-dimethyl-3-(3'-ethyl-phenyl)-urea, 1,1-dimethyl-3-(3'-tert.butyl-phenyl)-urea, as well as the compound according to the invention l,l-dimethyl-3-(3-ethyl-4-chlorophenyl)-urea.
The new phenylureas of formula I are prepared accord-ing to known methods, with, in principle, all processes usually employed for the preparation of urea derivatives, including processes commonly used for manufacture on a commercial scale, being applicable. A very advantageous process comprises, reacting an isocyanate of formula II
f~
1 ~ ~ N = C = O
~ (II), wherein R1 and R2 have the meanings given under formula I, with dimethylamine in a solvent or diluent inert to the D
~ - 5 reactants, for example, benzene, toluene, dioxane and other similar ones. The reaction is performed preferably in a temperature range of between room temperature and about 80C. After completion of the reaction, the phenylureas according to the invention precipitate, on cooling, from the reaction mix~ure, or are caused to precipitate by the addition of ice water to the reaction mixture. After filtration of the precipitate thus obtained, the phenyl-ureas are crystallised from suitable solvents or solvent mixtures, such as, for example, benzene/hexane.
The isocyanates used in this reaction as starting material, or the amines used for the preparation thereof, are known compounds, or are prepared by methods analogous to those known from prior art for the preparation of such compounds.
Another process for preparation of the new phenylureas of formula I consists in the reaction of compo-mds of formula III
NH - C0 - N ~ 3 ~2 ~ CH3 (III), wherein R2 has the meaning given under formula I, wi~h chlorine or with a ~hlorine-releasing agent.
The urea derivatives serving as starting materials ~5~
are advantageously chlorinated or brominated in the presence of a solvent or diluent in which they are dissolved or suspended, as well as, optionally, in the presence of an acid-binding agentj e.g. sodium acetate.
Suitable solvents or dispersing agents for the starting materials of formula III to be chlorinated or brominated are, for example, glacial acetic acid, halogenated hydrocarbons such as carbon tetrachloride, chlorobenzene, etc..
Chlorine-releasing agents used for chlorination of the compounds of formula III are, in particular, sulphuryl chloride, or organic chlorine-releasing compounds.
Chlorination of the compounds of formula III is advantageously performed in the presence of halogen-carriers, such as, for example, iron, antimony or salts thereof, or sulphur.
As for the rest, the techniques applied are those commonly used for the nucleus-halogenation of aromatic compounds.
The preferred temperature range suitable for the above-described chlorination is one between 0 and 100C; the reaction time is between half an hour and 100 hours. The processing of the reaction mixture is performed analogously to that for the previously described first preparation process.
The starting materials of formula III correspond to the final products of formula I for the case where Rl is hydrogen, and are obtained by a process corresponding to the above-described first preparation process for the phenylureas of formula I. _ 7 _ S~ .t~
The following examples illustrate the processes according to the invention, including the preparation of starting materials. Further active substances of formula I, which are prepared by one of the described processes, are shown in the following table. The temperatures are given in degrees Centigrade.
Example 1 a) 3-Isopropyl-phenylisocyanate 167 g of 3-isopropyl-aniline is reacted with phosgene by the method described in HOUBEN-WEYL, Methoden der organischen Chemie,Vol. VIII, page 122 (1952). There is obtained in practically quantitative yield 3-isopropyl phenylisocyanate, B.P. 90/11 mm Hg.
b) 1,1-dimethyl-3-(3-isopropyl-phenyl~-urea ; 64,5 g of 3-isopropyl~phenylisocyanate is added dropwise - 15 to a solution of 55 ml of 40% aqueous dimethylamine and 200 ml of dioxane. Ice water is addedg and the precipitate is collected and dried to thus obtain 72 g of 1,1-dimethyl-3-(3-isopropyl-phenyl)-urea, M.P. 102-103 (from benzene/hexane).
~ 7 Example 2 1,1-Dimethyl-3-(3-ethyl-4-chlorophenyl)-urea 37 g of 1,1-dimethyl-3-(3-ethyl-phenyl)-urea is dissolved in 250 ml of glacial acetic acid, and 18.5 ml of sulphuryl chloride is added at 15 within one hour. Stirring is maintained overnight at room temperature, and 1 litre of ice water is then added to the reaction mixture. The resulting precipitate is separated, and crystallised from ~enzene/hexane: yield 22 g of 1,1-dimethyl-3-(3-ethyl-4-chlorophenyl)-urea; M.P. 138-140.
_ g _ ., ,, . , . , . , . . ... . , . , . , .. , .. , , .. ,, . . . , . , .. , .... ,,,, .. , .,, . , . , ., .. , . , ., , . ,, . , . , .. , ",,, ., ., ", , .. . . .. . ~ .. ,, ., .,, . ~ . , .
Teb 1 e Constitution Melting poi-nt :
C l~ Nil- CO~N ~ c~l 102 - 103 C31-17 (iso) - Cl~ ,C1-13 163 - 16~
C41-lg(tert ) ..
~ CoN~C}l3 123 - 124 C ~/ C113 ~N ~ . 8l~
C~13 C4~!9 ~tel .. ) .
.
: ' .
~ '7 The compounds according to the invention possess very good herbicidal properties against Gramineae such as millet-like plants of the genera Setaria, Digitaria, Echinochloa, etc., against grasses such as Lolium species, Alopecurus, Avena fatua, etc., and also against many dicotyledonous weeds such as Amaranthus, Sesbania, Chrysanthemum, Sinapis, Ipomoea, Pastinaca, etc., without the useful crops on which the active substance is applied being damaged, even where large amounts are employed.
Useful crops that may be mentioned are, in particular, cotton and also maize, soya bean, lucerne, sorghum, and cereals such as wheat, barley and rye.
The active substances are applied either before or after emergence of the cultivated plants and of the weeds and wild grasses. The applied amounts per hectare are between 0.2 and 16.0 kg of active substance, preferably between 0.5 and 4.0 kg.
Example 3 Herbicidal action with application of the active substances before emergence (pre-emergence) of the plantsO
__ Immediately after the sowing of the test plants, the active substances are applied, as an aqueous suspension obtained from 25% wettable powders, to the surface of the soil. The seed trays are then kept in a greenhouse at 22-23C with 50-70% relative humidity.
~ 7 Each active substance is applied in amounts equivalent to 4 kg, 2 kg, l kg and 0.5 kg of actlve substance per hectare.
The test results are evaluated after 5, 15 and 25 S days; evaluation is on the basis of a scale of values from l to ~:
l = plants dead, 2 - 4 = in~ermediate stages of destruction (over 50%
irreversible damage), 5 - 8 = intermediate stages of destruction (under 50%
reversible damage), 9 = plants undamaged (control).
In this test, 19 l-dimethyl-3-(3-ethyl-4-chlorophenyl)-urea, l,l-dimethyl-3-(3-ethyl-phenyl)-urea and l,l-dimethyl-3-(3-isopropyl-phenyl)-urea prove to be very effective against grasses/millet and dicotyledonous weeds, with very good compatibility in cotton, maize, sorghum, soya bean, wheat and barley.
Example 4 Herbicidal action with application of the active substances after emergence (post-emergence) of the plants.
, _ _ The test plants are treated in the 2-4-leaf stage with aqueous suspensions of active substances obtained from ~5% wettable powders. The amounts applied correspond ..... . . . . . .. ... .. . . . .. . .
~5~
to 4 kg, 2 kg, 1 kg and 0.5 kg of active substance per hectare.
After the treatment, the plants are kept in a green-house at 22-25C with 50-70% relative humidity.
S The test results are evaluated after 14 days and 21 days. Evaluation is on the basis of a scale of values rom 1 to 9:
1 = plants dead, 2 - 4 = intermediate stages of destruction (over 50%
irreversible damage), 5 - 8 = intermediate stages of destruction (below 50%
reversible damage), 9 = plants undamaged (control).
The compounds according to the invention have a good uniform action against undesirable grasses, and, furthermore, are effective against broad-leaved weeds, and have very good compatibility with useful crops. The compo~mds specially mentioned in Example 3 prove also in this test to be particularly effec~ive against weeds and compatible with cultivated crops.
The compounds of formula I according to the invention are used in varying ways for the selective control of weeds in useful-plant crops. Thus, they may be formulated together with suitable carriers and/or distributing agents to give agents which can be applied as dusts, wettable powders, ~ 7 emulsions, granu]ates, etc., for the regulating of plant growth. The processing of the active substances to obtain the most favourable preparation for application is covered by prior art, i.e. it is part of the S general knowledge of the experts concerned. The preparation of some such agents is further described below: the given examples are intended to illustrate but in no way to limit the invention. Parts are expressed as parts by weight.
A) Dusts Equal parts of active substance according to formula I
and precipitated silicic acid are finely ground. The mixture is combined with kaolin and ~alcum to obtain dusts having preferably an active-substance content of 1 to 6%.
B) Wettable ~owders The following constituents, for example, are mixed together and finely ground to obtain a wettable powder:
50 parts of active substance according to formula I, ~ 20 par~s of Hisil1(highly adsorptive silicic acid)~
-~ 20 25 parts of bolus alba (kaolin), 3.5 parts of reaction product from p-tert.-octyl-phenol and ethylene oxide, 1.5 parts of sodium salt of 1-benzyl-2-stearyl-benzimidazole-6,3'-disulphonic acid.
~ a~ n~rk ~s~
C) Emulsion concentrate The active substance can also be formulated as an emulsion concentrate in the following manner:
20 parts of active substance according to formula I, 70 parts of xylene, and parts of a mixture of a reaction product of an alkylphenol with ethylene oxide and calcium-dodecylbenzenesulphonate are mixed together. On dilution with water to the desired concentration, there is obtained a sprayable emulsion.
Other biocidal active substances or agents can be added to the described agents according to the invention.
Thus, the new agents may contain, in addition to the mentioned compounds of formula I, e.g. insecticides, fungicides, bactericides, fungistatics, bacteriostatics, nematocides or further herbicides for the broadening of the range of action, and also, if desired, fertilisers, trace elements, etc..
It has now been found that, surprisingly, the new active substances according to the present invention, which do not have the constitution alleged in the literature to be essential for selective-herbicidal action, have, contrary to the teaching of the US Patent Specification No. 29876,088, excellent selective-herbicidal properties in a number of useful-plant crops, and are also vastly superior in effectiveness against weeds and in crop compatibility to the constitutionally homologous phenyl~
ureas disclosed in the US Patent Specification No.
2,764,478.
The new phenylureas according to the invention correspond to for~ula I
~ \\ CH3 R~ H C0 - N j (I3 / : C~13 wherein ~51~7 R1 represents hydrogen or chloxine, and R2 represents ethyl, or tert.butyl.
A particularly pronounced selectivity between weeds and useful-plant crops is exhibited, even with small applied amounts, by the following compounds according to the invention which correspond to formula I wherein Rl represents hydrogen:
1,1-dimethyl-3-(3'-ethyl-phenyl)-urea, 1,1-dimethyl-3-(3'-tert.butyl-phenyl)-urea, as well as the compound according to the invention l,l-dimethyl-3-(3-ethyl-4-chlorophenyl)-urea.
The new phenylureas of formula I are prepared accord-ing to known methods, with, in principle, all processes usually employed for the preparation of urea derivatives, including processes commonly used for manufacture on a commercial scale, being applicable. A very advantageous process comprises, reacting an isocyanate of formula II
f~
1 ~ ~ N = C = O
~ (II), wherein R1 and R2 have the meanings given under formula I, with dimethylamine in a solvent or diluent inert to the D
~ - 5 reactants, for example, benzene, toluene, dioxane and other similar ones. The reaction is performed preferably in a temperature range of between room temperature and about 80C. After completion of the reaction, the phenylureas according to the invention precipitate, on cooling, from the reaction mix~ure, or are caused to precipitate by the addition of ice water to the reaction mixture. After filtration of the precipitate thus obtained, the phenyl-ureas are crystallised from suitable solvents or solvent mixtures, such as, for example, benzene/hexane.
The isocyanates used in this reaction as starting material, or the amines used for the preparation thereof, are known compounds, or are prepared by methods analogous to those known from prior art for the preparation of such compounds.
Another process for preparation of the new phenylureas of formula I consists in the reaction of compo-mds of formula III
NH - C0 - N ~ 3 ~2 ~ CH3 (III), wherein R2 has the meaning given under formula I, wi~h chlorine or with a ~hlorine-releasing agent.
The urea derivatives serving as starting materials ~5~
are advantageously chlorinated or brominated in the presence of a solvent or diluent in which they are dissolved or suspended, as well as, optionally, in the presence of an acid-binding agentj e.g. sodium acetate.
Suitable solvents or dispersing agents for the starting materials of formula III to be chlorinated or brominated are, for example, glacial acetic acid, halogenated hydrocarbons such as carbon tetrachloride, chlorobenzene, etc..
Chlorine-releasing agents used for chlorination of the compounds of formula III are, in particular, sulphuryl chloride, or organic chlorine-releasing compounds.
Chlorination of the compounds of formula III is advantageously performed in the presence of halogen-carriers, such as, for example, iron, antimony or salts thereof, or sulphur.
As for the rest, the techniques applied are those commonly used for the nucleus-halogenation of aromatic compounds.
The preferred temperature range suitable for the above-described chlorination is one between 0 and 100C; the reaction time is between half an hour and 100 hours. The processing of the reaction mixture is performed analogously to that for the previously described first preparation process.
The starting materials of formula III correspond to the final products of formula I for the case where Rl is hydrogen, and are obtained by a process corresponding to the above-described first preparation process for the phenylureas of formula I. _ 7 _ S~ .t~
The following examples illustrate the processes according to the invention, including the preparation of starting materials. Further active substances of formula I, which are prepared by one of the described processes, are shown in the following table. The temperatures are given in degrees Centigrade.
Example 1 a) 3-Isopropyl-phenylisocyanate 167 g of 3-isopropyl-aniline is reacted with phosgene by the method described in HOUBEN-WEYL, Methoden der organischen Chemie,Vol. VIII, page 122 (1952). There is obtained in practically quantitative yield 3-isopropyl phenylisocyanate, B.P. 90/11 mm Hg.
b) 1,1-dimethyl-3-(3-isopropyl-phenyl~-urea ; 64,5 g of 3-isopropyl~phenylisocyanate is added dropwise - 15 to a solution of 55 ml of 40% aqueous dimethylamine and 200 ml of dioxane. Ice water is addedg and the precipitate is collected and dried to thus obtain 72 g of 1,1-dimethyl-3-(3-isopropyl-phenyl)-urea, M.P. 102-103 (from benzene/hexane).
~ 7 Example 2 1,1-Dimethyl-3-(3-ethyl-4-chlorophenyl)-urea 37 g of 1,1-dimethyl-3-(3-ethyl-phenyl)-urea is dissolved in 250 ml of glacial acetic acid, and 18.5 ml of sulphuryl chloride is added at 15 within one hour. Stirring is maintained overnight at room temperature, and 1 litre of ice water is then added to the reaction mixture. The resulting precipitate is separated, and crystallised from ~enzene/hexane: yield 22 g of 1,1-dimethyl-3-(3-ethyl-4-chlorophenyl)-urea; M.P. 138-140.
_ g _ ., ,, . , . , . , . . ... . , . , . , .. , .. , , .. ,, . . . , . , .. , .... ,,,, .. , .,, . , . , ., .. , . , ., , . ,, . , . , .. , ",,, ., ., ", , .. . . .. . ~ .. ,, ., .,, . ~ . , .
Teb 1 e Constitution Melting poi-nt :
C l~ Nil- CO~N ~ c~l 102 - 103 C31-17 (iso) - Cl~ ,C1-13 163 - 16~
C41-lg(tert ) ..
~ CoN~C}l3 123 - 124 C ~/ C113 ~N ~ . 8l~
C~13 C4~!9 ~tel .. ) .
.
: ' .
~ '7 The compounds according to the invention possess very good herbicidal properties against Gramineae such as millet-like plants of the genera Setaria, Digitaria, Echinochloa, etc., against grasses such as Lolium species, Alopecurus, Avena fatua, etc., and also against many dicotyledonous weeds such as Amaranthus, Sesbania, Chrysanthemum, Sinapis, Ipomoea, Pastinaca, etc., without the useful crops on which the active substance is applied being damaged, even where large amounts are employed.
Useful crops that may be mentioned are, in particular, cotton and also maize, soya bean, lucerne, sorghum, and cereals such as wheat, barley and rye.
The active substances are applied either before or after emergence of the cultivated plants and of the weeds and wild grasses. The applied amounts per hectare are between 0.2 and 16.0 kg of active substance, preferably between 0.5 and 4.0 kg.
Example 3 Herbicidal action with application of the active substances before emergence (pre-emergence) of the plantsO
__ Immediately after the sowing of the test plants, the active substances are applied, as an aqueous suspension obtained from 25% wettable powders, to the surface of the soil. The seed trays are then kept in a greenhouse at 22-23C with 50-70% relative humidity.
~ 7 Each active substance is applied in amounts equivalent to 4 kg, 2 kg, l kg and 0.5 kg of actlve substance per hectare.
The test results are evaluated after 5, 15 and 25 S days; evaluation is on the basis of a scale of values from l to ~:
l = plants dead, 2 - 4 = in~ermediate stages of destruction (over 50%
irreversible damage), 5 - 8 = intermediate stages of destruction (under 50%
reversible damage), 9 = plants undamaged (control).
In this test, 19 l-dimethyl-3-(3-ethyl-4-chlorophenyl)-urea, l,l-dimethyl-3-(3-ethyl-phenyl)-urea and l,l-dimethyl-3-(3-isopropyl-phenyl)-urea prove to be very effective against grasses/millet and dicotyledonous weeds, with very good compatibility in cotton, maize, sorghum, soya bean, wheat and barley.
Example 4 Herbicidal action with application of the active substances after emergence (post-emergence) of the plants.
, _ _ The test plants are treated in the 2-4-leaf stage with aqueous suspensions of active substances obtained from ~5% wettable powders. The amounts applied correspond ..... . . . . . .. ... .. . . . .. . .
~5~
to 4 kg, 2 kg, 1 kg and 0.5 kg of active substance per hectare.
After the treatment, the plants are kept in a green-house at 22-25C with 50-70% relative humidity.
S The test results are evaluated after 14 days and 21 days. Evaluation is on the basis of a scale of values rom 1 to 9:
1 = plants dead, 2 - 4 = intermediate stages of destruction (over 50%
irreversible damage), 5 - 8 = intermediate stages of destruction (below 50%
reversible damage), 9 = plants undamaged (control).
The compounds according to the invention have a good uniform action against undesirable grasses, and, furthermore, are effective against broad-leaved weeds, and have very good compatibility with useful crops. The compo~mds specially mentioned in Example 3 prove also in this test to be particularly effec~ive against weeds and compatible with cultivated crops.
The compounds of formula I according to the invention are used in varying ways for the selective control of weeds in useful-plant crops. Thus, they may be formulated together with suitable carriers and/or distributing agents to give agents which can be applied as dusts, wettable powders, ~ 7 emulsions, granu]ates, etc., for the regulating of plant growth. The processing of the active substances to obtain the most favourable preparation for application is covered by prior art, i.e. it is part of the S general knowledge of the experts concerned. The preparation of some such agents is further described below: the given examples are intended to illustrate but in no way to limit the invention. Parts are expressed as parts by weight.
A) Dusts Equal parts of active substance according to formula I
and precipitated silicic acid are finely ground. The mixture is combined with kaolin and ~alcum to obtain dusts having preferably an active-substance content of 1 to 6%.
B) Wettable ~owders The following constituents, for example, are mixed together and finely ground to obtain a wettable powder:
50 parts of active substance according to formula I, ~ 20 par~s of Hisil1(highly adsorptive silicic acid)~
-~ 20 25 parts of bolus alba (kaolin), 3.5 parts of reaction product from p-tert.-octyl-phenol and ethylene oxide, 1.5 parts of sodium salt of 1-benzyl-2-stearyl-benzimidazole-6,3'-disulphonic acid.
~ a~ n~rk ~s~
C) Emulsion concentrate The active substance can also be formulated as an emulsion concentrate in the following manner:
20 parts of active substance according to formula I, 70 parts of xylene, and parts of a mixture of a reaction product of an alkylphenol with ethylene oxide and calcium-dodecylbenzenesulphonate are mixed together. On dilution with water to the desired concentration, there is obtained a sprayable emulsion.
Other biocidal active substances or agents can be added to the described agents according to the invention.
Thus, the new agents may contain, in addition to the mentioned compounds of formula I, e.g. insecticides, fungicides, bactericides, fungistatics, bacteriostatics, nematocides or further herbicides for the broadening of the range of action, and also, if desired, fertilisers, trace elements, etc..
Claims (7)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Compounds of the formula I
(I) wherein R1 represents hydrogen or chlorine, and R2 represents ethyl, or tert.butyl.
(I) wherein R1 represents hydrogen or chlorine, and R2 represents ethyl, or tert.butyl.
2. The compounds according to formula I in Claim 1 wherein R1 represents hydrogen.
3. 1,1-Dimethyl-3-(3-ethyl-phenyl)-urea.
4. 1,1-Dimethyl-3-(3-tert.butyl-phenyl)-urea.
5. 1,1-Dimethyl-3-(3-ethyl-4-chlorophenyl)-urea.
6. Process for the preparation of ureas of formula I of Claim 1 comprising a) reacting an isocyanate of formula II
(II) wherein R1 and R2 have the meanings given under formula I, with dimethyl-amine, or b) if R1 is to be chlorine, reacting a compound of formula III
(I I I ) wherein R2 has the meaning given under formula I, with chlorine or with a chlorine-releasing compound.
(II) wherein R1 and R2 have the meanings given under formula I, with dimethyl-amine, or b) if R1 is to be chlorine, reacting a compound of formula III
(I I I ) wherein R2 has the meaning given under formula I, with chlorine or with a chlorine-releasing compound.
7. A method for the selective control of weeds in crops of useful plants, which comprises applying to an area where weeds have to be controlled an herbicidally effective, but for the crop not phytotoxic amount of a com-pound of formula I as defined in claim 1, or of a composition (or an agent) containing the same.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1105173A CH575208A5 (en) | 1973-07-30 | 1973-07-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1058217A true CA1058217A (en) | 1979-07-10 |
Family
ID=4369566
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA205,683A Expired CA1058217A (en) | 1973-07-30 | 1974-07-26 | Selective herbicidal phenylureas |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5042036A (en) |
| CA (1) | CA1058217A (en) |
| CH (1) | CH575208A5 (en) |
| DE (1) | DE2436108A1 (en) |
| ES (1) | ES428712A1 (en) |
| FR (1) | FR2245623B1 (en) |
| GB (1) | GB1473889A (en) |
| IL (1) | IL45269A (en) |
| ZA (1) | ZA744808B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110938019A (en) * | 2019-12-10 | 2020-03-31 | 江苏快达农化股份有限公司 | Continuous synthesis method of isoproturon |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2739349C3 (en) * | 1977-09-01 | 1980-03-13 | Basf Ag, 6700 Ludwigshafen | N-O-alkyl-phenyD-N'-methyl-N · methoxyureas and herbicides containing them |
| CA2549558C (en) | 1999-01-13 | 2010-08-31 | Bayer Corporation | Omega-carboxyaryl substituted diphenyl ureas as raf kinase inhibitors |
| US20020065296A1 (en) | 1999-01-13 | 2002-05-30 | Bayer Corporation | Heteroaryl ureas containing nitrogen hetero-atoms as p38 kinase inhibitors |
| EP1158985B1 (en) | 1999-01-13 | 2011-12-28 | Bayer HealthCare LLC | OMEGA-CARBOXY ARYL SUBSTITUTED DIPHENYL UREAS AS p38 KINASE INHIBITORS |
| US20090068146A1 (en) | 2005-10-31 | 2009-03-12 | Scott Wilhelm | Diaryl ureas and combinations |
| CN102603573B (en) * | 2012-02-15 | 2013-12-18 | 江苏快达农化股份有限公司 | Method for synthesizing raw fluometuron drug |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL36218A0 (en) * | 1970-02-27 | 1971-04-28 | Ciba Geigy Ag | 4-isopropylphenylureas,their manufacture and use in combating pests |
-
1973
- 1973-07-30 CH CH1105173A patent/CH575208A5/xx not_active IP Right Cessation
-
1974
- 1974-07-15 IL IL45269A patent/IL45269A/en unknown
- 1974-07-23 FR FR7425479A patent/FR2245623B1/fr not_active Expired
- 1974-07-26 DE DE2436108A patent/DE2436108A1/en not_active Withdrawn
- 1974-07-26 CA CA205,683A patent/CA1058217A/en not_active Expired
- 1974-07-29 ZA ZA00744808A patent/ZA744808B/en unknown
- 1974-07-29 GB GB3341174A patent/GB1473889A/en not_active Expired
- 1974-07-29 ES ES428712A patent/ES428712A1/en not_active Expired
- 1974-07-30 JP JP49087446A patent/JPS5042036A/ja active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110938019A (en) * | 2019-12-10 | 2020-03-31 | 江苏快达农化股份有限公司 | Continuous synthesis method of isoproturon |
| CN110938019B (en) * | 2019-12-10 | 2022-06-24 | 江苏快达农化股份有限公司 | Continuous synthesis method of isoproturon |
Also Published As
| Publication number | Publication date |
|---|---|
| CH575208A5 (en) | 1976-05-14 |
| ZA744808B (en) | 1975-08-27 |
| FR2245623A1 (en) | 1975-04-25 |
| FR2245623B1 (en) | 1978-11-24 |
| IL45269A (en) | 1978-01-31 |
| JPS5042036A (en) | 1975-04-16 |
| GB1473889A (en) | 1977-05-18 |
| IL45269A0 (en) | 1974-10-22 |
| ES428712A1 (en) | 1977-01-01 |
| DE2436108A1 (en) | 1975-02-13 |
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