IL32632A - 1,3,4-thiadiazolyl ureas,their preparation and use as herbicides - Google Patents

Description

1,3,4-THIADIAZ0L*2. UREAS, THEIR PREPARATION AND USE HERBICIDES AGRIPAT S.A.

C: 30786 . , - - .. _ 32632/5 The present invention concerns new 1 , 3 , 4-thiadiazolyl-(2) -ureas, processes for the production thereof, futhermore, her bicidal agents containing such ureas as active ingredients, and methods for the control of weeds and wild grasses using the novel active substances or agents containing them.

The novel 1, 3, 4-thiadiazolyl- (2) -ureas correspond to the Formula I: In this formula: R1 represents a C-j-Cg alkyl, C2-C6 alkenvl or C2~C6 alkynvl radical optionally substituted by a halogen atom, a ; C1~C4 alkoxy or a ci~C4 alkylthio radical^ or a C^--Cg cycloalkyl radical; R2 represents a C-^-Cg alkyl, C^-Cg alkenyl or Cj-C cycloalkyl radical or, when ^ is other than alkyl, R2 may also be a hydrogen atom; R-j represents hydrogen or"a lower alkyl radical having at most 6 carbon atoms, mono-or R^ represents a C-j-Cg alkyl or a/polycycloalkyl radical, optionally - la substituted by a halogen atom or by a ©^*®^ alkoxy or C^-C^ alkylthio radical, o a lower alkoxyiadical having at most 10 carbon atoms.

In the general formula I, Jt^ Eg and as lower alkyl radicals are straight-chain or branched^chain radicals, such as the methyl, ethyl, n*pr©pyl» isopropyl, n-butyl, sec-butyl, tert-butyl and isobutyl radicals as well as pentyl and hexyl radicals. Furthermore R^, Rg and may also be @g to ®g alkenyl and alkynyl radicals, e.g. the ally! or mehallyl radical, or a propenyl, propynyl, (propargyl) or alkylpropynyl adical. Such aliphatic hydrocarbon radicals, in the case of and E^, can be substituted by a halogen atom, such as fluorine, bromine or iodine, or by a lowe alfco^ or alieylthi© radical. and Kg may also represent monocyclic, eycloalkyl radicals, having at most 6 Mta atome, while ¾ m» a aono- or p*¾r-cyclic eycloalkyl radical and have up to 10 carbon atoms* The following radicals are exampless cyclopropyl, l-methylcyelo-propyl, cyclobutyl, oyclopentyl, cyelohexyl, eycloheptyl, cyclooctyl, bicyelohexyl, bieycloheptyl, bicycloootyl, tri-eyelononyl, tetraeyclononyl.

The novel l,3,4-thiadiaz0lyl«-(2)-ureas of formula are produced according to the present invention by converting a 2-amlno««l, ,4-thiadiaaole of the formula II: \ either with a halogen carbonic acid ester or with phosgene in the presence of an acid-binding agent into a carbamic acid derivative and reacting this with an amine of the Formula III: •R, NH (i ) ^R4 wherein R-^, R2, R3 and R^ are as defined under Formula I.

As halogen carbonic acid esters, preferably chlorocarbonic acid phenyl esters and chloro-thiocarbonic acid phenyl esters are acid N- [ 5-thi.o-l, 3, 4-thiadiazolyl- (2) ] -carbamoyl-chloride , in almost quantitative yields.

Halogen carbonic acid esters and thiocarbonic acid-phenyl esters are known or can be produced by known methods. Compare: D.G. Crosby et al. [ J. Am. Chem. Soc . 76., 4458 (1954)].

As acid-binding agents, preferably tertiary amines such as trialkyl amines, pyridine bases, etc., furthermore hydroxides and oxides of alkali and alkaline earth metals are employed.

The reaction temperatures lie between 0 and 150°C. The reaction of such carbamic acid derivatives with a primary or secondary amine of Formula III is performed at temperatures between -40 and 150°C, preferably between 0 and 100°C. The urea derivatives according to the invention are obtained in good yields and high purity. The novel compounds are stable and soluble in conven- tional organic solvents, they are, however, sparingly soluble in water .

The 1, 3, -thiadiazolyl- (2) -ureas of Formula I in which represents hydrogen are produced by a modification of the process according to the invention by reacting a 2-amino-l, 3,4- thiadiazole of Formula II with an isocyanate of Formula II with an isocyanate of the Formula IV: R -NCO (IV) wherein is as defined under Formula I.

The processes described are performed in the presence of solvents or diluents which are inert to the reaction components.

The following are, for example, suitable: aliphatic and aromatic hydrocarbons and halohydrocarbons such as benzene, toluene, xylene, chloroform, chlorinated ethylenes; N, -dialkylated amides such as dialkylformamides ; ether and ether-type compounds; higher ketones such as methyl-ethyl ketone; etc.

According to a further modification of the present invention, the novel 1, 3, 4-thiadiazolyl- (2) -ureas of Formula I are obtained by reacting a 5-mercapto-l, 3, 4-thiadiazolyl-urea of the Formula V . wherein B represents hydrogen, the sodium or potassium ion or the equivalent of an alkaline earth metal ion, and with a halide of the Formula VI, Rj_ - Hal. (VI) In this formula Hal represe'nts chlorine, bromine or iodine, and R-j^ has the meanings given for Formula I.

This reaction is optionally performed in the presence of. bases and in the presence of solvents or diluents which are inert towards the reaction components. The reaction temperatures lie in the range of from 0 to 150°C, preferably between 20 and 100°C. Instead of the esters of hydrohalic acids (VI) , the corresponding esters of other acids, e.g. esters of sulfuric acid such as di-alkyl sulfates or esters of aromatic sulfonic acids such as o-toluene sulfonates can also be employed.

Furthermore, the novel 1, 3 , -thiadiazolyl- (2) -ureas can be obtained by reacting a 2-amino-l, 3 , -thiadiazole of Formula II with a carbamoyl halide of the Formula VII wherein in the presence of acid-binding agents.

The starting materials' f Formula II can be produced by known methods, for example by reacting the appropriately substituted thiosemicarbazides with carbon disulfide in pyridine and then reacting the resulting 2-amino-5-mercapto-l , 3 , 4-thiadiazole with a compound of Formula VI RL - Hal. (VI) [L.L. Bambas, the Chemistry of Heterocyclic Compounds, page 143 ff, (1952)]. The Formula II of the starting materials em viously not been described. The 5-mercapto-l, 3,4-thiadiazolyl- ureas of Formula V are new and can be obtained from 2~amino~5-mercapto-1, 3, 4-thiadiazoles by reacting the amino group (a) with a halogen carbonic acid phenyl ester or phosgene and an amine of Formula III or (b) with an isocyanate of Formula IV. Some of the 2-amino-5-mercapto-l, 3, 4-thiadiazoles of Formula II as well as some of the 5-mercapto-l, 3,4-thiadiazolyl-ureas of Formula V have microbiocidal properties.

The novel l,3,4-thiadiazolyl-(2) -ureas of Formula I have excellent herbicidal properties and can be employed for the control of mono- and dicotyl weeds and wild grasses. The urea derivatives of Formula I in which at least one of R or is hydrogen have especially good herbicidal activity. In high concentrations, the new ureas have especially good herbicidal activity. In high concentrations, the new ureas have a total herbicidal effect, in lower concentrations they have a selective herbicidal effect. The action of these substances includes the types of weeds which are difficult to control as well as the deep rooted types, e.g. leguminous and umbelliferous plants. They can be applied with equal success before (preemergence) and after emergence (postemergence) of the plants. Thus field weeds, such as types of millet (Pa-nicum sp.), types of mustard (Sinapis sp.), types of goose foot (Chenopodiaceae) , field foxtail (Alopecurus agrestis), types of chamomile (matricaria sp.), can be destroyed or their growth can be hindered without damaging cultivated plants such as grains, etc.

The following 1, 3, 4-thiadiazolyl ureas are used as test compounds to determine their herbicidal activity: N- [5-methylthio—1, 3, -thiadiazolyl- (2) ] -Ν,Ν' -dimethyl-urea N- [5-methylthio-l, 3, 4-thiadiazolyl- (2) ] -N' -methyl-urea, N- [5-prop nylthio-l, 3, 4-thiadiazolyl- (2) ]-N' -methyl-urea, N-[5-(2'-chloroallylthio)-l,3,4-thiadiazolyl-(2) ]- ' -methyl-urea, N- [5- (2' -chloroallylthip) -1 , 3 , 4-thiadiazolyl- (2) ] -N' ,Ν' -dimethyl-urea, N- [ 5-isopropylthio-l, 3, 4-thiadiazolyl- (2) ] -N1 -methyl-urea, N- [5-methylthio-l, 3, 4-thiadiazolyl- (2) ]-N' ,Ν' -methyl-urea, N- [ 5-methylthio-l, 3, 4-thiadiazolyl- (2) ] -N-cyclopropyl-urea, N-[5-methylthio-l,3,4-thiadiazolyl-(2) ]-N,N' -diethyl-urea, N- [5 >fethylthio-l, 3, 4-thiadiazolyl- (2) ] -N-methoxy-N' -methyl-urea, N-[5-isopropylthio-l,3,4-thiadiazolyl-(2) ]-N' ,Ν' -dimethyl-urea, N-[5-(2' -ethoxyethylthio) -1, 3, 4-thiadiazolyl- (2) ]-N' -methyl-urea, N- [ 5- (3 ' -iodoprop^-nylthio) -1,3, 4-thiadiazolyl- (2) ] -N1 -methyl-urea, N-[5-(2' -chloroallylthio) -1,3, 4-thiadiazolyl- (2) ]-N' ,Ν' -dimethyl-urea, N- [ - (2' -ethoxyethylthio) -1 ,3, 4-thiadiazolyl- (2) ] -N1 ,Ν' -dimethyl-urea, N- [ 5-methylthio-l, 3, 4-thiadiazolyl- (2) ] - 1 -methyl-N' -n-butyl-urea, N-[5-allylthio-l, 3, 4-thiadiazolyl- (2) ]-N' -methyl-urea, N-[5-ethylthio-l, 3, 4-thiadiazolyl- (2) ]-N' -methyl-urea, N- [5-methylthio-l, 3, 4-thiadiazolyl- (2) ]-N' -cyclopropyl-urea, N-[ 5-methylthio-l, 3, -thiadiazolyl- (2) ]-N' -allyl-urea, N- [5-allylthio-l, 3, 4-thiadiazolyl- (2) ]-N' ,Ν' -dimethyl-urea, N- [5-methylthio-l, 3, 4-thiadiazolyl- (2) ]-N' -methyl-N' - (3 ' -but n-2-yl) -urea. a) Germination test Method: The active substance is mixed with an inert carrier (talcum) in a ratio of 1:9 and the resulting 10?o-formulation is mixed with garden soil. The active substance is applied in a concentration of 0.5 g per liter of soil. The soil is filled into flower pots, and oats, ray grass, mustard and vetch are sowed therein. The results observed 20 days after sowing are expressed according to the following values: = normal growth 9-1 = graduated increase in damage 0 = all plants destroyed. b) Contact test Method : Flowerpots filled with soil are sowed with oats and mustard. The active substance is applied in the form of an emulsion prepared from a 25 emulsion concentrate. The concentration is 0.5 g of active substance in 100 ml of water per 2 m . The treatment is effected when the mustard reaches the 4 -6 leaf stage. The results are observed 14 days after treatment and are expressed as above under a) .

Results of germination and contact tests Germination test (effect Contact test (effect active after 20 days) after 14 days) substance oats ray grass mustard vetch oats mustard 1 0 0 0 0 2 0 2 0 0 0 0 3 0 3 0 0 0 0 - - Germination test (effect Contact test (effect active after 20 days) after 14 days) substance oats ί ray grass j mustard vetch oats mustard 0 0 0 0 1 0 6 0 0 0 0 - - 7 0 0 0 0 7 0 8 0 0 0 0 7 0 9 0 0 0 0 - - 10 0 0 0 0 4 0 11 0 0 0 0 7 1 12 0 0 0 0 3 2 13 1 0 0 2 - - 14 0 0 0 0 0 0 0 0 0 0 1 0 16 0 0 0 1 2 0 17 0 0 0 1 1 0 18 0 0 0 0 1 0 19 0 0 0 0 - - 20 0 0 0 0 - - 21 0 0 0 2 - - 22 1 0 0 2 — Preemergence- test iivith oats Method: The test plant (oat) is sown into a freshly prepared seed bed. Hereupon the active substance to be tested is applied to the bed as an aqueous dispersion prepared from a 25 °L wettable powder in a ratio of 110 ml dispersion per square meter of soil. Autochton weeds are: Chemopodium album, Polygonum pers., Capsella bursa past., Sinapis ar .

Result: The phytotoxic activity is determined both for cultivated plants and weeds 62 days after application of the active substance. j Concentra ion of active substance in kg/100 m2 3 2 1 Herbicidal action N- [ 5-methylthio-l, 3,4- 95% 90% 90% in 7o on the autoch- thiadiazolyl-(2) ]-N,N'- ton weeds dimethyl-urea N- [ 1, 3-Benzthiazolyl- 30% 0% 0% (2) ] -N' -methyl-urea (known from the US Patent No. 2,756,135) Phytotoxic action N- [ 5-Methylthio~l, 3,4- 2 2 2 on oat thiadiazolyl- (2) ] -Ν,Ν' - dimethyl-urea N- [ 1, 3-Benzthiazolyl- (2)]- 1 1 1 N1 -methyl-urea (known from the US Patent No. 2,756,135) Conclusion The known herbicide shows when applied at the same concentration no or only slight phytotoxic action on oat and weeds while the active substance according to this invention posesses an excellent selective herbicidal activity.

In the following 3 tests the compounds listed below are used as active substance: I N-[ 5-methylthio-l, 3, 4-thiadiazolyl- (2) ]-N,N' -dimethyl- urea (according to this invention) II N- [5-methylthio-l, 3, 4-thiadiazolyl- (2) ] -N' -methyl-urea (according to this invention) III N- [ 1, 3-benzthiazolyl- (2) ] - ' -methyl-urea (known from the US-Patent No. 2,756,135) IV N- [3~trifluoromethylphenyl] ~N' ,Ν' -dimethyl-urea (known from the Belgian Patent No. 594,227) V N- (3, 4-dichlorophenyl) -Ν' ,Ν' -dimethyl-urea (known from the US-Patents 2,655,444 - 447) Preemergence-test with lin Method : The test plant (lin) is sown into a freshly prepared seed bed. Hereupon the active substance to be tested is applied to the bed as an aqueous dispersion prepared from a 25 7. wettable powder in a ratio of 110 ml per square meter of soil. Autochton weeds are: Chenopodium album, Polygonum pers., Capsella burs. past. Sinapis arv.

Result : The phytotoxic effect on both, the cultivated plant and the weeds is determined 32 days after application of the active substance. known substances at the applied concentration show no phytotoxic effects on lin but they do not or only insufficiently control the autochton weeds. The compounds according to this invention show a very good action against the weeds and are equally compatible with lin.

Herbicidal action on vzeeds in preemergence application Test plants: Galium apar., Pastinaca sat., Sinapis alba, Vicia sat.; the autochton weeds are not considered.

Method: The above mentioned seeds are sown into a freshly prepared seed bed. The active substance to be tested is applied to the bed as an aqueous suspension, prepared from a 25 % wettable powder directly after sowing in such a manner that 200 or 100 ml of suspension are used per square meter.

Result: The herbicidal action was ascertained 34 days after the application. Known herbicides are also applied for comparison.

Conclusion: In this test, the compounds according to this invention proved to be superior for combatting the planted problem weeds over the known herbicides.

- - Herbicidal action on weeds in maize in postemergence application Method : The problem weeds Galium apar. and Pastinaca sat. together with maize as the plant to be cultivated are sown into a freshly prepared seed bed.

The active substance was sprayed as an aqueous suspension, prepared from a 257. wettable powder onto the seed- _ ·. bed 22 days after emergence of the plants. The autochton weeds .were Chenopodium album, Polygonum pers., Capsella bursa past., Sinapis arv.

Result: The phytotoxic action on the cultivated plant and on the sown weeds as well as the herbicidal action .on the autochton weeds were evaluated 31 days after application of the substaice to be tested. Known herbicides were used in this test in order to compare the results.

Active substance ! Herbicidal Phytotoxic action Conclusion ; Only the compounds according to this invention show the desired herbicidal effect in maize cultures^ in this test- Total herbicidal test Method : A meadow having a lot of weeds is treated in the middle of summer with an aqueous dispersion of the active substance, prepared from a 25 °L wettable powder. The concentration is so cal¬ Result : The herbicidal effect is evaluated after 98 days. Known herbicides are tested for comparison.

Conclusion: 2 An application of only 4 kg/100 m of the substance ac cording to this invention causes an excellent long lasting her bicidal effect which is achieved when 4 to 5 times the amount the known substances are applied.

The active substances according to the invention are tolerated by grains. Only in application amounts above 10 kg/ha of active substance does the severe ..damage., become evident, ... , which was already evident by using application amounts of 2 kg/ha and less of the urea derivatives in commercial use: N-phenyl-N' ,Ν' -dimethyl-urea (Fenuron) and N-3 , 4-dichloro- phenyl-N' , ' -dimethyl-urea (Diuron).

For the preparation of herbicidal agents, the active substances are mixed with suitable carriers and/or dispersing agents. To widen the range of action, these agents can be ad halogen-diamino-s-triazines , alkoxy- and alkylthio-diamino- s-triazines, triazoles, diazines such as uracils, aliphatic carboxylic acids and halogen carboxylic acids, halogenated benzoic acids and phenylacetic acids, aryloxyalkane' carboxyli acids, hydrazides, amides, nitriles, esters of such carboxyli acids, carbamic acid esters and thiocarba ic acid esters, ureas, etc.

Representatives of such herbicidally active substances v/hich can be admixed are, e.g., the following compounds: 2-chloro- 4 , 6-bis-(ethylarnino) -s-triazine , 2-chlor0-4-ethylamino-6-i sopropylamino-s-triazine , 2-chloro-4 , 6-bi s- (methoxypropylamino) -s-triazine, 2-methoxy- , 6-bi s- ( i sopropylamino) -ε-triazine , 2-di ethylamino- -i sopropylacetamido-6-methoxy- s-triazine , 2-i sopropylamino- A-methoxypropylamino-6-methylthio- s-triazine 2-methyIthio- A , -bi s- ( i sopropylamino) -s-triazine , 2-raethylthio-4 , 6-bi s- ( ethylamino) -s-triazine , 2-methylthio- -ethylamino-6-i sopropylamino-s-triazine , ■ 2-methoxy-4-ethylamino-6-i sopropylamino-s-triazine-, 2-methoxy- , 6-bi s- ( ethylamino) -s-triazine . 2-chloro- , 6-bis- ( i sopropylamino) -s-triazine, -bromo- 3-sec-butyl -o-rnethyl-uraci1 , -amino-5-chloro-l-phenyl-pyridazone-( 6) , 3 , 6-dioxo-l ,2,3, 6-tetrahydropyridazine , dinitro-sec-butylphenol and salts thereof, pentachlorophenol and salts thereof, trichloroacetic acid and salts thereof, 2, 2-dichloropropionic acid and salts thereof, 2-chloro- ,K-diallylacetic acid amide, maleic acid hydrazide. 2,3,6-trichlorobenzoic acid and salt-s thereof, 2, 3 j 5 j 6-tetrachlorobenzoic acid and salts thereof, 2-methoxy-3, 5, 6-trichlorobenzoic acid and salts thereof, 2-methoxy-3 , 6-di chlorobenzoi c acid and salts thereof, 3-amino-2 , 5-dichlorobenzoic acid and salts thereof, 3-nitro-2,5-dichlorobenzoic acid and salts thereof, 2-methyl-3 , 6-dichlorobenzoic acid and salts thereof, 2 , 6-di chlorobenzonitrile , 2,6-dichlorothiobenzamide, ■ o 2, 3,6-trichlorophenylacetic acid and salts thereof, 2, -dichlorophenoxyacetic acid and salts thereof, 2, 4 , 5-trichlorophenoxyacetic acid, and salts and esters thereof, (2-inethyl-4-chlorophenoxy) -acetic acid,and salts and esters thereo , 2-( 2, 4 , 5-trichlorophenoxy) -propionic acid, and salts and esters thereof, 2- ( 2, 4 , 5-trichlorophenoxy) -ethyl- 2, 2-di chlor©.propionate , 4-( 2, 4-dichlorophenoxy) -butyric acid, and salts and esters thereof, o 4-( 2-methyl-4-chlorophenoxy) -butyric acid, and salts and esters thereof , 2 , 3, 6-trichlorobenzyloxypropanol , 4-amino-3, 5 , 6-trichloropicolinic acid, N 1 -cyclooctyl-N,N-dirnethyl-urea , 3-phenyl-l ,1-dirnethyl-urea , 3- (4 ' -chlorophenyl) -1 ,1-dirnethyl-urea, 3-(3' -trifluorornethylphenyl) -1 ,1-dirnethyl-urea, 3-( 3' , ' -dichlorophenyl) -1 , 1 -dimethyl -urea , 3-( 3 ' , 4 ' -dichlorophenyl) -1-n-butyl-l-methyl-urea,. o 3-(3* ,4' -dichlorophenyl) -1,1, 3-trimeth l-urea 3-(3' j 41 -dichlorophenyl) -1 ,1-diethyl-urea , 3-( ' -chiorophenyl ) -1-methoxy-l -methyl -urea, 3-( 3 ' , 41 -dichlorophenyl) -1-methoxy-l-methyl-urea, 3-( 4 ' -bromophenyl) -1-methoxy-l-methyl-urea, 3- ( 3 ' , 4 ' -dichlorophenyl ) - 3-methoxy-l , 1 -dimethyl -urea , 3-( 41 -chlorophenoxyphenyl) -1 ,1-dimethyl-urea, N ,N-di-(n-propyl) -S-ethyl-thiocarbamate , N,N-di-(n-propyl) -S-n-propyl-thiocarbamate , N-ethyl -N- (n-bu yl) -S-n-propyl-thiocarbamate , -phenyl -O-isopropyl- carbamate , -(m-chlorophenyl) -0-isopropyl -carbamate , N-(m-chlorophenyl) -0- -chloro-butyn- ( 2) -yl-carbamate , N-(3" , 4 ' -dichlorophenyl) -O-methyl-carbamate .

The following examples illustrate the process for th production of the new compounds of Formula I. V/here not stated otherwise, temperatures are expressed in degrees centigrade and parts and percentages are by weight.

Example 1 N-[ 5-me h lthio-1 , 3 , 4-thiadiazolyl- ( 2) ] -N ' -methyl -urea 44.2 parts of 5-methyithio-2-amino-l , 3. -thiadiazole (m.p. 177-178°) are dissolved in 200 parts of benzene and at room temperature added dropwise during 30 minutes to 19 parts of methyl isocyanate. The mixture is then stirred for 2 hours at 30 to 40°. After cooling, the precipitated product is filtered, washed with a little benzene and dried. N-[5-methylthio-1 , 3 , 4-thiadiazolyl-( 2) ] -N 1 -methyl -urea: m.p. 256° (with decomposition) .

The starting material is produced as follows: 91 parts of thiosemicarbazide are suspended in 1000 parts of pyridine and during 3/4 hour added dropwise to 120 parts of carbon disulfide. The mixture is then slowly heated to the boil and refluxed until all. of the material is dissolved. After the pyridine has been evaporated in vacuo, the crude residue is methylated in an ethanolic potassium hydroxide solution with methyl iodide. 5-Methylthio-2-amino-l , 3 , -thiadiazole (ca. 75-80 yield) , m.p. 177-178° (from water) , is obtained.

By using the appropriate 5-thio-2-amino-i , 3 , -thiadiazoles and equirnolar amounts, of the corresponding isocyanates, the compounds listed in Table 1 were obtained in the manner-described in the above example. 1. N-Omcthyl lhlo-1 , 3, - thl adlazoly l-(2>]-K-al lyl-N'-mcthyl-urea 2. N-[5-met y 1 thio-1 , 3, -thiadiazoly l-(2) ]-N-i sopropy 1-N '-methyl-urea 3. N— [ 5— methy 1 thio-1 ,3,4-thiadiazolyl-(2)]-N-cycl opropyl-N'-mcthyl-urea 4. N-[5-methyl thio-1, 3, A-thlad iazol y 1 -(2) ]-N-al 1 y 1 -N '-methy 1-urea . M-[5-(2'-ch1 oroal lyl thio)-l , 3, A-th i ad i a zo 1 y 1 - ( 2) ]-N , N '-d i me thy 1 -urea 6. N-[5-(2'-chl oroal lyl thi o)-l , 3, 4-t i adi azo) y 1 - (2) ]-N-i sopropy 1 -N ' -methy 1 -urea 7. N-[ 5-propargy 1 hio-1 ,3, 4-th i ad iazoly!-( ) ]- '-methyl -urea 8. N-[ 5-i sopropy 1 thio-1 ,3, -th iadiazolyl-(2)]-N'-met yl -urea 9. . N-[5-nethylthio-l,3,4-thiadiazolyl-(2)l-N-iBethyl-N,-oethyl-urea . N-[ 5-me thy 1 thio-1 ,3iA-thiadiazolyl-(2)]-N-cyclohexyl -N '-methy 1 -urea 11. N-[5-methyl thio-1 , 3, -thi ad i azol y 1 -( 2 ) ]-N '-al lyl-urea 12. N-[ 5-me thy 1 hio-1 , 3, 4-th i ad i azol 1 -(2) ]-N '-cycl opropyl -urea 13. N-[5-nethyl thio-1 ,3, 4-th iadi azol yl-( 2) ]-N '-cycl ohexyl -urea 14. ' N-[5-methyl thio-1 ,3, -thiadiazolyl-(2)]-N'-bicyclo[4,l,0]heptyl-urea . N-[ 5-meth 1 thio-1 ,3, 4-t iadi azol yl -(2) ]-N'-octahydro-methenopehtal enyl-urea 16. N-[5-methylthio-l,3,4-thiadiazolyl-(2)]-N'-P-chloroethyl-urea 17; N-[5-p-ethoxy-ethyl thio-1, 3, 4-thiadiazolyl-(2)]-N'-mcthyl-urea 18. N-[5-p-ethylthio-eihyl thio-1, 3, 4-th ad iazol y 1 -(2) ]- '-meth 1-urea 19. N-[5-al lyl hio-1, 3, 4-thi ad i a zol y 1 -{ 2) ]- ' , * -di methyl -urea . N-[-5-G'-iodopropargylthio)-l,3,4-thiadiazolyl-(2)]-N,N'-dimethyl-urea 21. N-[ 5-methy 1 thio-1, 3, 4-thiadiazol l -(2)]- '-β-methoxyethyl -urea 22. N-[5-methyl thio-1, 3, 4-th i ad i azo 1 y 1 -(2) ]-N '-β-methy 1 th i octhy 1 -urea 23. N-[ 5-cyc lohexyl thio-1 ,3,4-thiadiazolyl-{2)]-N '-methy 1 -urea 24. N-[5-(2'-chl oroal lyl thio)-l, 3, 4-thiadiazolyl-(2)]-N '-methyl-urea Ξ 1 2 N-L 5-methylthiο-1 , 3 , -thiadiazolyl- ( 2) ] -N ' , ' -dimethyl -urea 14.7 parts of 5-methylthio-2-amino-l , 3 , -thiadiazole and 10 parts of triethylamine are dissolved in 150 parts of chloroform, and at 0 - 5° with stirring are treated with 15.6 parts of phenyl chloroformate . Stirring is continued for 2 hours at 20°. The mixture is treated with ice water, thoroughly shaken, and the chloroform layer is separated, dried and concentrated. The residue is recrystallized in alcohol. 25.7 parts (96$) of phenyl N-[ 5-methylthio-l , 3 , 4-thiadiazolyl-( 2) ] -carbamate , rn.p. 171°, are obtained.

The carbamate obtained is suspended in 100 parts of benzene and refluxed. A weak stream of- 10 to 20 parts of dry dimethyla ine is conducted through the boiling mixture. After completion' of the reaction, the benzene is evaporated in vacuo. The residue is thoroughly stirred with cold water, filtered and then recrystallized from water. 13.6 parts (65^) of N-[ 5-methylthio-l , 3, -thiadiazolyl-( 2) ] -N ' , ' -dimethyl-urea , rn.p. 192-194°, are obtained.

In the manner described in this example, using the appropriate 1 , 3 , 4-thiadiazole and phenyl chlorocarbonate, the corresponding phenyl carbamates are obtained, from which by reacting with the appropriate secondary amines the following compounds listed in Table 2 were obtained.

TABLE 2 Compounds 1. N-[5-al lylihio-1 ,3, -thiadiazolyl-iZll-N^'-dimethyl-urea 2. N-[ 5-meihy lihio-l,3,4-thiadia2olyl-(2)]-N'-metny1-N*-] '-methyl-propynyl-urea 3. N- 5-tnethy 1 hi o-l ,3, Ί-thi a diazolyl-(2)]-N'-methyl-N'-methoxy-urea 4. N-[5-cyc]ohexylihio-l,3,4-thi3diazo!yl-(2)]-N',N'-diraethyl-urea . N-[5-(2t-chloroallyl hio)-l,3, -thiadiazolyl-(2)]-N*,N'-diethyl-urea Example 3 Ν-[ 5-ethylthio-l , 3 , 4-thiadiazolyl- ( 2) ] -Ν ' -rcethyl-urea 19 parts of N-[ 5-mercapto-l , 3 , 4-thiadiazolyl- ( 2) ] - 1 - methyl-urea (m.p.: 230-231° decomposition) are dissolved in 100 parts by volume of ethanol to which 4 parts of sodium hydroxide, di s solved in a little water, have been added. Then during 30 minutes, 15.6 parts of ethyl iodide are added drop- wise at 20° and the mixture is stirred for 2 hours at 50°.

The clear solution is evaporated to dryness, the residue is . slurried with 100 parts by volume of water and filtered. The N_[ 5-ethylthio-l , 3, -thiadiazolyl- ( 2) ] -N1 -methyl- urea is recrystallized from water ^ m.p. 194-196°.

Example 4 iH 5-methylthio-i , 3 , 4-thiadiazolyl- ( 2) ]- ' ,IT ' -diethyl-urea 200 parts by volume of chloroform are saturated with phosgene at 0 to 5° and, at the same temperature and simultaneously introducing phosgene, treated with 25 parts of -methylthio-2-amino-l , 3, 4-thiadiazole. The mixture is stirred for 3 hours at the same temperature and then evaporated to dryness under vacuum. The solid residue is suspended' in 200 parts by volume of benzene and, at 0 to 5°, treated with an excess of 2 to 3 times the amount of diethylamine (ca. 35 parts). The mixture is stirred for 3 hours at room temperature and the undissolved material is removed by filtration.

The filtrate is then evaporated to dryness under vacuum and the residue, namely N- 5-methylthio-l , 3 , -thiadiazolyl- ( 2) ] -1J ' ,N 1 -di ethyl-urea , is recrystallized from ethanol, m.p.

The production of herbicidal agents according to the invention is performed in a known manner by intimate mixing and grinding of active substances of the general Formula I together with suitable carriers, optionally with the addition of dispersing agents or solvents, which are inert towards the active substances. The active substances can be used ana applied in the following forms: solid preparations: dusts, scattering agents, granulates, coated granulates, impregnated granulates and homo- geneous granulates; water-dispersible concentrates of the active substance: wettable powders, pastes, emulsions; liquid preparations: solutions, aerosols.

For the production of solid preparations (dusts, scatter-ing agents, granulates) the active ingredients are mixed with solid carriers. The particle size of the carriers is from about 0.075 to 0.2 mm for dust s, and 0.2 mm or more for granulates . The concentration of active ingredient in the solid preparations is usually 0.5 to 80%. These mixtures can also contain additives which stabilize the active ingredient and/or substances which are non-ionic, or anionically or cationically active, which substances, for example, improve the adhesion of the active ingredients on plants or parts of plants (adhesives and agglutinant s) and/or ensure a better wetta-bility (wetting agents) and di spersibility (dispersing agents) .

I ι Ivater-dispersible concentrates of the active ~ub stance , wettable powders, pastes and err.uision ccncent rates , are agents which can be diluted with water to any desired concentration. They consist of active substance, carrier, optionally additives for stabilizing the active substance, surf ce-active substances and anti -foaming agents , and optionally solvents.

The concentration of active substance in these preparations is from 5 to c0¾. The wettable powders and pastes are obtained by mixing and grinding the active substances with dispersing agents and pulverulent carriers in suitable. equipment until the products are homogeneous. In some cases it is advantageous to use mixtures of different carriers.

The anti-foaming agents may, for example, be silicones.

The active substances are so mixed, ground, sieved and classified with the above-mentioned additives that in the wettable powders the solid fraction does not exceed a grain size of 0.02 to 0.04 and in pastes does not exceed 0.003 mm. Dispersing agents, organic "solvents and 'water are used for the preparation of emulsion concentrates and pastes. The solvents must be practically odorless, non-phytotoxic , inert towards the active substances and not easily combustible.

Furthermore, the agents according to the invention may be applied in the form of solutions. For this purpose, one or more of the active substances of the general Formula I is or are dissolved in suitable organic solvents, mixtures of solvents, or water. The concentration of the active substances contained in the solutions should be in the range of 1 to 20%. Other biocidal active substances or agents can be .L admixed with the agents described according to the invention. Thus, in addition to the said compounds of the general Formula I and other herbicides, the ne; agents ma contain, for example, insecticides, fungicides, bactericides, fungi -static and bacteriostatic substances or nematociaes in order-to broaden the range of action.

The agents according to the invention may also contain plant fertilizers, trace elements, etc.

Preparations containing the new ureas are described be- low. Parts and percentages are expressed by weight. - - i Granulate The following ingredients are used to produce a 5% granulate: parts of N- [ 5-methylthio-l , 3,4-thiadiazolyl-(2) ] -N- allyl-N' -methyl-urea, 0.25 part of epichlorohydrin, 0.25 part of cetyl polyglycol ether with 8 mols of ethylene oxide, 3.50 parts of polyglycol "Carbowax", molecular weight about 400, 91 parts of kaolin (particle size 0.3 - 0.8 mm).

The active ingredient is mixed with epichlorohydrin and dissolved with 6 parts of acetone, then the polyglycol and cetyl polyglycol ether are added. The resulting solution is sprayed onto kaolin and the acetone is then evaporated in vacuo.

Wettable Oo /der The following components. are used for the preparation of a) 50#, b) 25 and c) 10% vettable powders: a) 50 parts of N-[ 5-methylthio-l , 3 , -thiadiazolyl- (2) ]-N, ' -dimethyl-urea, parts of sodium dibutylnaphthyl sulfonate. 3 parts of naphthalene sulfonic acid/phenol sulfonic acld/formaldehyde condensation product 3:2:1, parts of kaolin, 22 parts of Champagne chalk; b) 25 parts of N- 5-methylthio-l , 3 , 4-thiadiazolyl- (2) ]-N' -methyl-urea, parts of the sodium salt of oleylmethyl tauride, 2.5 parts of naphthalene sulfonic acid/formaldehyde condensation product, 0.5 part of carboxymethyl cellulose, parts of neutral potassium aluminum silicate, 62 parts of kaolin; c) 10 parts, of N-[ propyn- ( 2) yl- ( 1) -thio-1 , 3 , 4-thia- diazolyl-( 2) ] -N ' -methyl-urea, 3 parts of mixture of sodium salts of saturated fatty alcohol sulfates, parts of naphthalene sulfonic acid/ ormaldehyde condensation product. 82 parts of kaolin.

The given active ingredient is absorbed onto the corresponding carriers (kaolin and chalk) and then mixed and ground. V/ettable powders having excellent wettability ana suspensibilit are obtained. By dilution with water, suspensions of any desired concentration of the active ingredients can be obtained from such v/ettable pov/ders. Such suspensions are suitable for the control of weeds and wild grasses in cultivated plantations .

Paste The following ingredients are used for the preparation of a 45 % paste: 45 parts of N- [5-methylthio-l, 3, 4-thiadiazolyl- (2) ] -N- allyl-N' -methyl-urea, parts of sodium aluminium silicate, 14 parts of cetyl polyglycol ether with 8 raols of ethylene- oxide (Genapol 0 080) , 1 part of cetyl polyglycol ether with 8 mols of ethylene- oxide (Genapol 0 050) , 2 parts of spindle oil, parts of polyglycol "Carbowax", molecular weight about 400, 23 parts of water.

The active ingredient is intimately mixed and ground in suitable equipment with the addititves. A paste is obtained which can be diluted with water to prepare suspensions of any desired concentration. These suspensions are suitable for the treatment of vegetable plantations.

Emulsion concentrate To prepare a 10%, emulsion concentrate parts of N- [ 5-propargylthio-l, 3, 4-thiadiazolyl- (2) ] - ' - methyl-urea, parts of oleyl polyglycol ether having 8 mol of ethylene oxide, and 75 parts of isophorone (3 , 5 , 5-trimethylcyclohex-2-en-l- are mixed together. This concentrate can be diluted with wate to emulsions of suitable concentrations. Such emulsions are suitable for the control of weeds in cultivated plants such as cotton, maize, for which purpose application of about 0.5 to 3 2 of a compound of Formula I per 100 m of soil is recommended.

Claims (10)

We claim:

1. , 3, 4-thiadiazolyl- (2)-urpas of the Formula I, wherein R1 represents a alkyl, Cg-Cg alkenyl or C2~C6 alkynvl radical optionally substituted by a halogen atom, a C-^-C^ alkoxy or a C-L""C4 &11ζν1ΐ 5-0 radic^or a C^-Cg cycloalkyl radical; represents a C^-Cg alkyl, Cg-Cg alkenyl or C.-,-Cg cycloalkyl radical or, when is other than alkyl, . , 1¾2 may also be a hydrogen atom; R-. ■ represents hydrogen or a lower alkyl radical having at most 6 carbon atoms, mono'-: or R^ represents' a C^-Cg alkyl or a/polycycloalkyl radical, optionally substituted by a halogen atom, or by a C-^-C^ alkoxy or C-^-C^ alkylthio radical, or a lower alkoxy radical having at 'most 10 carbon atoms.

2. · N-[ 5-Methylthio-l , 3 , 4-thiadiazolyl- ( 2 ) ]-N., ' -dimethyl-urea .

3. · N-[ 5-Methylthio-l, 3 , -thiadiazolyl- (2 ) ]-N' -methyl-urea'.

4. N-[Propyn-(2)-yl-(l)-thio-l,3 4-thiadiazolyl-(2)]-N,-methyl-urea.

5. Process for the production of 1, 3, -thiadiazolyl- (2) -ureas of the Formula I in Claim 1, character zed by converting a 2-amino-1, 3, 4-thiadiazole of the Formula II: either with a halogen carbonic acid ester or with phosgene in the presence of an acid-binding agent into a carbamic acid derivative and reacting this with an amine of the Formula III: whereby in the Formulas II and III, the symbols to have the meanings given for Formula I.

6. Process according to Claim 5, characterized by employing, as halogen carbonic acid ester, phenyl chlorocarbonate or phenyl chlorothiocarbonate.

7. Process for the production of 1, 3, ~thiadiazolyl- (2) -ureas of Formula I in which represents hydrogen, characterized by reacting a 2-amino-l, 3, 4-thiadiazole of Formula II in Claim 5 with an isocyanate of the Formula IV: R4 - NCO (IV) in which R^ has the meanings given for Formula I.

8. Process for the production of 1, 3, 4-thiadiazolyl- (2) -ureas of Formula I in Claim 1, characterized by reacting a 5-mer-capto-1, 3, 4-thiadiazolyl- (2) -urea of the Formula V, wherein B represents hydrogen, the sodium or potassium ion or the equivalent of an alkaline earth metal ion, and ]¾2, R^, R^ have the meaning given for Formula I, with a halide of the Formula VI wherein Hal represents chlorine, bromine or iodine, and R^ has the meanings given for Formula I.

9. A composition comprising a herbicidally active amount of d . at least one 1,3, -thiadiazolyl- (2) -urea as~ylfined in Formula I in Claim 1, together with dispersing agents and/or carriers suitable for the 'control of weeds and wild grasses and optionally other herbicides and biocidally active substances.

10. A method for the control of weeds and wild grasses, characterized by the application of a herbicidally effective amount of 1, 3, 4-thiadiazolyl- (2) -ureas of the Formula I in Claim 1 to such plants or the application of compositions according to Claim 9.