CA1187888A

CA1187888A - Isothioureas and their use for controlling undesirable plant growth

Info

Publication number: CA1187888A
Application number: CA000411289A
Authority: CA
Inventors: Rolf-Dieter Acker; Hans Theobald; Bruno Wuerzer
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1981-09-17
Filing date: 1982-09-13
Publication date: 1985-05-28
Also published as: IL66782A0; EP0075205A2; DE3136891A1; EP0075205A3; BR8205397A; JPS5869859A; ZA826781B

Abstract

ABSTRACT OF THE DISCLOSURE: Isothloureaa Or the formula

Description

- 1 - O.Z. 0050~35~27 Isothioureas and their use for controlling undesirable plant gro~th The present invention relates to novel isothio-ureas, their preparation, herbicides ~hich contain these compounds as act;ve ingredients, and their use for con-trolling undesirable plant gro~th.
It has been disclosed that t~,N-dimethylisothio-ureas are acaricides and lep;doptericides (U.S~ Pa~ents 3,992,447 and 4,049,826). Compounds of thi~ class are alsc kno~n to exhibit herbicidal actions tGerman La;d-Open Application DOS 1,643,809, Netherlands Laid-Open Appli-cation 6,713,501 and aritish Patent ~45,808) and an algi-cidal action ~French Patent 1,524,675). A herbicidal action has also been observed in the case of O-alkylated ur~as and isothioureas (U.S. Patent 2,849,306).
~ e have found that ;sothioureas of the formula I

~--~ SR1

2-- O ~-N I N-R2 t I ) / ~ R
Y X

~hich represents the isomers of the formula Ia Z-o O -N I - N_R2 ~Ia) \ / l3 Y X

,~,~ .., and a formula Ib o--~ sRl /~
Z / O ~ N N \ (Ib) / \ R
Y X
and where X, Y and Z are identical or different and are each hydrogen, halogen, Cl-C4 alkyl, Cl-C4-alkoxy, C1-C4-haloalkyl, Cl-C~-haloalkoxy or Cl-C4-alkylthio, R is Cl-C7-al~yl, C3-C7-cycloalkyl, Cl-C4-haloalkyl, C2-C8-alkylthioalkyl, benzyl, benzyl substituted by halogen, C2-C~-alkenyl, C2-C4-haloalkenyl or C~-C4-alkynyl, or is Cl-C4-alkyl substituted by a hetero-cyclic radical selected from the group consisting of isoxazolyl, isoxazolyl substituted by a substituent selected from Cl-C4-alkyl and phenyl, thiadiazolyl, thiadiazolyl substituted by a substituent selected from Cl-C4-alkyl and phenyl, oxadiazolyl, and oxadiazolyl substituted by a substituent selected from C1 C4-alkyl and phenyl, or is aryloxy-Cl-C4-alkyl, R is hydrogen, Cl-C7-alkyl or C3-C7-cycloalkyl, and R is hydrogen or -Co-oR4, where R4 is Cl-C3-alkyl, with the proviso that when Z is chlorine, Y is hydrogen, X is hydrogen, R2 is alkyl and R3 is hydrogen, Rl is not alkyl and R and R3 are not simulta-neously hydrogen, as well as their agriculturally acceptable salts, possess a considerable selective herbicidal activity.
Particularly active compounds have proved to be those in which X is hydrogen, Y is hydrogen, fluorine or chlorine, Z
is hydrogen or chlorine, Rl is methyl which is substituted by an unsubsti-tuted or methyl-substituted isoxazolyl, thiadiazolyl or oxadiazolyl radical or by an unsubstituted or chlorine-substituted phenyl or trichloroethylene radical, R2 is methyl or acetoxy and R3 is hydrogen. Rl is, in particular,3-methyl-isooxazol-5-methyl.

- 3 ~ O.Z. ~050~35427 The novel compounds may be prepared by a) reacting a haloalkyl compound of the formu~a Nal-R~
~here R1 has the above meanin~s and Hal is halogen, ~;th a thiourea of the formula ~-o O ~-N-CS-NHR2 ~ I I I ) ~ 13 o_q R
Y X

~here X, Y, Z, R2 and R3 have the above meanings, or b~ reacting an isothiourea of the formula .._c SR~
\
Z_~ O .-~H-C=NH (IV) Y X

~here X, Y, Z and R1 have the above mean;ngs, ~ith a chloroformate of the formula Hal-C0-OR4 (y) ~here R4 has the above meaning and ~al is halogen, and, if required, then converting the resulting compound into a salt.
Reaction a) is carried out at from 0 to 150C, advantageously in the presence of a base. If no base is added, the end product is obtained in the form of a salt, ~hich may subsequently be converted into the base.
Process b) is carried out using about ~ 4 ~ O Z. 0050/35427 stoichiometric amounts of ehe reactants, ie. about ~.8-1.2 mo~es of compound ~Y per m~e of compound V. Advanta-geously, compound IV is introduced into an inert solvent~
and the base and the chloroformate are added at from -10 to +80C, preferably from 10 to 50C, whi~e stirring. To complete the reaction, stirring is continued for from 15 minutes to Z4 hours, preferably for from I to 5 hours, and the mixture is filtered off from undissclved material or, depending on the use of the base, the phases are separated, and the organic phase is dried and concen-trated. The product is purified by recrystallization or chromatography.
The isothioureas of the formula IY are present in the form of an equilibrium mixture, corresponding to the compounds of the formula I Ccf. formulae Ia and Ib).
Both processes may be carried out continuously or batchwise, under atmospheric or superatmospheric pressure, the former being preferred for simplicity.
The reactions are carried out in a solvent ~hich is inert under the reaction conditions. Examples of su;table solvents are water, alcohols, eg. methanol, ethanol, n-propanol, isopropanol, n-butanol, s-butanol and t-butanol, halohydrocarbons, in particular chlorohydro-carbons, eg. tetrachloroethylene~ 1,1,2,2- or 1,1,1,2-tetrachloroethane, dichloropropane, methylene chloride, dichlorobutane, chloroform, chloronaphthalene, dichlrJro-naphthalene, carbon tetrachloride, 1,1,1- or 1,1,2-tri-chloroethane, trichloroethylene, pentachloroethane, o-, m-and p-difluorobenzene, 1,2-dichloroethane, 1,1-dichloro-8~3~

~ 5 ~ O.Z. 0050/35427 ethane, 1,2-cis-dichloroethylene~ chlorobenzene, fluoro-benzene, bromobenzene, iodobenzene, o-, p- and m-dichloro-benzene, o-, p- and m-dibromobenzene, o-, m- and p-chloro-toluene and 1,2,4-trichlorobenzene, ethers, eg~ ethyl propyl ether, methyl tert.-butyl ether, n-butyl ethyl ether, d;-n-butyl ether, diisobutyl ether, diisoamyl ether, di-isopropyl ether, anisole, phenetole, cyclohexyl methyl ether, diethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, thioanisole and ~ dichloro-diethyl ether, nitrohydrocarbons, eg. nitromethane~ nitro-ethane, nitrobenzene, o-, m- and p-chloronitrobenzene and o-nitrotoluene, nitriles, eg. acetonitrile, butyronitrile, isobutyronitrile, benzonitrile and m-chlorobenzonitrile, aliphatic or cycLoaliphatic hydrocarbons, eg. heptane, pinane, nonane, o-, m- and p-cymene, gasoline fractions boiling ~ithin a ran~e from 70 to 190C, cyclohexane, methylcyclohexane, decalin, petroleum ether, hexane, naphtha, 2,2,4-trimethylpentane, 2,2,3-trimethylpentane, 2,3,3-trimethylpentane and octane, esters, eg. ethyl ace-tate, ethyl acetoacetate and isobutyl acetate, amides, eg.
formamide, methylformamide and dimethylformamide, and ketones, eg. acetone and methyl ethyl ketone, as well as mlxtures of the above. Advantageously, the solvent is used in an amount of from 100 to 2,000X by ~eight, pre-ferably from 20û to 700X by weight, based on the starting materials.
All conventional acid-binding agents can be used as the bases. Preferred examples are tertiary amines, alkaline earth metal compounds, ammonium compounds, alkali 7~8 - 6 - O Z. 0050/35427 metal compounds and mixtures of these. Ho~ever, zinc com-pounds may also be used. Speci~ic examples of basic com-pounds are potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, lithium hydroxide, lithium carbonate, sodium bicarbonate, potassium b;carbonate, calcium hydroxide, calcium oxide, barium oxide, magnesium hydroxide, magnesium oxide, barium hydroxide, calcium car-bonate, magnesium carbonate, m3gnesium bicarbonate, magne-sium acetate, zinc hydroxide, zinc oxide, zinc carbonate, zinc acetate, sodium formate, sodium acetate, trimethyl-amine, triethylamine, tripropylamine, triisopropylamine, tributylamine, triisobutylamine, tri-sec-butylamine, tri-tert.-butylamine, tribenzylamine, tricy~lohexylamine, tri-amylamine, diisopropylethylamine, trihexylamine, N,N-di-methylaniline, N,N-diethylaniline, N,N-dipropylaniline~
N,N-dimethyltoluidine, N,N-diethyltolu;dine, N,N-dipropyl-toluid;ne, N,N-dimethyl-p-aminopyridine, N,N-diethyl-p-aminopyridine, N,N-dipropyl-p-aminopyridine, N-methyl-pyrrolidone, N-ethylpyrrolidone, N-methylpiperidine, N-ethylpiperidine, N-methylpyrrolidine, N-ethylpyrrolidine, N-methylimidazole, N-ethylimidazole, N-methylpyrrole, N-ethylpyrrole, N-methylmorpholine, N-ethylmorpholine, N-methylhexamethyleneimine, N-ethylhexamethyleneimine, pyrridine, quinoline,y~-picoline, ~-picoline, ~ picoline, isoqùinoline, pyrimidine, acridine, N,N,N',N'-tetramethyl-ethylenediamine, N,N,N',N'-tetraethylethylenediamine, quinoxaline, quinazoline, N-propyldiisopropylamine, N,N' dimethyl~yclohexylamine, 2,6-lutidine, 2,4-lutidine, tri-furylamine and triethylenediamine.

~ 7 ~ O Z 0050/35427 Examples of other suitable acid-binding agents, in addition to the above inorganic ones, are sodium propion-ate~ sodium butyrate, sodium isobutyrate, po~assium for-mate, potassium acetate, potassium propionate, potassium butyrate, potassium isobutyrate, sodium methylate, sodium ethylate, sodium propylate, sodium isopropylate, sod;um butyLate, sod;um ;sobutylate, sod;um sec-butylate, sodium tert.-butylate, sodium ethyleneglycolate, sodium propylene-1,2-0lycolate, sodium propylene-1,3~glycolate, sod;um di-~thyleneglycolate, sodium triethyleneqlycolate, sodium di-propylene-1,2-glycolate, potassium methylate, potassium ke$hylate, potassium n-propylate, potassium isopropylate, potassium n-butylate, potassium isobutylate, potassium sec-butylate, potassium tert~-butylate, potassium meth-yleneglycolate, potass;um propylene-1,2-glycolate, po~as-sium propylene-1,3-glycolate, potass;um d;ethyleneglyco-late, potassium tr;ethyleneglycolate and potass;um dipro-pylene-1,2-glycolate.
The isothioureas of the formula I can be converted into their crop-toLerated salts by conventional processes Examples of acids which are suitable for salt formation are hydrohalic acids (HCl, HBr and HI), sulfuric ac;d, nitric acid, phosphoric ac;d, acetic acid, dodecylbenzene-sulfonic acid, formic acid, oxalic acid and phthalic acid.
The activity or the salt is attributable to the cat;on, so that any anion may be selected, provided that it does not cause any damage.
The Examples which follow illustrate the prepara-tion of the compounds of the formula I. Parts are by 38~

weight.

a) 76 parts of phenylthiourea, 855 parts of benzyl bromide and 100 parts of ethanol were combined, and the mixture was refluxed for 1 hour. It was cooled and then concentrated, giving 161 parts of 1-phenyl-2-benzyliso-thiourea hydrobromide of melting point 128-130C.
b) 300 parts of water were added to 160 parts of the compound obtained as described above, and saturated sodium carbonate solution was added until a pH of 9 was reached.
The crystalline residue was filtered off under suction and dried, giving 115 parts of 1-phenyl-2-benzylisothiourea of melting point 75-77C.
c) The compound obtained as described in b) was also prepared as follows 76 parts of phenylthiourea ana 85.5 parts of benzyl bromide in 300 parts of dichloroethane were initially taken. 22 parts of sodium ethanolate in 70 parts of methanol were run in at lO~C, and stirring was continued for 3 hours at from 30 to 40C. The mixture was filtered, the solvent was distilled off, the residue was taken up in methylene chloride and the solution was washed with water, dried and concentrated, giving 118 parts of 1-phenol-2-benzylisothiourea of melting point 74-76C.
15 parts of 1-phenyl-2-benzylisothiourea in 50 parts of methylene chloride were initially taken. 6.6 parts of chloroforma-te and a solution of 2.8 parts of sodium hydride in 7 parts of water were added simultaneously, a little at a time, and the temperature was kept at 10-15C.
The mixture was stirred for 3 hours at room temperature, the organic phase was separated off, washed with water, dried with sodium sulfate and then concentrated, and the residue was recrystallized from methanol.

~, 9 _ 14.2 parts of 1-phenyl-3-carboxymethyl-2-benzyl-isothiourea of melting point 98-99C was obtained.

a) 22.1 parts of 1-(4-chlorophenyl)-3-methylthiourea, 14.5 parts of 3-methyl-2-chloromethylisoxazole and 30 parts of ethanol were refluxed for 5 hours. The solution was cooled and then concentrated, and the residue was dried under the xeduced pressure from an oil pump. 36.1 parts of 1-(4-chlorophenyl)-2-(3-methylisoxazol-5-ylmethyl)-3-methyliso-thiourea hydrochloride of melting point 151-154C were obtained.
b) 29 parts of the salt obtained in this manner were dissolved in water, and saturated sodium carbonate solution was then added until the pH reached 9. The mixture was stirred for 15 minutes, after which the product was filtered off under suction and dried. 22.8 parts of 1-(4-chloro-phenyl)-2-(3-methylisoxazol-5-ylmethyl)-3-methylisothiourea of melting point 100-103C were obtained.
The following compounds of the formula Ia were (or may be) prepared by procedures similar to those described in Examples 1 and 2; it should be noted that, where R3 is H, these compounds are obtained as equilibrium mixtures with compounds of the formula Ib.
The following abhreviations are used in the Table:

- 10 - O.Z. 0050/35427 A: 2,6-dichlorobenzYl G: -CH2-CCl=CC12 _O
Il 11 B: -CH2-- N I: 4_fluorobenzYl o C: 4-chlorobenzyl K: 2,4-dichlorobenzyl i C3H7 L: 3-fluorobenzyl O_ Il 11 D: --CH2-o N
o N_N
N_N ll il ll ll M --CH2-- -CH3 C 2 \ /
O O

N_N N: --CH2--~
Il 11 11 11 (~3~ CH2-o . N o \ / \ /
S O

T: 1 C6H5 '7~
0 . Z . 0050/35247 X Y Z Rl R2 R3 Salt;~I.p. ~nD
.

4 ~ n 2 5 H C2CH3 - 75- 78 ~ A H C2CH3 - 180-182 6 H H F CH3 CH3 ~- HBr 7 " " " " " " - 4 8- 5 0 8 " " ~'Senzyl g ~ B CH3 EI
~ n ~ CH3 H C2CH3 11 H F H CH3 CH3 H _ 1. 5980 12 ~ n ~ n HI1 70 - 1 7 3 13 ~ benzyl 3 1~ 6208 14 ~ n ~ n HBr . 15 ~ n A CH3 ~1 _ 61- 63 16 " " " " " " ~Cl 65- 66 17 " ~ ,. HBr 18 " " " C CH3 " - 1. 6190 19 " " " " " " H3r 159-160 ~ B ~ - 58- 60 21 " " " " " " HCl 139-141 2 2 " " " D '' "
23 " " " E " "

25 ~ ~ n n ~ ~I HCl 26 ~ G CH3 ~ - ~Cl 1.6211 27 " " ~ _ _ 1. 6103 2 8 ~ n ~ CH3 H
29 F H H CH3 c~3 H
3o ~ benzyl CH3 H HBr - 12 - O.Z. 0050/35427 X Y Z Rl R2 R3 Sal t L~l . p . / nD

32 F H H R CH3 H HCl 34 " " " B 3 HCl 35 " " '' 36 " ~ ~ CH3 H C2CH3 37 H Cl H CH3 CH3 H HI
38 " "1~
39 " ~ R 3 HCl 41 n " " B 3 HCl 43 " " " CH H C2CH3 44 H HCl CH3 ~ C02CX3 -81- ~3 45 ,. n n D CH3 H HCl 46 " " " " " 1l _ 47 2 5 C'~3 X _1.5962 48 " " ~ benzyl CH3 H HBr1.6301 49 " " " " " " -1.6255 H HCl I CH3 H HBr159-160 51 " " " " " " -57- 58 52 ~ ~- ,- A CH3 H HCl183-185 53 ~ -80- 82 54 " " " ~ " " HBr184-186

5~ ~' 1'" " " " -1.6319 56 ~ 1-,. L ,. " HBr142-145 57 ~ 1'" " " " -1.6229 58 " " " allyl " " HBr1.6130 59 " " " " " " -1.6190 ~ 1- G ~ ,. HCl167-172 61 " " " 5 " " -1.6246 62 H Cl H CH3 CH3 H

_ 13 - o.Z~ 0050/35427 X Y Z R1 R2 R3 Sal~ i~.p. ~nD

63 H Cl H b~nzyl CH3 H
64 It " " B CH3 H HCl 65 ~ " "
66 " " " R " " HCl 67 " It ,. " " "
68 H 3 3 CH3 H _65- 68 69 ~t " " " " n HI175-178 70 " " 2 5 1.6306 71 ~ t benzyl " " HBr85- 88 72 " " ~t " " " _70- 72 73 n ~t ~t D
74 " " " R " " HCl 76 H H i-C3~7 CT~3 H C2CH3 -111-113 77 " " " CH CH3 H -73- 74 78 ~ ,- ,. HI183-185 79 " " " B CT~3 H XCl 80 " " " " " "
81 " " " R H H
82 H CF3 H CH3 CH3 H HI~22-123 83 " ll ~ - ,. " _1.6189 84 " " " R " " HCl 85 " " " B " " HCl 86 " " " " " "
87 H Cl Cl CH3 CH3 H HI168-170 88 " " " " " " -1.5301 89 " ~ n ,. H C2CH3 -91- 92 " " "benzyl " " 1.6035 91 " " " 3 " " -70- 75 92 " " "benzyl CH3 H HBr189-191 93 " " " ~ CX3 H HCl1.6205 ~0 X Y Z Rl R2 R3Salt M.p./nD
.
94 H Cl Cl B i-C3H7 H HCl 95 " " " " CH3 " - 110-114 96 ~ 3 7 HCl 97 l~ . B CH3 ~I HCl 97 " " " B CH3 ~I HCl 98 " " " ll 99 " " " D " "HCl viscous 100 " " " " " "- viscous 1 0 1 " " " ~ " " -102 " " " M " "
103 " " " benzyl " " HBr 104 " " " " " "
105 H Cl OCH3 CH3 CH3 H
106 " " " " " " HI
107 H " " " H C2CH3 108 " " " B CH3 H HC1 1 0 9 " " " " " "
110 " " " R " "

112 " " " " " " HI
113 " " " B CH3 H HC1 114 " " " ll 115 " " " R CH3 H
116 " " " CH3 H C2CH3 117 " Cl Cl N CH3 HHCl viscous 118 " " " " " " EIBr 119 " " " " " " - viscous 120 H H Cl 2 phenoxy- CH3 H HBr oil ethyl 121 E~ Cl Cl " CH3 H HBr oil 122 H Cl Cl " CH3 H _ oil 123 H Cl Cl T CH3 HHCl 154-156 124 H C1 Cl T CH3 H - 84-87 B~3 - 15 - o.z. 0050/35'~27 The action of isothioureas of the formula I, or herbicidal agents containing them, on the growth of unwanted and crop plants is demonstrated in greenhouse experiments.
The vessels employed were plastic flowerpots having a volume of 300 cm3, and which were filled with a sandy loam containing about 1.5% humus. In the case of rice treated postemergence, peat was added to ensure better growth. The seeds o~ the test plants were sown shallow, and separately, according to species. ~or the preemergence treatment, the active ingredients were applied to the surface of the soil immediately after the seeds had been sown~ The compounds were emulsified or suspended in water as vehicle, and sprayed through finely distributing nozzles. The application rate was equivalent to 3.0 kg of active ingredient per hectare. After the agents had been applied, the vessels were lightly sprinkler--irrigated to induce germination and growth and to activate the chemical agents. Transparent plastic covers were then placed on the vessels until the plants had ta~en root. m e cover ensured uniform germination of the plants, insofar as this was not impaired by the chemicals.

For the postemergence treatment, the plants were first grown in the vessels to a height of from 3 to 15 cm, depending on growth form, before being treated. For this treatment, either plants which had been sown directly in the pots and grown there were selected, or plants which had been grown separately as seedlings and transplanted to the experiment vessels a few days before treat-ment. The application rates for postemergence treatment varied from ingredient to ingredient, and were equivalent to 0.5, 1.0, 2.0 and 3.0 kg/ha active ingredient per hectare. No covers were placed on the vessels in this treatment.

~ 8 ~
- 16 - O.Z. 0050/35427 The pots were set up in the greenhouse - species from warmer areas at from 20 to 35C, and species from moderate climates at 15 to 25C. m e experiments were run for from 3 to 4 weeks. During this period, the plants were tended and their reactions to the various treatments assessed. The scale used for assessmenthas O to 100, 0 denotlng no damage or normal emergence, and 100 denoting nonemergence or complete destruction of at least the visible plant parts.
The plants used in the experiments were Amaranthus retro-flexus, Arachis hypogaea, Avena sativa, Cassia tora, Centauracyanus, Chenopodium album, Datura stramonium, Gossypium hirsutum, Hordeum vulgare, Ipomoea spp., Oryza sativa, Sesbania exaltata, Sida spinosa, Sinapis alba, Solanum nigrum, and Triticum aestivum.
The test results show that the compounds exhibit a consider-able herbicidal action on pre- and postemergence application, and are well tolerated by, or cause only slight damage to, various crop plants.
In investigations into the selective herbicidal action on preemergence application, for example compounds nos. 2a, 2b, 13, 16, 20, 21, 88 and 89 had a considerable herbicidal action and at the same time were well tolerated by cereals, e.g., oats.
On postemergence application, for example compounds nos. 13, 18, 20, 27, 88, 89, 90, 93, 95, 99, 120, 121 and 122 had an appre-ciable herbicidal action.
Compounds nos. 27 and 99, applied postemergence, exhibited a conslderable actlon on various broadleaved unwanted plants, and caused little or no damage to groundnuts and cotton.

- 17 - O.Z. 0050/35427 ~ urther, compound no. 93 combated a number of unwanted broadleaved plants and was completely (or almost completely) selective in various crops, such as groundnuts, cotton, rice, barley and wheat.
If certain crop plants tolerate the active ingredients less well, application techniques may be used in which the herbicidal agents are sprayed from sultable equipment in such a manner that the leaves of sensivitve crop plants are if possible not touched, and the agents reach the soil or the unwanted plants growing beneath the crop plants (post-directed, lay-by treatment).
In view of their good compatibility and the many application methods possible, the herbicides according to the invention may be used in a further large number of crop plants for removing un-wanted plant growth. Application rates may vary from 0.1 to 15 kg/ha and more.
To increase the spectrum of action and to achieve synergistic effects, the compounds of the formula I may be mixed and applied together with numerous representatives of other herbicidal or growth-regulating active ingredient groups. Examples of suitable mixture components are diazines, 4H-3,1-benzoxazine derivatives, benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates, thiolcarbamates, halocarboxylic acids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils, benzofuran derivatives~
cyclohexane-1,3-dione derivatives, etc.
It may also be useful to apply the compounds according to the invention, either alone or in combination with other herbicides, in admixture with other crop protection agents, e.g., agents for combating pests or phytopathogenic fungi or bacteria. The com-pounds may also be mixed with solutions of mineral salts used to 7~ ~ 8 - 18 - O.Z. 0050/35427 remedy nutritional or trace element deficiencies. Non-phytotoxic oils and oil concentrates may also be added.
The agents according to the invention may be applied as con-ventional formulatlons, e.g. solutions, emulsions, suspensions, dusts, powders, pastes and granules. m e forms of application depend entirely on the purpose for which the agents are to be used, but must at all events ensure a fine and uniform distribu-tion o~ the active ingredient. The formulations are prepared in conventional mannerJ e.g., by extendlng the active ingredient with solvents and/or carriers, if desired using emulsifiers and dis-persants. Where water is used as diluent, other organlc solvents may also be employed as auxiliary solvents. Suitable compounds for preparing such formulations are solvents such as aromatics (e.g., xylene, benzene), chlorinated aromatics (e.g., chlorobenzenes), paraffins (e.g., petroleum fractions), alcohols (e.g., methanol, butanol), amines (e.g., ethanolamine, dimethylformamide), and water; carriers such as natural rock flours te.g., kaolins, diatomaceous earth, talc, chalk) and synthetic rock flours (e.g., highly disperse silicic acid, silicates); emulsifiers such as nonlonic and anionic emulsi~ying agents (e.g. polyoxyethylene--fatty alcohol ethers, alkyl sulfonates and aryl sulfonates); and dispersants such as lignin, sulfite waste liquors and methyl cellulose. The compounds according to the invention are preferably applied in aqueous solution, if desired with the additlon of water--miscible organic solvents, such as methanol or other lower alcohols, acetone, dimethylformamide or N-methylpyrrolidine. The ~ormulations generally contain from 0.1 to 95, and preferably from 0.5 to 90, wt% of active lngredient.

7B~
- 19 - O.Z. 0050/35427 The agents the ready-to-use formulations made therefrom, e.g., solutions, emulsions~ suspensions, powders, dusts, pastes or granules, are applied in known manner, ~or example preemergence, postemergence, or as seed disinfectants.
Examples of formulations are given below.
I. 20 parts by weight of the compound of Example 13 is well mixed with 3 parts by weight of the sodium salt of diisobutyl-naphthalene-alpha-sulfonic acid, 17 parts by weight of the sodlum salt of a lignin-sulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquor is obtained containing 0.1% by weight of the active ingredient.
II. 3 parts by weight of the compound of Example 27 is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing 3% by weight of the active ingredient.
III. 30 parts by weight of the compound of Example 26 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface o~ this silica gel. A formula-tion of the active ingredient is obtained having good adherence.
IV. 40 parts by weight of the compound of Example 21 is intimately mixed with 10 parts of the sodium salt of a phenol-sulfonic acid-urea-formaldehyde condensate, 2 parts o~ silica gel and 48 parts of water to give a stable aqueous dispersion. Dilu-tion in 100,000 parts by weight of water gives an aqueous dis-persion containing 0.04 wt~ of active ingredient.

- 20 - O.Z. 0050/35427 V. 20 parts of the compound of Example 15 is intlmately mixed with 2 parts of the calcium salt of dodecylben~enesulfonic acid, 8 parts of a fatty alcohol polyglycol ether, 2 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate and 68 parts of a paraffinic mineral oil. A stable oily dispersion is obtained.
VI. 90 parts by weight of the compound of Example 801s mixed with lO parts by weight of N-methyl-alpha-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.
VII~ 20 parts by weight of the compound of Example 29 is dissolved in a mixture consisting of 80 parts by weight of xylene, lO parts by weight of the adduct of 8 to 10 moles of ethylene oxide and l mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide and l mole of castor oil. By pouring the solution into lO0,000 parts by weight of water and unlformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.
VIII. 20 parts by weight of the compound of Example 13 is dis-solved in a mixture consisting of 40 parts by weight of cyclo-hexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide and l mole of isooctyl-phenol, and lO parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and finely distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

,rj~B~3 - 21 - O.Z. 0050/3~l~27 IX. 10 parts by weight of the compound of Example 93, 20 parts by weight of polyoxyethylene sorbitan monolaurate, 20 parts by weight of methanol and 50 parts by weight of water are stirred, giving a solution containing lOwt% of the active ingredient. More dilute solutions may be prepared by adding more water.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Isothioureas of the formula (I) which represents the isomers of the formula Ia (Ia) and of the formula Ib (Ib) and where X, Y and Z are identical or different and are each hydrogen, halogen, Cl-C4-alkyl, Cl-C4-alkoxy, Cl-C4-haloalkyl, C1-C4-haloalkoxy or C1-C4-alkylthio, R1 is Cl-C7-alkyl, C3-C7-cycloalkyl, Cl-C4-haloalkyl, C2-C8-alkylthioalkyl, benzyl, benzyl substituted by halogen, C2-C4-alkenyl, C2-C4-haloalkenyl or C2-C4-alkynyl, or is Cl-C4-alkyl substituted by a hetero-cyclic radical selected from the group consisting of isoxazolyl, isoxazolyl substituted by a substituent selected from Cl-C4-alkyl and phenyl, thiadiazolyl, thiadiazolyl substituted by a substituent selected from Cl-C4I-alkyl and phenyl, oxadiazolyl, and oxadiazolyl substituted by a substituent selected from Cl-C4-alkyl and phenyl or is aryloxy-Cl-C4-alkyl, R2 is hydrogen, Cl-C7-alkyl or C3-C7-cycloalXyl, and R3 is hydrogen or -CO-OR4, where R4 is Cl-C3-alkyl, with the proviso that when z is chlorine, Y is hydrogen, X is hydrogen, R2 is alkyl and R3 is hydrogen, R1 is not alkyl and R2 and R3 are not simulta-neously hydrogen, and agriculturally acceptable salts of these isothioureas.

2. Isothioureas of the formula I as claimed in claim 1, wherein X is hydrogen, Y is hydrogen, fluorine or chlorine, z is hydrogen or chlorine, Rl is methyl which is substituted by an unsubstituted or methyl-substituted isoxazolyl, thiadiazolyl or oxadiazolyl radical or by an unsubstituted or chlorine-substituted phenyl or trichloroethylene radical, R2 is methyl or acetoxy and R3 is hydrogen.

3. Isothioureas of the formula I as claimed in claim 2, wherein R1 is 3-methyl-isoxazol-5-yl-methyl.

4. A process for combating the growth of unwanted plants, wherein the plants and/or their location are treated with a herbicidal effective amount of a compound of the formula I as defined in claim 1.

5. A process for preparing compounds of the formula I as defined in claim l, wherein a) a haloalkyl compound of the formula Hal-Rl (II) where Rl has the meanings given in claim l and Hal is halogen, is reacted with a thiourea of the formula (III) where X, Y, Z, R2 and R3 have the meanings given in claim l, or b) an isothiourea of the formula (IV), where X, Y, Z and Rl have the meanings given in claim l, is reacted with a chloroformate of the formula Hal-CO-OR4 (V) where R4 has the meaning given in claim l and Hal is halogen, and, if required, the resulting compound is then converted into an agriculturally acceptable salt.