GB1582571A

GB1582571A - Herbicidally active 2-dimethylcarbamoylimino-1,3,4-thiadiazolin-3-ide salts process for their manufacture and their use

Info

Publication number: GB1582571A
Application number: GB19295/77A
Authority: GB
Original assignee: Schering AG
Current assignee: Bayer Pharma AG
Priority date: 1976-05-24
Filing date: 1977-05-09
Publication date: 1981-01-14
Also published as: IT1080397B; CH630234A5; EG12841A; NL7704219A; FR2352809B1; MX4627E; CS195333B2; PL198291A1; BR7702545A; ES458100A1; JPS52144671A; FR2352809A1; LU77391A1; RO72225A; FI64362C; FI64362B; DD129853A5; ATA370077A; SE422792B; IL52034A0

Abstract

The herbicidal composition contains at least one novel 2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide salt of the general formula I <IMAGE> in which R denotes an aliphatic hydrocarbon radical and B<(+)> denotes a monovalent metal equivalent, as at least one active ingredient. The compounds are distinguished, for example, by a broad soil- and leaf-acting herbicidal activity. They can be used for controlling mono- and dicotyledon weeds. Two preparation processes of the compounds of the formula I are defined in Patent Claim 17.

Description

(54) HERBICIDALLY ACTIVE 2-DIMETHYLCARBAMOYLIMINO-1,3,4 THIADIAZOLIN-3-IDE SALTS, PROCESS FOR THEIR MANUFACTURE AND THEIR USE (71) We, SCHERING AKTIENGESELLSCHAFT, a Body Corporate organised according to the laws of Germany, of Berlin and Bergkamen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention is concerned with new herbicidally active 2 dimethylcarbamoylimino-1,3,4-thiadiazolin-3-ide salts, with a process for the manufacture of these compounds and also with their use.

1-(1,3,4-Thiadiazol-2-yl)-urea derivatives having a herbicidal action are already known (German Offenlegungsschriften Nos. 1,816,696, 1,901,672 and 2,118,520). However, they have insufficient action against undesired plant growth in crop plantations.

The problem upon which the present invention is based has, therefore, been to provide a hebicidal agent which has an excellent action against weeds and also a wide spectrum of selectivity towards crop plants.

This problem is solved in accordance with the present invention by the compounds of the general formula I, as defined below.

The present invention accordingly provides componds of the general formula I

in which R represens an aliphatic hydrocarbon goup containing at least 2 carbon atoms, with the proviso that when R represents an alkyl group containing less than 5 carbon atoms, a methyl group is directly attached to the 1-position of the alkyl group, and B represents a monovalent metal equivalent.

The compounds of the present invention are distinguished by their broad soil-herbicidal and leaf-herbicidal action. They cap be used for combating mono- and di-cotyledonous weeds.

With the compounds of the present invention there are combated by pre-emergence and also by post-emergence methods agricultural weeds, for example Sinapis ssp., Stellaria media, Senecio vulgaris, Matricaria chamomilla, Ipomoea purpurea, Chrysanthemum segetum, Lamium amplexicaule, Centaurea cyanus, Amaranthus retroflexus, Alopecurus myosuroides, Echinochloa crus galli, Setaria italica, Sorghum halepense, Lolium perenne and Gallium aparine.

For combating seed weeds there are generally used rates of application of 0.5 kg of active substance per hectare to 5 kg of active substance per hectare. When two or more compounds of the general formula I are used the range of 0.5 to 5 kg refers of course to the total amount applied of these compounds. Thereby, the active compounds of the general formula I have proved to be selective in crops of useful plants, for example bush bean, ground-nut, potato, pea, maize, rice, sorghum and soya crops.

At higher rates of application the active compounds are also suitable as total herbicides for the destruction or suppression of waste land flora during a period of vegetation.

The present invention accordingly also provides a herbicidal preparation which comprises a compound of the general formula I, in admixture or conjunction with a suitable carrier.

The preparation may of course contain one or more compounds of the general formula I.

The present invention further provides a method of protecting a living plant against weeds, wherein the area in the vicinity of a living plant is treated with a compound of the general formula I.

The present invention further provides a method of protecting a crop area against weeds, wherein a crop area is treated with a compound of the general formula I.

The present invention further provides a method of protecting waste land against weeds, wherein the waste land is treated with one or more compounds of the general formula I, the compound(s) being used in a total amount of more than 5 kg per hectare.

The present invention further provides a pack which comprises a compound of the general formula I together with instructions for its use as a herbicide.

The compounds of the present invention may be used either alone, or in admixture with one another or with other active substances.

Depending on the purpose desired, there may be mentioned in this connection, for example, the following herbicidally active substances which may, if desired, be added to the compounds of the invention only immediately before use: substituted anilines, substituted aryloxycarboxylic acids and also salts, esters and amides thereof, substituted ethers, substituted arsonic acids and also salts, esters and amides thereof, substituted benzimidazoles, substituted benzisothiazoles, substituted benzthiadiazinone dioxides, substituted benzoxazines, substituted benzoxazinones, substituted benzthiazoles, substituted benzthiadiazoles, substituted biurets, substituted quinolines, substituted carbamates substituted aliphatic carboxylic acids and also salts, esters and amides thereof, substituted aromatic carboxylic acids and also salts, esters and amides thereof, substituted carbamoylalkyl-thio- or dithio-phosphates, substituted quinazolines, substituted cycloalkylamido-carbonthiolic acids and also salts, esters and amides thereof, substituted cycloalkylcarbonamido-thiazoles, substituted dicarboxylic acids and also salts, esters and amides thereof, substituted dihydrobenzofuranyl sulphonates, substituted disulphides, substituted dipyridylium salts, substituted dithiocarbamates, substituted dithiophosphoric acids and also salts, esters and amides thereof, substituted ureas, substituted hexahydro-lH-carbothioates, substituted hydantoins, substituted hydrazides, substituted hydrazonium salts, substituted isoxazole-pyrimidones, substituted imidazoles, substituted isothiazole-pyrimidones, substituted ketones, substituted naphthoquinones, substituted aliphatic nitriles, substituted aromatic nitriles, substituted oxadiazoles, substituted oxadiazinones, substituted oxadiazolidinediones, substituted oxadiazinediones, substituted phenols and also salts and esters thereof, substituted phosphonic acids and also salts, esters and amides thereof, substituted phosphonium chlorides, substituted phosphonalkyl-glycines, substituted phosphites, substituted phosphoric acids and also salts, esters and amides thereof, substituted piperidines, substituted pyrazoles, substituted pyrazolalkyl-carboxylic acids and also salts, esters and amides thereof, substituted pyrazolium salts, substituted pyrazolium alkyl sulphates, substituted pyridazines, substituted pyrimidines, substituted pyrrblidones, substituted pyridazones, substituted pyridine carboxylic acids and also salts, esters and amides thereof, substituted pyridines, substituted pyridine carboxylates, substituted pyridinones, substituted pyrimidones, substituted pyrrolidine carboxylic acids and also salts, esters and amides thereof, substituted pyrrolidines, substituted aryl sulphonic acids and also salts, esters and amides thereof, substituted styrenes, substituted tetrahydro-oxadiazine-diones, substituted tetrahydromethanoindenes, substituted tetrahydro-diazole-thiones, substituted tetrahydro-thiadiazine-thiones, substituted tetrahydro-thiadiazolediones, substituted thiadiazoles, substituted aromatic thiocarboxylic acid amides, substituted thiocarboxylic acids and also salts, esters and amides thereof, substituted thiolcarbamates, substituted thiophosphoric acids and also salts, esters and amides thereof, substituted triazines, substituted triazoles, substituted tetrahydro-oxadiazole-diones, substituted thioureas, substituted uracils and substituted uretidine-diones.

Furthermore, there may also be used other additives, for example non-phytotoxic additives which produce with herbicides a synergistic increase in action, for example wetting agents, emulsifiers, solvents and oily additives.

Advantageously, the active compounds of the general formula I or mixtures containing them are used in the form of herbicidal preparations, for example powders, strewable preparations, granules, solutions, emulsions or suspensions, with the addition of liquid and/or solid vehicles or diluents, and, if desired, of surface-active agents, for example wetting, adherent, emulsifying and/or dispersing assistants.

Suitable liquid carriers are, for example,. water, aliphatic hydrocarbons, aromatic hydrocarbons, for example benzene, toluene and xylene, cyclohexanone, isophorone, dimethyl sulphoxide and dimethylformamide, and also mineral oil fractions.

As solid carriers there are suitable, for example, mineral earths, for example tonsil, silica gel, talcum, kaolin, attaclay, limestone and silicic acid, and vegetable products, for example meals.

As surface-active agents there may be mentioned, for example, calcium lignin sulphonate, polyoxyethylene alkylphenyl ethers, napthalene sulphonic acids and salts thereof, phenol sulphonic acids and salts thereof, formaldehyde condensates, fatty alcohol sulphates and also substituted benzene sulphonic acids and salts thereof.

The total amount of the active substance or substances in the various herbicidal preparations may vary within wide limits. For example, the preparations may contain from 10 to 80% by weight of active compound(s), from 90 to 20% by weight of liquid or solid carrier and also, if desired, up to 20% by weight of surface-active agent(s).

The application of the active compounds' may be carried out in the usual manner, for example, with water as carrier in quantities of spray liquors from 100 to 1000 litres per hectare. It is also possible to apply the active compounds by the so-called "low volume" and "ultra-low volume" methods, and also to apply them in the form of so-called microgranules.

Among the compounds of the present invention an outstanding action is exhibited, especially, by those of the general formula I in which R represents an alkyl group containing 2 to 6 carbon atoms and B represents an alkali metal atom, preferably a lithium, sodium or potassium atom.

As alkyl groups there come into consideration, for example, ethyl, isopropyl, sec.-butyl, tert.-butyl, n-pentyl, isopentyl, neopentyl, 1-methylbutyl, 1-ethyl-propyl, n-hexyl, isohexyl and 1,1-dimethylbutyl groups.

The compounds of the present invention are salts which exist ionically corresponding to the following polar limiting formulae

or formulated in general 28

For the sake of simplicity only one of these limiting formulae is shown by the general formula I, but it is to be understood herein that each compound of the general formula I includes any one of the aforesaid ionic forms.

The hitherto unknown compounds of the general formula I may be prepared, for example, by the process of the present invention, as defined below.

The present invention accordingly further provides a process for the manufacture of a compound of the general formula I, wherein (a) dimethylcarbamoyl chloride of the formula II

is reacted in the presence of an acid-binding agent with a 1,3,4-thiadiazol-2-amine of the general formula III

in which R has the meaning given above, to form a 2-(dimethylcarbamoylimino)-1,3,4thiadiazolin-3-carboxylic acid dimethylamide derivative of the general formula IV

in which R has the meaning given above, which is then reacted with a metal compound of the general formula V B(+)Y(-) (V), in which B has the meaning given above and Y represents a hydrogen atom or a hydroxyl, Cl-C3-alkoxy or amino group, or (b) a 1-(1,3,4-thiadiazol-2-yl)-3,3-dimethyl-urea derivative of the general formula VI

in which R has the meaning given above, is reacted with a metal compound of the general formula V B(+)Y(-) (V), in which B and Y have the meanings given above.

Each step of the process of the present invention may, if desired, be carried out in the presence of a solvent.

The reaction of the components may be carried out at between 0 and 100"C, but generally at room temperature.

For the synthesis of the compounds of the present invention the reactants are preferably used in approximately equimolar quantities. As reaction media there are suitable polar organic solvents, alone or in admixture with water. Their choice depends on generally known considerations regarding the use of the metal compounds of the general formula B(+)Y(-). As solvents or suspension media there may be mentioned amongst many, for example, acid amides, for example dimethylformamide, acid nitriles, for example acetonitrile, alcohols, for example methanol or ethanol, and ethers, for example tetrahydrofuran.

For synthesizing the compounds of the general formula IV there may be used as the acid-binding agents all the usual acid-binding agents, for example organic bases, advantageously tertiary amines, for example triethylamine or N,N-dimethylaniline, pyridine derivatives, or inorganic bases, for example oxides, hydroxides, carbonates and alkanoic acid salts of alkali metal or alkaline earth metals; liquid acid-binding agents may serve simultaneously as solvents.

The isolation of the compounds of the present invention formed is carried out finally by distilling off the solvent used under atmospheric or a reduced pressure or by precipitation with weakly polar organic solvents, for example with ketones, for example acetone, or ethers, for example diisopropyl ether.

The compounds of the present invention are colourless and odourless crystalline solids, which are excellently soluble in water, readily soluble in polar organic solvents, for example carboxylic acid amides, for example dimethylformamide, sulphoxides, for example dimethyl sulphoxide, and lower alcohols, for example methanol and ethanol, sparingly soluble in carbonitriles, for example acetonitrile, and insoluble in hydrocarbons, halogenated hydrocarbons, ethers and ketones.

The following Examples illustrate the invention. Examples 1 and 2 illustrate the manufacture of compounds of the general formula I and Examples 3 to 5 illustrate the mode of action of the compounds of the general formula I.

Example 1 27.1 Grams of 5-ethyl-2-(dimethylcarbamoylimino)-1 ,3 ,4-thiadiazolin-3-carboxylic acid dimethylamide melting at 100 C were suspended in 150 ml of methanol. There was added dropwise, while stirring, a solution of 4 grams of sodium hydroxide in 100 ml of methanol at room temperature. After 3 hours there was obtained a clear solution, from which the methanol was then distilled off in vacuo. The residue that remained was digested with acetonitrile, filtered with suction to remove the washing agent and dried in vacuo at 80"C.

Yield: 15.5 grams (69.8% of the theoretical yield) of the sodium salt of 5-ethyl-2 (dimethylcarbamoylimino)-l ,3,4-thiadiazolin-3-ide having a melting point of > 250 C.

H11N4NaOS M.W.: 222.26 Analysis Calculated: C 37.83% H 4.99% N 25.21% Na 10.34% Found: C 37.70% H 5.05% N 24.95% Na 10.76%.

Example 2 8.1 Grams of 1-(5-tert.-butyl-1,3,4-thiadiazol-2-yl)-3,3-dimethyl-urea melting at 1210C were dissolved together with 0.853 gram of lithium hydroxide in 70 ml of methanol. The solution was then concentrated in vacuo, and the residue was triturated with a mixture of diisopropyl ether and isopropanol, filtered off with suction and washed with diethyl ether.

By drying in vacuo at 1200C there were obtained 7.8 grams (93.8% of the theoretical yield) of the lithium salt of 5-tert.-butyl-2-(dimethylcarbamoylimino)-1,3-4-thiadiazolin-3-ide having a melting point of > 250 C.

C9H,5LiN4OS M.W.: 234.26 Analysis Calculated: C 46.15% H 6.45% N 23.92% Li 2.96% Found: C 46.04% H 6.33% N 23.73% Li 2.68%.

Each of the other compounds of the present invention listed in the following Table may be prepared in a manner analogous to that described in Example 1 or 2.

Name of the compound Physical constant Sodium salt of 2-(dimethylcarbamoylimino)- M.p.: 288"C 5-isopropyl- 1,3,4-thiadiazolin-3-ide (with decomposition) Sodium salt of 5-tert.-butyl-2-(dimethyl- M.p.: 306"C carbamoylimino)-1,3,4-thiadiazolin-3-ide (with decomposition) Potassium salt of 5-ethyl-2-(dimethyl- M.p.: > 250 C carbamoylimino)- 1,3 ,4-thiadiazolin-3-ide Lithium salt of 5-ethyl-2-(dimethyl- M.p.: > 250 C carbamoylimino)-1,3,4-thiadiazolin-3-ide Lithium salt of 2-(dimethylcarbamoylimino)- M.p.: > 250 C 5-isopropyl-1,3,4-thiadiazolin-3-ide Lithium salt of 5-(1,1-dimethylbutyl)-2- M.p.: > 250 C (dimethylcarbamoylimino)- 1,3 ,4-thiadiazolin- 3-ide Compound of the present Pre-emergence Post-emergence invention Sinapis Solanum Sinapis Solanum Sodium salt of 2-(dimethylcarbamoylimino)-5isopropyl-1,3,4-thiadiazolin-3-ide 4 4 4 4 Sodium salt of 5-tert.-butyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide 4 4 4 4 Sodium salt of 5-ethyl-2-(dimethylcarbamoylimino)1,3,4-thiadiazolin-3-ide 4 4 4 4 Potassium salt of 5-ethyl-2-(dimethylcarbamoylimino)1,3,4-thiadiazolin-3-ide 4 4 4 4 Lithium salt of 5-ethyl-2-(dimethylcarbamoylimino)1,3,4-thiadiazolin-3-ide 4 4 4 4 Lithium salt of 2-(dimethylcarbamoylimino)-5-isopropyl1,3,4-thiadiazolin-3-ide 4 4 4 4 Lithium salt of 5-tert.-butyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide 4 4 4 4 Lithium salt of 5-(1,1,-dimethylbutyl)-2 (dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide 4 4 4 4 0 = no action 10 = destruction of the plant Example 3 In a series of tests carried out in a greenhouse the compounds of the present invention mentioned in the Table below were each sprayed at a rate of application of 5 kg of active substance per hectare, dissolved in 500 litres of water per hectare, on to Sinapis sp. and Solanum sp. as test plants by the pre- and post-emergence methods. Three weeks after the treatment the results thereof were evaluated, the results being expressed by a numerical scale extending from 0 to 4, the value 0 representing no action and the value 4 representing destruction of the plant. As will be seen from the Table destruction of the test plants was generally achieved.

Example 4 In a series of tests carried out in a greenhouse the plants mentioned in the following Table were treated before their emergence with the listed agents being tested at a rate of application of 1 kg of active substance per hectare. For this purpose the agents were in each case applied uniformly to the soil in the form of an aqueous solution using 500 litres of water per hectare. The results show that the compounds of the present invention have a better action than the known compound used for comparison. The results are expressed by a numerical scale extending from 0 to 10, the value 0 representing destruction of the plant and the value 10 representing no damage.

? 27?i2n9S o c9 1 1 d 27suw0dI o ':i II 0 s uinuisll2N275Si219 o o Compound of the present invention I m Sodium salt of Sn21]Ut1113UI o o 10 10 o 8 o 0 0 0 0 0 0 '3 tlaAnMua3 o o m C\1 I \0 '21 Ui72?Ui277 O 5-tert.-butyl-2-(dimethyl- O O 8 0 0 0 O C\1 carbamoylimino)-1 ,3,4-thiadiazolin-3-ide '2lD salt of 27?il79?il27W o o 10 10 8 9 o 0 0 0 0 0 moylimino)- 1,3 ,4-thiadiazolin-3-ide Potassium salt of 5-ethyl-2-(dimethyl- 1 10 10 9 10 - O 0 0 0 0 0 'Ui 27?i27ll92S s s ,3 s s m untfSIos salt of 5-ethyl-2-(dimethylcarba- I I 10 10 I 7 4 H moylimino)-1 ,3,4-thiadiazolin-3-ide o agent (according to I I I \o az;rell\I I EI No. S: ea6 1 1 10 10 9 10 6 10 5 0 0 2 6 0 4 0 0 6 urea - not tested lel d of the plant nu-punolD o o o o uesq w{sng I I I I I ~ oDuelsqns sA!}oe Jo ex ~ ~ H H ~ ~ o Erv E = > > =9n s = Sn9 0 c , < c n1 bt4 eD c., ~ os c ~ ~ A c z .Y w0 N Y v z | ; 9 e9 c: 52 S ~ > n Q < 5 't V N = m ,v < , , < C s rv O: e4 c E W E i E E i S t XI t v E v U ~1 E Z ~ = ~ Example 5 In a series of tests carried out in a greenhouse the plants mentioned in the following Table were treated after their emergence with the listed agents being tested at a rate of application of 1 kg of active substance per hectare. For this purpose the agents were in each case sprayed uniformly over the plants in the form of an aqueous solution using 500 litres of water per hectare. Also in this case, three weeks after the treatment, the compounds of the present invention exhibited a high selectivity coupled with an excellent action against the weeds. The agent used for comparison did not exhibit a good action. Again, the results are expressed by a numerical scale extending from 0 to 10, the value 0 representing destruction of the plant and the value 10 representing no damage.

? 27?i2729S n n m o o Ho d oazuod o o o o o .,' s uxnuis2/2u27sKi2lD '27 NS C :z C C Compound of the o invention o o o oo Sodium salt of 279in272u99 o o | 1 o o o 0 0 0 0 0 0 oo 5-isopropyl-l ,3,4-thiadiazolin-3-ide Sodium salt of 5-tert.-butyl-2-(dimethyl- o o 8 o O 0 c9 carbamoylimino)-l ,3,4-thiadiazolin-3-ide 2/D salt of 27?i27:)?i227211 O o 10 N 10 10 m O O O 1 - 0 0 oo carbamoylimino)- 13 ,4-thiadi'izolin-3-ide Potassium salt of 5-ethyl-2-(dimethylcarba- 1 - 10 - 9 8 o o o o o o o e 0000000 27?227ll92S o o o o o o o ~ Lithium salt of 5-ethyl-2-(dimethyl- 1 I 10 7 9 10 10 8 1 0 0 0 - 0 3 0 1 3 carbamoylimino)- I 3 ,4-thiadiazolin-3-ide a3!I salt of 2-(dimethylcarbamoy- l - 8 - - - - ~ l l ~ limino)-5-isopropyl-l ,3,4-thiadiazolin-3-ide JZ!8N salt of 5-tert.-butyl-2-(dimethyl- I I - oo oo ~ I I H ead I I Ho on ay I I H Companson agent (according to German Offenlegungsschrift No. I Inu-punolf) oo 10 H0 10 10 10 10 1 4 8 2 8 8 10 1 5 10 ueaq ysn I I r I I I I m - = not tested 0 = destruction of the plant 10 = no damage JAIlDe Ao ex l l o , s r ,, En ev c : c c c '~ cv c E c c < 'V D . s~ O , O C ' rV D J O + - t~ C D C > Ct C ,'5 4 C .. D 5 > -s C csz t D 56 - 9 C5 f t CS Wt Ct 9 rS r CS V o) C r~ m C '~&commat; r~ V r < ) s~ C CS O 'c Wo ;0' < . Wo c o = - < 90 o s m O oc=: ~ w E ; E ,x, E E X ~ m E E E En E E U s cr , O =s D r D L C - D ~1 , Q Z T v I o o

Claims

WHAT WE CLAIM IS: 1. A 2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide salt of the general formula I

in which R represents an aliphatic hydrocarbon group containing at least 2 carbon atoms, with the proviso that when R represents an alkyl group containing less than 5 carbon atoms, a methyl group is directly attached to the 1-position of the alkyl group, and B represents a monovalent metal equivalent.
2. A compound as claimed in claim 1, wherein R represents an alkyl group containing 2 to 6 carbon atoms.
3. A compound as claimed in claim 1 or 2, wherein B represents an alkali metal atom.
4. A compound as claimed in claim 3, wherein the alkali metal atom is a lithium, sodium or potassium atone.
5. Sodium salt of 5-ethyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide.
6. Lithium salt of 5-tert.-butyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide.
7. Sodium salt of 2-(dimethylcarbamoylimino)-5-isopropyl-1,3,4-thiadiazolin-3-ide.
8. Sodium salt of 5-tert.-butyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide.
9. Potassium salt of 5-ethyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide.
10. Lithium salt of 5-ethyl-2-(dimethylcarbamoylimino)-1,3,4-thiadiazolin-3-ide.
11. Lithium salt of 2-(dimethylcarbamoylimino)-5-isopropyl-1,3,4-thiadiazolin-3-ide.
12. Lithium salt of 5-(1,1-dimethylbutyl)-2-(dimethylcarbamoylimino)-1,3,4thiadiazolin-3-ide.
13. A process for the manufacture of a compound as claimed in claim 1, wherein (a) dimethylcarbamoyl chloride of the formula II

is reacted in the present of an acid-binding agent with a 1,3,4-thiadiazol-2-amine of the general formula 111

in which R has the meaning given in claim l to form a 2-(dimethylcarbamoylimino)-1,3,4 thindiazolin-3-carhoxylic acid dimethylamide derivative of the general formula IV

in which R has the meaning given above. which is then reacted with a metal compound of the general formula V B(q- )Y( - ) (V) in which B has the meaning given in claim I and Y represens a hydrogen atom or a hydroxy C-C-alkoxy or amino group. or (b) a 1-(1,3,4-thiadiazol-2-yl)-3,3-dimethyl-urea derivative of the general formula VI

in which R has the meaning given above, is reacted with a metal compound of the general formula V B(+)Y(-) (V), in which B and Y have the meanings given above.
14. A process-as claimed in claim 13, wherein each step is carried out in the presence of a solvent.
15. A process as claimed in claim 13, conducted substantially as described herein.
16. A process for the manufacture of a compound as claimed in claim 1, conducted substantially as described in Example 1 or 2 herein.
17. A herbicidal preparation which comprises a compound as claimed in claim 1, in admixture or conjunction with a suitable carrier.
18. A herbicidal preparation which comprises a compound as claimed in any one of claims 2 to 4, in admixture or conjunction with a suitable carrier.
19. A herbicidal preparation which comprises the compound claimed in any one of claims 5 to 12, in admixture or conjunction with a suitable carrier.
20. A preparation as claimed in any one of claims 17 to 19, which is in the form of a powder, a strewable preparation, granules, a solution, an emulsion or a suspension.
21. A preparation as claimed in any one of claims 17 to 20, containing a single compound of the general formula I in an amount of from 10 to 80% by weight.
22. A preparation as claimed in. any one of claims 17 to 20, containing two or more compounds of the general formula I in a total amount of from 10 to 80% by weight.
23. A preparation as claimed in any one of claims 17 to 22, containing a single surface-active agent in an amount of up to 20% by weight.
24. A preparation as claimed in any one of claims 17 to 22, containing two or more surface-active agents in a total amount of up to 20% by weight.
25. A herbicidal preparation as claimed in claim 17 and substantially as described in Example 3 herein.
26. A herbicidal preparation as claimed in claim 17 and substantially as described in Examples 4 and 5 herein.
27. A method of protecting a living plant against weeds, wherein the area in the vicinity of a living plant is treated with a compound as claimed in claim 1.
28. A method as claimed in claim 27, wherein the area is treated with a compound as claimed in any one of claims 2 to 4.
29. A method as claimed in claim 27, wherein the area is treated with the compound claimed in any one of claims 5 to 12.
30. A method as claimed in claim 27, wherein the area is treated with a herbicidal preparation as claimed in any one of claims 17 to 26.
31. A method as claimed in any one of claims 27 to 30, wherein a single compound of the general formula I is used for the treatment in an amount within the range of from 0.5 to 5 kg per hectare.
32. A method as claimed in any one of claims 27 to 30, wherein two or more compounds of the general formula I are used for the treatment in a total amount within the range of from 0.5 to 5 kg per hectare.
33. A method as claimed in claim 27, conducted substantially as described in Example 4 or 5 herein.
34. A method of protecting a crop area against weeds, wherein a crop area is treated with a compound as claimed in claim 1.
35. A method as claimed in claim 34, wherein the crop area is treated with a compound as claimed in any one of claims 2 to 4.
36. A method as claimed in claim 34, wherein the crop area is treated with the compound claimed in any one of claims 5 to 12.
37. A method as claimed in claim 34, wherein the crop area is treated with a herbicidal preparation as claimeci in any one of claims 17 to 26.
38. A method as claimed in any one of claims 34 to 37, wherein a single compound of the general formula I is used for the treatment in an amount within the range of from 0.5 to 5 kg per hectare.
39. A method as claimed in any one of claims 34 to 37, wherein two or more compounds of the general formula I are used for the treatment in a total amount within the range of from 0.5 to 5 kg per hectare.
40. A method as claimed in any one of claims 34 to 39, wherein the crop is a bush bean, ground-nut, potato, pea, maize, rice, sorghum or soya crop.
41. A method of protecting waste land against weeds, wherein the waste land is treated with one or more compounds as claimed in claim 1, the compound(s) being used in a total amount of more than 5 kg per hectare.
42. A pack which comprises a compound as claimed in claim 1, together with instructions for its use as a herbicide.
43. A pack which comprises a compound as claimed in any one of claims 2 to 4 together with instructions for its use as a herbicide.
44. A pack which comprises the compound claimed in any one of claims 5 to 12 together with instructions for its use as a herbicide.

Reference has been directed in pursuance of Section 9, subsection (1) of the Patents Act 1949, to patent No. 1266992.