KR810001152B1 - Process for preparing 1,2,3-thiadiazole-5-carboxylic acid derivatives - Google Patents

Abstract

Title compds. (I; R1 = H, alkyl; X = -Y-R2; R2 = H, aryl, alkyl; Y = O, S), useful as herbicides and plant growth regulators, were prepd. by the reaction of II and III, or V and IV(R3 and R4 are H, C1-18 alkyl, C2-8 alkenyl, C3-8 aliphatic hydrocarbon, aryl). Thus, 33.4 g 4-methyl-1,2,3-thiadiazole-5,-5-carboxylic ethylester and sodium chloride were reacted in 3N-methanol at room temp for 16 hr to give 25.9 g 4-methyl-1,2,3-thiadiazole-5-carboxylic acid.

Description

Method for preparing 1,2,3-thiadiazole-5-carboxylic acid derivative

The present invention relates to a process for the preparation of 1,2,3-thiadiazole-5-carboxylic acid derivatives of the following structural formula (I) effective as herbicides and plant growth regulators.

의 그룹으로서 여기서 R₃및 R₄는 각각 수소, 비치환 또는 치환된 C₁-C₁₈-알킬그룹, C₂-C₈-알케닐 또는-알키닐그룹, 비치환 또는 치환된 C₃-C₈-지환족 탄화수소그룹 또는 비치환 또는 치환된 아릴그룹, 또는 R₃및 R₄가 인접한 질소와 함께 모르폴리노, 피페리디노 또는 피롤리디노그룹을 나타낸다.In the above formula, R ₁ represents a hydrogen atom or an alkyl which may be inserted at least one of oxygen or sulfur atoms and may be substituted with at least one halogen, X is a group of the formula -YR ₂ wherein R ₂ is hydrogen, non- Ring or substituted alkyl group, unsubstituted or substituted aryl group, unsubstituted or substituted aryl-C ₁ -C ₂ -alkyl group, or monovalent metal equivalent, Y represents oxygen or sulfur, or X Is a structural formula

Wherein R ₃ and R ₄ are each hydrogen, unsubstituted or substituted C ₁ -C ₁₈ -alkyl group, C ₂ -C ₈ -alkenyl or -alkynyl group, unsubstituted or substituted C ₃ -C _{An 8} -alicyclic hydrocarbon group or an unsubstituted or substituted aryl group, or R ₃ and R ₄ together with the adjacent nitrogen represent a morpholino, piperidino or pyrrolidino group.

There are three essential functions to remove weeds when planting. Crops should be safe, harvested crops useful, working conditions and yields improved. Modern weed removal first suggests new soil cultivation methods, such as those required for the cultivation of cereals, maize or chard, or direct sowing used in maize, grains, soybeans and cotton.

Conventional herbicides have not met the conditions for the development of tillage and horticultural economy, and therefore, there is a need for improvements in weed removal techniques.

The problem on which the present invention is based is to provide an improved weed removal reagent.

This problem can be solved by the compound of formula (I) of the present invention.

"Aryl group" includes heterocyclic groups having aromatic properties here.

R ₃ and R ₄ have the same or different meanings.

An unsubstituted or substituted alkyl group which may mean R ₃ and R ₄ is an unsubstituted or substituted aryl-C ₁ -C ₃ -alkyl group or an unsubstituted or substituted C ₃ -C ₈ -cycloalkyl-C ₁ Or a -C ₃ -alkyl group. Unsubstituted or substituted aryl groups which may mean R ₃ and R ₄ are substituted with one or more groups selected from alkyl, halogen, alkoxy, nitro group and trifluoromethyl group having 1 to 6 carbon atoms It may be an aromatic hydrocarbon.

The compounds of the present invention may be classified into soil treated herbicidal and / or foliar herbicidal action against annual weeds and perennial weeds. This action is partially permeable.

Examples of weeds in which herbicidal action is particularly advantageous are Digigitalis, Trifolium, Portulaca, Papaver, Daucus, Kochia, Zipophila Gypsophyla, Lactuca, Solanum, Fscholtzia, Cheiranthus, Phacelia, Euphorbia, Linum, Convolvulus ), Brassica, Datura, Chicorium, Ipomoea, Setaria, Agrostis, Phleum, Allopecurus ), Phalaris, Dactylis, Festuca, Arhenaterum, Lolium, Bromus, Avena, Allium , Cucumis, Medicago, Stellaria, Sentellio, Matricaria, Lamium, Centaurea, Amarantus, Gallium, Chrysanththemum, Polygonum, Sorghum, Alopecurus, Echinochloa, Digitaria, Incense Dicotyledonous and monocotyledonous in the genus Cyperus and Poa.

Herbicide application rates range from about 0.5 to 5 kg of active substance per hectare. Even when two or more compounds of the formula (I) are used, the total amount used is in the range of about 0.5 to 5 kg.

Selective weeding is also possible, such as cereals, cotton, beans and agricultural crops. These actives are most effective when sprayed when weeds grow or before germination.

The annual crop may be sown a few days after the active material is applied.

Each compound of the present invention may alter the development of a plant's condition in order to obtain various properties that are agriculturally and horticulturally useful.

The compounds of the present invention can be used in seeds, seedlings before and after germination, or in roots, stems, leaves, flowers, fruits or other parts of plants.

In general, the regulation of natural growth can be seen by looking at the size, shape, color or structure of the part of the treated plant.

Visually evident morphological changes always include physiological and biochemical changes of the plant. Numerous analytical methods have been attempted to elucidate this property and biochemical and physiological changes. For example, the following changes in plant development caused by the compounds of the present invention may be mentioned:

Suppress vertical growth

Inhibition of Root Development

Stimulates the lateral growth of shoots from the developing or lower eye.

To strengthen the formation of plant pigments.

Defoliation.

The compounds of the present invention satisfy all the necessary functions for improving the weed removal techniques which have not been known so far.

The present invention also provides the preparation of herbicides as a mixture of the compounds of formula (I) or together with a suitable carrier.

As noted above, this preparation not only has herbicidal action but also acts as a plant growth regulator. This preparation, of course, comprises at least one compound of the formula (I).

The present invention also provides a method of protecting a plant from weeds and / or a method of controlling growth of a plant treated with the compound of formula (I).

Furthermore, the present invention provides a method of protecting the soil from weeds and / or allowing plants to grow in soil treated with the compound of formula (I). This soil can cultivate grain, wheat, corn, rice, cotton, soybeans or agricultural crops.

The invention also provides a Pack comprising a compound of formula (I), depending on the use as a herbicide and / or as a plant growth regulator.

Among the compounds of the invention are in particular the compounds of formula (I) having herbicidal and plant growth control properties as described above, wherein R ₁ is hydrogen or unsubstituted or chlorine or bromine-substituted alkyl groups having 1 to 4 carbon atoms, eg For example methyl, propyl, chloromethyl or bromomethyl group, R ₂ is hydrogen, alkyl group of 1 to 4 carbon atoms, for example methyl, ethyl, propyl, isopropyl or butyl group, unsubstituted or substituted aromatic Hydrocarbon groups, for example phenyl or chlorophenyl, nitrophenyl or methylphenyl groups, for example 4-chlorophenyl, 4-nitrophenyl, 3-chlorophenyl, 2-chlorophenyl or 4-methylphenyl group, alkali metal elements, preferably The following represent one equivalent of a lithium, sodium or potassium atom or a divalent metal such as zinc, manganese, calcium, magnesium or barium, and Y represents an oxygen or sulfur atom and R ₃ and R ₄ Are hydrogen, unsubstituted or halogen, phenoxy-, dialkylamino-, alkoxy- or alkoxycarbonyl-substituted C ₁ -C ₈ -alkyl groups, C ₂ -C ₆ -alkenyl or -alkynyl groups, Unsubstituted or substituted C ₃ -C ₈ -cycloalkylmethyl group, unsubstituted or substituted C ₆ -C ₈ -cycloalkyl group or phenyl, chlorophenyl, nitrophenyl or methylphenyl group. R ₃ and R ₄ are the same or different groups selected from the following preferred groups.

The meanings of R ₃ and R ₄ are as follows.

For example, hydrogen, unsubstituted C ₁ -C ₁₈ -alkyl groups include methyl, ethyl, propyl, isopropyl, n -butyl, tertbutyl, 2,2-dimethyl-1-propyl, n -heptyl, n - nonim, n-undecyl, n-octadecyl, 3-methylbutyl, 4-methyl-2-pentyl, isobutyl, 3,3-dimethyl-butyl, 2-butyl or 3,3-dimethyl-2-butyl, Substituted C ₁ -C ₁₈ -alkyl groups include 2-chloroethyl, 3-chloropropyl, 3-bromopropyl, 2-bromomethyl, 1-phenoxy-2-propyl, 3-dimethylaminopropyl, 2 -Dimethylaminoethyl, 3-diethylaminopropyl, tetrahydrofurfuryl, ethoxycarbonylmethyl, cyanomethyl, 2,2-dimethoxyethyl or 2-ethoxyethyl, unsubstituted and substituted C ₃ -C ₈ -cycloalkyl-C ₁ -C ₃ -alkyl groups include cyclohexylmethyl, 4-cyanocyclohexylmethyl, 4-hydroxymethylcyclohexylmethyl, 4-carbonylcyclohexylmethyl, cycloheptylmethyl, cyclooctyl Methyl or cycloprop Phil methyl, C ₂ -C ₈ -alkenyl or -alkynyl groups include 2-propenyl, 2-butenyl, 2-methyl-2-propenyl, 2-propynyl or 3-ethyl-1-pentyl- 3-yl, unsubstituted or substituted aryl-C ₁ -C ₃ -alkyl groups include benzyl, 4-chlorobenzyl, 3-chlorobenzyl, 2-chlorobenzyl, 4-fluorobenzyl, 3-fluorobenzyl, 2-fluorobenzyl, 4-methylbenzyl, 3-methylbenzyl, 2-methylbenzyl, 3,4-methylenedioxybenzyl, 2,4-dichlorobenzyl, 3,4-dichlorobenzyl, 4-methoxybenzyl, 3-methoxybenzyl, 2-methoxybenzyl, 2-pyridylmethyl, 3-pyridylmethyl, 4-pyridylmethyl, α, α-dimethylbenzyl, 1-phenylethyl, 2-phenylethyl, 1,2 -Diphenylethyl, 2,2-diphenylethyl, 4-fluoro-α-methylbenzyl, 3-phenylpropyl or 2-furfuryl, unsubstituted or substituted -cyclo aliphatic hydrocarbon groups include cyclopropyl, cyclo Pentyl, cyclohexyl, 2-methylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohex , 1-ethynylcyclohexyl, cycloheptyl or cyclooctyl and unsubstituted or substituted aromatic hydrocarbon groups include phenyl, 3-chlorophenyl, 2-chlorophenyl, 4-chlorophenyl, 2,4-dichlorophenyl, 4- Fluoro phenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 1-naphthyl, 2-methoxyphenyl, 3-methoxyphenyl or 4-nitrophenyl.

The compound of the present invention may be used alone or in the form of a mixture with another compound of the present invention or with another active compound.

According to the desired purpose, a substance having the following herbicidal activity may be added to the compound of the present invention.

Substituted aniline,

Substituted aryloxycarboxylic acids and their salts, esters and amides,

Substituted ethers,

Substituted arson acids and their salts, esters and amides,

Substituted benzimidazoles,

Substituted benz isothiazole,

Substituted benz thiadiazinone dioxide,

Substituted benz oxazines,

Substituted benz oxazinones,

Substituted benzthiazoles,

Substituted benz thiadiazoles,

Substituted Burettes

Substituted quinoline,

Substituted carbamate,

Substituted aromatic carboxylic acids and their salts, esters and amides,

Substituted aromatic carboxylic acids and their salts, esters and amides,

Substituted carbamoyl alkyl thio- or dithio-phosphates ,.

Substituted quinazolines,

Substituted cycloalkylamido carbothiolic acids and their salts, esters and amides,

Substituted cycloalkyl carbonamido-thiazoles,

Substituted dicarboxylic acids and their salts, esters and amides,

Substituted dihydrobenzofuranyl sulfonates,

Substituted disulfide,

Substituted dipyridyl salts,

Substituted dithio carbamate,

Substituted dithiophosphoric acid and salts, esters and amides thereof,

Substituted urea,

Substituted hexahydro-1H-carbothioate,

Substituted highdanro,

Substituted hydrazide,

Substituted hydrazonium salts,

Substituted isooxazole pyrimidines,

Substituted imidazole,

Substituted isothiazolpyrimidone,

Substituted ketones,

Substituted naphthoquinones,

Substituted aliphatic nitriles,

Substituted aromatic nitriles,

Substituted oxadiazoles,

Substituted oxadiazinone,

Substituted oxadiazolidinediones,

Substituted oxadiazinedione,

Substituted phenols and their salts and esters,

Substituted phosphonic acids and their salts, esters and amides,

Substituted phosphonium chloride,

Substituted phosphonalkylglycines,

Substituted phosphites,

Substituted phosphoric acid and salts, esters and amides thereof,

Substituted piperidine,

Substituted pyrazoles,

Substituted pyrazole alkylcarboxylic acids and their salts, esters and amides,

Substituted pyrazolium salts,

Substituted pyrazolium alkyl sulfates,

Substituted pyridazines,

Substituted pyridazoles,

Substituted pyridine carboxylic acids and their salts, esters and amides,

Substituted pyridine,

Substituted pyridine, carboxylate,

Substituted pyridinones,

Substituted pyrimidone,

Substituted pyrrolidines, carboxylic acids and their salts, esters and amides,

Substituted pyrrolidines,

Substituted pyrrolidinone,

Substituted aryl sulfonic acids and salts, esters and amides thereof,

Substituted styrene,

Substituted tetrahydro oxadiazinedione,

Substituted tetrahydro metanoindenes,

Substituted tetrahydro-diazole-thione,

Substituted tetrahydro-thiadiazine-thione,

Substituted tetrahydro-thiadiazoledione,

Substituted aromatic thiocarboxylic acid amides,

Substituted thio carboxylic acids and their salts, esters and amides,

Substituted thio carbamates,

Substituted thiourea,

Substituted thiophosphoric acid and salts, esters and amides thereof,

Substituted triazines,

Substituted triazoles,

Substituted uracil,

Substituted uretidinedione,

Oxin,

α- (2-chlorophenoxy) -propionic acid,

4-chlorophenoxy acetic acid,

2,4-dichlorophenoxy acetic acid,

Indolyl-3-acetic acid,

Indolyl-3-butyric acid,

α-naphthyl acetic acid,

-나프톡시아세트산,

Naphthoxyacetic acid,

Naphthylacetamide,

N- m -tolylphthalamic acid,

Gibberellin,

S, S, S-tri- n -butyl-trithiophosphoric acid ester,

Cytokine,

2-chloro ethylphosphoric acid,

2-chloro-9-hydroxyfluorene-9-carboxylic acid,

2-chloroethyl-trimethylammonium chloride,

N, N-dimethylaminosuccinic acid amide,

2-isopropyl-4-trimethylammonio-5-methylphenylferridine-1-carboxylic acid ester chloride,

Phenyl isopropyl-carbamate,

3-chloro phenyl isopropyl-carbamate,

Ethyl 2- (3-chlorophenylcarbamoyloxy) -propionate,

Male Hydrazide,

2,3-dichloroisobutyric acid,

Di- (methoxythio carbonyl) disulfide,

1,1'-dimethyl-4,4'-bipyridyldium dichloride,

3,6-endooxohexahydrophthalic acid,

3-amino-1,2,4-triazole,

1,2,3-thiadiazolyl-5-yl-urea derivative,

1- (2-pyridyl) -3- (1,2,3-thiadiazol-5-yl) urea,

2-butylthio-benzthiazole,

2- (2-methylpropylthio) -benzthiazole,

3,4-dichloroisothiazole-5-carboxylic acid,

2,3-dihydro-5,6-dimethyl-1,4-dithiin-1,1,4,4-tetraoxide,

arsenic acid,

Cacodil Acid,

Chlorates, preferably calcium chlorate, potassium chlorate,

Magnesium chlorate or sodium chlorate,

Calcium cyanamide,

Potassium iodide,

Magnesium chloride,

Mount Apsis,

Nonanol,

N- (phosphonomethyl) -glycine monoisopropylamine salt and N, N-bis- (phosphonomethyl) -glycine.

Other additives may also be used, for example additives that are not phytotoxic, such as wetting agents, emulsifiers, solvents and oily additives which increase synergism when used with herbicides.

Advantageously the active compounds or mixtures comprising the compounds of the invention are in the form of preparations, such as bonsai, sprays, granules, solutions, emulsions or suspensions, liquid and / or solid carriers or diluents and, if desired, surfactants, for example Surfactants, such as a hydrating agent, an adhesive, an emulsifier, and / or a dispersing agent, are added and used.

Suitable liquid carriers are, for example, water, aliphatic and aromatic hydrocarbons, cyclohexane, isophorone, dimethylsulfoxide, dimethyl formamide, and mineral oils.

Suitable solid carriers include mineral products, tonsils, silica gel, talc, kaolin, atacler, limestone, silicic acid and grain products.

Surfactants that can be used include calcium ligninsulfonate, polyoxyethylene alkylphenyl ethers, naphthalene sulfonic acids and their salts, phenol sulfonic acids and their salts, condensates of formaldehyde, fatty alcohol sulfates and also substituted benzenesulfonic acids and There are their salts.

The proportions of the active ingredients and various preparations can vary widely. For example, the formulation may include from about 10 to 80 weight percent of the active ingredient, from about 90 to 20 weight percent of the liquid and solid carrier, if desired, of 20 weight percent of the surfactant.

The active compounds of the present invention can be used in a conventional manner, for example, by spraying 100 to 1000 liters per hectare into a large amount of spray liquid using water as a carrier. It may also be used in the form of a microdispersion method and an ultramicrodispersion method or fine particles.

The novel compounds of the invention can be prepared, for example, by the process of the invention described below.

The present invention also provides a process for producing the compound of formula (I).

(A) 1,2,3-thiadiazole-5-carboxylic acid halide of the compound of formula (III)

Wherein R ₁ has the meaning given above and Z is a halogen, preferably a chlorine atom, a phosphorus compound, reacted with a compound of formula IV in the presence of an acid binder.

H -X (Ⅳ)

X has the meaning given above.

(B) On the other hand, when X is a compound (I) having the following structural formula

As 1,2,3-thiadiazole-5-carboxylic acid ester of the compound of formula (V)

In the above, R ₁ , R ₂ and Y react the compound having the above meaning with the amine of the following structural formula.

In the above structural formula, R ₃ and R ₄ have the above meaning.

The reaction of the reaction components takes place between 0 ° and 120 ° C. and generally occurs at room temperature to the reflux temperature of the characteristic reaction mixture.

Almost equimolar amounts of reactants are used in the synthesis of the compounds of the invention. Suitable reaction media are reactants and inert solvents. Examples include halogenated hydrocarbons and petroleum ethers such as methylene chloride, chloroform and carbon tetrachloride, aliphatic and aromatic hydrocarbons such as cyclohexane, benzene, toluene and xylene, alcohols such as methanol and ethanol, acetone, methyl isobutyl ketone and iso Ketones such as poron and ethers such as diethyl ether, tetrahydrofuran and dioxane, and carboxylic acid nitriles such as acetonitrile.

Acid binders include organic bases such as triethyl amine, N, N-dimethylaniline and pyridine bases and oxides, hydroxides and carbonates of alkaline earth metals and alkali metals.

Liquid bases of pyridine can also be used as solvents.

Compounds of the invention prepared by the process of the invention can be separated from the reaction mixture by conventional methods, for example by distillation of the solvent under normal or reduced pressure, precipitation with water or fractional distillation.

The unique compounds of the present invention are listed in the following table.

TABLE 1

The compound of the present invention is a colorless, odorless crystalline solid or colorless odorless liquid, poorly soluble in water, soluble in aliphatic hydrocarbons such as petroleum ether and cyclohexane, and aromatics such as halogenated hydrocarbons such as chloroform and carbon tetrachloride, benzene, toluene and xylene Ethers such as hydrocarbons, diethyl ether, tetrahydrofuran and dioxane, ketones such as acetonitrile, carboxylic acid natril, acetone, alcohols such as methanol and ethanol, carboxylic acid amides such as dimethylformamide, and sulfoxides such as dimethyl sulfoxide Melts well on back

Cyclohexane, acetonitrile and alcohols are particularly suitable as recrystallization solvents.

1,2,3-thiadiazole-5-carboxylic acids and their metal salts are readily soluble in water and poorly soluble in organic solvents.

Starting materials for the production of the compounds of the invention can be known or prepared by known methods.

The following examples illustrate the invention. Examples 1 to 3 relate to the production of the compounds of the invention and Examples 4 to 8 illustrate the advantages in the application of the compounds of the invention.

Example 1

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (Compound No. 2)

To 33.4 g (0.194 water) of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid ethyl ester is added 3N-methanol solution of sodium hydroxide and the mixture is left at room temperature for 16 hours. Methanol is distilled off in vacuo and the remaining sodium salt is washed with ether. This salt is dissolved in 200 ml of water and acidified with dilute hydrochloric acid. The product is filtered and washed with pentane. Recrystallize from ethyl acetate / hexanes.

Yield: 25.9 g = 96% yield of theory

Melting point: colorless crystals of 174 to 175 ℃

Example 2

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (4-fluorobenzylamide) (Compound No. 3)

9.4 g (0.075 water) of 4-fluorobenzylamine is dissolved in 100 ml of tetrahydrobutane and 10.4 ml (0.075 water) of triethylamine are added at room temperature. Stir and cool and add 12.2 g of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid chloride having a boiling point of 48 to 50 ° C / 0.5 Torr dropwise at 10 ° C. The mixture is stirred for 4 hours. The precipitate is suction filtered and the filtrate is concentrated and treated with ether. The product is recrystallized from ethanol.

Yield: 14.2 g = 75.5% of theory

Melting point: colorless crystals at 106 to 107 ° C

Example 3

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (cyclohexylmethylamide) (Compound No. 4)

Dissolve 17.2 g (0.1 mole) of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid ether ester in 30 ml of anhydrous ethanol, add 11.3 g (0.1 mole) of aminomethylcyclohexane at room temperature, and add this mixture. Heat to reflux for 3 hours. The solution is concentrated and the remaining oil is treated with isopropyl ether. The product is recrystallized from cyclohexane.

Yield: 22.9 g = 96% of theory

Melting point: colorless crystals of 79 to 80 ℃

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid chloride as a starting material for preparing compound 3

103.6 g (0.72 mol) of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid are added to 280 ml of thionyl chloride.

The mixture is heated to reflux for 3.5 hours. Excess thionyl chloride is distilled off and the residue is fractionally distilled under reduced pressure. 102 g of product (87.2% yield of theory) are obtained in the form of a colorless liquid having a boiling point of 48 to 50 ° C./0.5 Torr.

Other compounds of the present invention listed in Table 1 may be obtained by methods similar to those of the above examples.

Example 4

Compounds of the present invention, listed in the following table, were tested at the rate of application of 5 kg of active ingredient per hectare in 600 liters per hectare of water in a greenhouse. ), Go, Pseudomonas (Go), Horodeum (Ho), Zea Mace (Ze), Tolium (Lo) and Pulp (Se) are used before and after germination. Results after three weeks of treatment in plants were evaluated by the following grades.

0 = no action.

1-2 = Plant growth is a condition that results in enhanced pigmentation of the first leaves, delayed lateral elongation of the shoots from the germinating or lower eye, decreased growth of irritated leaves and reduced root development.

3-4 = Plant no longer changes or is withered.

V = germination

N = after germination

The following compounds have a similar action.

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (N-ethyl-N-benzylamide).

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (N-benzyl-N-isopropylamide).

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (N-benzyl-N-butylamide).

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (3-methyl-benzylamide).

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (2-naphthyl-methylamide).

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (3,5-dimethyl-benzylamide).

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (4-tertbutyl-benzylamide).

Example 5

Plants listed in the following table are subjected to a series of experiments in a greenhouse at the application rate of 1 kg of active ingredient per hectare with the compounds indicated in the present invention before germination. For this purpose, the active compound is made into a suspension using 500 liters of water and applied uniformly to the soil. As a result, the compound of the present invention removes various plant species, in particular crop corn water cotton is not damaged. The result is a scale from 0 to 10, with 0 representing complete removal and 10 representing no damage at all.

0 = complete removal

10 = no damage

Example 6

4-Methyl-1,2,3-thiadiazole-5-carboxylic acid (cyclohexylmethylamide) and 4-methyl-1,2,3-thiadiazole-5-carboxylic acid (4-fluorobenzyl in a greenhouse Amides) are each suspended in 500 liters of water per hectare and then sprayed on the following plant species at the application rate of 1 kg of active ingredient per hectare. :

Stellaria, Senesio, Matrisara, Lamium, Centaurea, Amaranth, Calvum, Chrysanthem, Morning Glory, Polygonum, Brassica, Solumnum, Allium, Pisum, Porutulaca, Coquia, Doucus , Creanthus, Euphorbia tatura and chicory.

The plants are removed. After 2 days crop sorghum, cotton and soybeans are planted in the treated soil. Crops are intact and can grow without weeds.

Example 7

In the greenhouse, the plants listed in the following table were selected from 4-methyl-1,2,3-thiadiazole-5-carboxylic acid (cyclohexylmethylamide) and 4-methyl-1,2,3-thiadiazole-5-. Carboxylic acid (4-fluoro-benzylamide) is treated at an application rate of 1 kg of active ingredient per hectare.

Each active compound is sprayed uniformly at the rate of 500 liters per hectare in the form of an emulsion. Results show that grain, wheat, corn and rice remain undamaged and weeds are eliminated. The results are displayed in grades 0 through 10, with 0 representing complete removal and 10 representing undamaged status.

0 = completely removed

10 = undamaged

Example 8

Cotton that has begun to form potted flower buds is treated with the active ingredients in the doses indicated in the following table. (Repeat 4 times). The amount of water used as a carrier is 500 liters per hectare.

After a few days the percentage of defoliation is measured. The following table shows the superiority of the present invention compared to other compounds.

Claims (1)

The 1,2,3-thiadiazole-5-carboxylic acid halide, a compound of formula II, is reacted with a compound of formula III in the presence of an acid binder, or 1,2,3- compound of formula A process for preparing a compound of formula (I) characterized by reacting a thiadiazole-5-carboxylic acid ester with an amine of formula (VII).

Wherein R ₁ represents a hydrogen atom or represents an alkyl group containing at least one atom selected from oxygen and sulfur or substituted with at least one halogen atom, and X represents a group of -YR ₂ , wherein R ₂ represents a hydrogen atom , An unsubstituted or substituted alkyl group, an unsubstituted or substituted aryl group, an unsubstituted or substituted aryl-C ₁ -C ₂ -alkyl group, or a group of a monovalent metal, Y represents oxygen or sulfur and Z is halogen An atom and R ₃ and R ₄ each represent a hydrogen atom, an unsubstituted or substituted C ₁ -C ₁₈ alkyl group, a C ₂ -C ₈ alkenyl or alkynyl group unsubstituted or substituted C ₃ -C ₈ Cyclic aliphatic hydrocarbon group, unsubstituted or substituted aryl group, or R ₃ and R ₄ together with nitrogen represent morpholino, piperidino or pyrrolidino group.