GB2109792A - Herbicidal thiazolo- and [1,3]thiazino-[2,3-c][1,2,4]- triazinones - Google Patents

Abstract

Herbicidal preparations contain novel thiazolo- and [1,3]thiazino-[2,3- c][1,2,4]triazinones of the general formula I <IMAGE> (in which R1 represents C1-C6-alkyl optionally interrupted by O and/or S, free or esterified -COOH or alkyl- COOH, optionally alkyl-substituted C3-C8-cycloalkyl, or aromatic, aromatic-aliphatic or heterocyclic hydrocarbon which may be mono-, di- or polysubstituted by Hal and/or C1- C4-alkyl and/or C1-C4-alkoxy and/or C1-C4-alkylthio and/or -NO2, R2 represents H, C1-C6-alkyl or optionally substituted aromatic hydrocarbon, R3 represents H, C1-C6-alkyl, optionally substituted aromatic hydrocarbon, benzyl or -OH, R4 represents H, C1- C6-alkyl, optionally substituted aromatic hydrocarbon, benzyl, C1- C4-alkoxy or -OH, and n represents O or 1).

Description

SPECIFICATION Herbicidal preparations containing and methods using thiazolo- and [1 ,3]thiazino-[2,3-cj[1 2.4]- triazinones having a selective herbicidal action, new such compounds suitable therefor and the manufacture of these compounds The present invention is concerned with herbicidal preparations containing and methods using thiazolo- and [1 ,3]thiazino-[2,3-c][1 ,2,4]triazinones having a selective herbicidal action, with new such compounds suitable therefor and with the manufacture of these compounds.

Triazinones having a herbicidal action are already known (Belgian Patent Specifications Nos.

69 70 83 and 79 98 54). These herbicides do not, however, solve the problem of obtaining a good herbicidal action against troublesome weeds with, at the same time, a good compatability with regard to several agricultural principal crops used in a crop rotation system.

The problem upon which the present invention is based has therefore been to develop an agent which can be used against weeds that are difficult to control in several agricultural principal crops without damaging those crops.

This problem is solved according to the present invention by thiazolo- and[1 ,3]thiazino/2,3 c][1,2,4]triazinones of the general formula I

in which R1 represents a C1-C6-alkyl group which may be interrupted by at least one atom selected from oxygen and sulphur atoms, a free or esterified carboxyl group, an alkyl group substituted by a free or esterified carboxyl group, a C3-C8-cycloalkyl group which may be substituted by at least one alkyl group, an aromatic or aromatic-aliphatic hydrocarbon group which may be substituted by one or more substituents selected from halogen atoms and C1-C4-alkyl, C1-C4-alkoxy, C1-C4-alkylthio and nitro groups, or a hetercyclic hydrocarbon group which may be substituted by one or more substituents selected from halogen atoms and C1-C4-alkyl, C1-C4-alkoxy, C1-C4-alkylthio and nitro groups, R2 represents a hydrogen atom, a C1-C6-alkyl group or an unsubstituted or substituted aromatic hydrocarbon group, R3 represents a hydrogen atom, a C1-C6-alkyl group, an unsubstituted or substituted aromatic hydrocarbon group, or a benzyl or hydroxyl group, R4 represents a hydrogen atom, a C,C-alkyl group, an unsubstituted or substituted aromatic hydrocarbon group, or a benzyl, C1-C4-alkoxy or hydroxyl group, and n represents 0 or 1.

The compounds of the general formula I have a surprisingly excellent suitability for controlling troublesome weeds with a compatability especially with regard to soya beans, potatoes, cotton, maize and wheat, and in this respect are greatly superior to the known agents. These properties constitute a great technical advance.

It is known that for economic reasons the most important agricultural crops are used more and more in a narrow crop rotation system with one another. With regard to weed flora, this has the result that more and more specific accompanying flora develop. If among these, which is almost always the rule, there are weeds that are difficult to control using the present state of the art in the sphere of weed control, conditions arise that easily result in the dominance of such species. Attempts have been made to solve this problem, for example, by attempting a control using the normally maximum or even excess application quantities of herbicides. As a result, damage is often caused to the crops. Since the known herbicides can also act residually via the ground on the subsequent crop, this crop too often suffers damage.It is therefore desirable for an advanced herbicide to have a good activity against troublesome weeds while at the same time having a good compatability with respect to several agricultural principal crops that are used in a crop rotation system.

The compounds of the general formula I satisfy these requirements and are distinguished by a surprisingly good compatability with regard to the above-mentioned crops, it being possible to use them both in a pre-emergence and in a post-emergence method.

The herbicidal action extends to many species of weeds. There may be mentioned as species of troublesome weeds that can be controlled effectively, for exa mple, Abutilon theophrastii, lpomoea ssp., Solanum ssp., Viola ssp., Echinochloa crus galli, Setaria ssp., and Digitaria ssp.

The compounds may be used by incorporating them into the soil before the crop is sown or in a pre-emergence or post-emergence method.

The application quantities to be used for a selective weed control are approximately 0.1 to 5 kg of active substance per hectare. When two or more compounds of the general formula I are used, the range of 0.1 to 5 kg per hectare refers of course to the total application quantities.

In higher application quantities the compounds can also be used for a total weed control.

When used in lower application quantities, the compounds of the general formula I are also able to alter the natural development of plants in order to achieve different agnculturally or horticulturally noticeable properties. It will be understood that not every compound produces the same regulating actions in the case of every species of plant, the actions also being dependent upon the type of use, time of use and the concentration used. In general, the control of natural plant growth can be recognised visually by changes in the size, shape, colour or structure of the treated plant or parts thereof.The following may be mentioned as examples of changes in the development of plants produced by the compounds of the general formula I: inhibition of vertical growth; inhibition of root development, intensification of the stimulation of plant pigments, defoliation.

The present invention accordingly provides a herbicidal preparation, which comprises at least one compound selected from compounds of the general formula I in admixture or conjunction with a suitable carrier.

The present invention further provides a method of protecting a living plant against weeds and/or regulating the growth of the living plant, wherein the living plant and/or the area in the vicinity of the living plant is treated with at least one compound selected from compounds of the general formula I.

The present invention further provides a method of protecting an area of land against weeds and/or regulating the growth of living plants in the area, wherein the area is treated with at least one compound selected from compounds of the general formula I. The area of land may be a crop area, the crop being selected from, for example, soya bean, potato, cotton, maize and wheat crops.

Among the preferred compounds of the general formula I used in the herbicidal preparations and methods of the present invention there may be mentioned one or more of the following compounds: 3-phenyl-6,7-dihydro-4H-thiazolo[2,3-c] [ 1 ,2,4]triazin-4-one, 3-methyl-6,7-di hydro-4H-thiazolo[2,3-c] [ 1 ,2,4]triazin-4-one and 3-carbomethoxymethyl-6,7-di hydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

Most of the compounds of the general formula I are also included within the scope of the present invention, namely those compounds of the general formula I in which R1, R2, R3, R4 and n have the meanings given above, but with the proviso that when R2 and R4 each represents a hydrogen atom, n represents 0 and there is a single carbon-to-carbon bond in the 6,7-position, R1 does not represent a methyl, carbomethoxymethyl or phenyl group.

The present invention further provides a pack which comprises at least one compound selected from the compounds of the present invention, together with instructions for its use as a herbicide and/or for regulating the growth of a living plant.

Of the compounds of the general formula I, those that are especially distinguished by the properties described above are the compounds of the general formula I in which R, represents a C1- C6-alkyl group, for example methyl, trimethylmethyl, ethyl, propyl, isopropyl, methylpropyl, n-butyl, isobutyl, tert.-butyl, 2,2-dimethyl-1 -propyl, n-pentyl or n-hexyl, an acetic acid methyl ester group, an optionally alkyl-substituted C3-C8-cycloalkyl group, for example cyclopropyl, cyclopentyl, cyclohexyl, methylcyclohexyl or cyclooctyl, an optionally substituted aromatic hydrocarbon group, for example phenyl, 4-trimethylmethylphenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-methoxyphenyl, 4-methoxyphenyl, 4fluorophenyl, 4-iodophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 3,4dichlorophenyl, 3-nitrophenyl, 4-nitrophenyl, 1 -naphthyl or 2-naphthyl, an optionally substituted aromatic-aliphatic hydrocarbon group, for example benzyl or4-chlorobenzyl, a heterocyclic hydrocarbon group, for example thienyl or 2-furyl; R2 and/or R3 and/or R4 represents a hydrogen atom, a C1-C6-alkyl group, for example methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert.-butyl, 2,2dimethyl-1 -propyl, n-pentyl or n-hexyl, or an optionally substituted aromatic hydrocarbon group, for example phenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-methoxyphenyl, 4methoxyphenyl, 4-fluorophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chiorophenyl, 3,4-dichlorophenyl, 3-nitrophenyl or 4-nitrophenyl, and/or R4 represents a C1-C4-alkoxy group, for example methoxy, ethoxy, propoxy or n-butoxy, and/or R3 and/or R4 represents a hydroxyl group, and n represents 0 or 1.

Of these compounds, those that are distinguished by an outstanding action are the compounds of the general formula I in which R, represents a methyl, trimethylmethyl, methylpropyl, n-hexyl, cyclopentyl, cyclohexyl, phenyl, methylphenyl, trimethylmethylphenyl, methoxyphenyl, fluorophenyl, iodophenyl, chlorophenyl, nitrophenyl, benzyl or thienyl group, R2 represents a hydrogen atom or a methyl or phenyl group, R3 represents a hydrogen atom or a methyl or hydroxyl group, R4 represents a hydrogen atom or a methyl, dimethylmethyl, trimethylmethyl, phenyl, benzyl or hydroxyi group, and n represents 0 or 1.

The compounds of the general formula I may be used singly or in the form of mixtures with one another or with other active substances, Depending upon the desired purpose of application, there may be mentioned in this connection, for example, the following herbicidal active substances which may, if desired, even be added to the compounds of the general formula I only immediately before use:: substituted anilides, substituted anilines, substituted aryloxycarboxylic acids and salts, esters and amides thereof, substituted ethers, substituted arsonic acids and salts, esters and amides thereof, substituted benzimidazoles, substituted benzthiadiazinone dioxides, substituted benzoxazines, substituted benzoxazinones, substituted biurets, substituted quinolines, substituted carbamates, substituted aliphatic carboxylic acids and salts, esters and amides thereof, substituted N-arylsulphonyl-N'-triazinyl-urea derivatives, substituted aromatic carboxylic acids and salts, esters and amides thereof, substituted carbamoylalkyl-thio- or -dithio- phosphates, substituted quinazolines, substituted cycloalkylamidocarbothiolic acids and salts, esters and amides thereof, substituted cycloa lkylcarbonamido-thiazoles, substituted dicarboxylic acids and salts, esters and amides thereof, substituted dihydrobenzofuranyl sulphonates, substituted disulphides, substituted dipyridylium salts, substituted dithiocarbamates, substituted dithiophosphoric acids and salts, ester and amides thereof, substituted ureas, substituted hexa hydro-1 H-carbothioates, substituted hydantoins, substituted hydrazides, substituted hydrazonium salts, substituted isoxazolepyrimidones, substituted imidazoles, substituted isothiazolepyrimidones, substituted ketones, substituted naphthoquinones, substituted aliphatic nitriles, substituted aromatic nitriles, substituted oxadiazoles, substituted oxadiazinones, substituted oxadiazolidinediones, substituted oxadiazinediones, substituted phenols and salts and esters thereof, substituted phosphonic acids and salts, esters and amides thereof, substituted phosphonium chlorides, substituted phosphonalkylglycines, substituted phosphites, substituted phosphoric acids and salts, esters and amides thereof, substituted piperidines, substituted pyrazoles, substituted pyrazolealkylcarboxylic acids and salts, esters and amides thereof, substituted pyrazolium salts, substituted pyrazolium alkyl sulphates, substituted pyridazines, substituted pyridazones, substituted pyridinecarboxylic acids and salts, esters and amides thereof, substituted pyridines, substituted pyridine carboxylates, substituted pyridinones, substituted pyrimidines, substituted pyrimidones, substituted pyrrolidinecarboxylic acids and salts, esters and amides thereof, substituted pyrrolidines, substituted pyrrolidones, substituted arylsulphonic acids and salts, esters and amides thereof, substituted styrenes, substituted tetra hydro-oxadiazinediones, substituted tetrahydro-oxadiazolediones, substituted tetrahydromethanoindenes, substituted tetrahydro-diazole-thiones, substituted tetrahydro-thiadiazine-thiones, substituted tetrahydro-thiadiazolediones, substituted thiadiazoles, substituted aromatic thiocarboxyl ic acid amides, substituted thiocarboxylic acids and salts, esters and amides thereof, substituted thiolcarbamates, substituted thioureas, substituted thiophosphoric acids and salts, esters and amides thereof, substituted triazines, substituted triazoles, substituted uracils and substituted uretidinediones.

In addition, it is also possible to use other additives, for example non-phytotoxic additives that are capable of producing, with herbicides, a synergistic increase in action, for example wetting agents, emulsifiers, solvents and oily additives.

The active compounds of the general formula I or mixtures thereof are advantageously used in the form of 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 surfaceactive agents, for example wetting agents, adhesion-promoting agents, emulsifiers and/or dispersing agents.

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

Suitable solid carriers are, for example, mineral earths, for example tonsil, silica gel, talcum, kaolin, attapulgite, limestone and silicic acid, and vegetable products, for example meals.

As surface-active agents there may be mentioned for example, calcium ligninsulphonate, polyoxyethylenealkylphenol ethers, naphthalenesulphonic acids and salts thereof, phenolsuiphonic acids amd salts thereof, formaldehyde condensates, fatty alcohol sulphates and also substituted benzenesulphonic acids and salts thereof.

The total amount of the active substance or substances in the various preparations can vary within wide limits. For example, the preparations may contain approximately 5 to 95% by weight of active substance(s), approximately 95 to 5% 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 substances may be effected in a customary manner, for example with water as carrier in spraying liquor quantities of approximately 100 to 5000 litres per hectare. It is also possible to apply the active substances by the so-called low-volume method or ultra-low-volume method and it is equally possible to apply them in the form of so-called microgranules.

The following components, for example, are used to produce the preparations: Table I A. Wettable powder a) 80% by weight of active substance 15% by weight of kaolin 5% by weight of surface-active agents based on the sodium salt of N-methyl-N-oleyl-taurine and the calcium salt of ligninsulphonic acid, b) 50% by weight of active substance 40% by weight of clay minerals 5% by weight of cellulose pitch 5% by weight of surface-active agents based on a mixture of the calcium salt of ligninsulphonic acid with alkylphenyl-polyglycol ethers c) 20% by weight of active substance 70% by weight of clay minerals 5% by weight of cellulose pitch Table I (contd.) 5% by weight of surface-active agents based on a mixture of the calcium salt of ligninsulphonic acid with alkylphenyl-polyglycol ethers, d) 5% by weight of active substance 80% by weight of tonsil 10% by weight of cellulose pitch 5% by weight of surface-active agents based on a fatty acid condensation product.

B. Emulsion concentrate 20% by weight of active substance 40% by weight of xylene 35% by weight of dimethyl sulphoxide 5% by weight of a mixture of nonylphenyl-polyoxyethylene with calcium dodecylbenzene sulphonate.

The compounds of the general formula I may be manufactured, for example, by a) reacting a compound of the general formula II

in which R1 has the meaning given above, (i) with a compound of the general formula Ill

in which R2, R3, R4 and n have the meanings given above and Hal represents a halogen atom, in the presence of a base, or (ii) with a compound of the general formula IV

in which R2, R3, R4, n and Hal have the meanings given above, advantageously in the presence of a base, or (iii) when n represents 1 and there is a single carbon-to-carbon bond in each of the 6,7- and 7,8positions, with a compound of the general formula V

in which R2, R3, R4 and Hal have the meanings given above, advantageously in the presence of a base, and, if desired, separating any resulting isomers by column chromatography, or b) reacting a compound of the general formula VI

in which R, has the meaning given above and R represents a hydrogen atom or a C1C4-alkyl group, with a compound of the general formula VII

in which R2, R3, R4 and n have the meanings given above, or c) reacting a compound of the general formula VI

in which R1 and R have the meanings given above, with thiosemicarbazide of the formula H2N-NH-CS-NH2 to form a compound of the general formula VIII

in which R1 and R have the meanings given above, then reacting this compound of the general formula VIII either with a compound of the general formula III

in which R2, R3, R4, n and Hal have the meanings given above, in the presence of a base, or with a compound of the general formula IV

in which R2, R3, R4, n and Hal have the meanings given above, advantageously in the presence of a base, to form a compound of the general formula IX

in which Rr, R2, R3, R4, n and R have the meanings given above, and cyclising this compound of the general formula IX in the presence of a basic catalyst, or d) when R1 represents a group of the formula-CH2COOR', R' representing a hydrogen atom or a C-C4-alkyl group, reacting a compound of the general formula X F'OOC-C=-C-COOF' (X), in which R' has the meaning given above (that is acetylenedicarboxylic acid or an ester thereof), with a compound of the general formula VII

in which F2, R3, R4 and n have the meanings given above, to form a compound of the general formula XI

in which R2, R3, R4, n and R' have the meanings given above, cyclising this compound of the general formula XI in the presence of a base to form a compound of the general formula XII

in which R2, R3, R4, n and R' have the meanings given above, and isomerising this compound of the general formula XII.

There is accordingly also included within the scope of the present invention a process for the manufacture of the new compounds of the present invention by one of the variants a) to d) defined above.

The starting materials used for the manufacture of the compounds of the general formula I are known per sue or can be manufactured according to processes known per se.

The reaction between the reactants may take place between 0 and 120dC, but generally however between room temperature and the reflux temperature of the particular reaction mixture.

The duration of the reaction is from 1 to 72 hours.

For the synthesis of the compounds of the general formula I the reactants are advantageously used in approximately equimolar amounts. Suitable reaction media are solvents that are inert with respect to the reactants. The choice of solvents or suspension media depends upon the particular starting compounds used and on any acid acceptors or bases used. As solvents or suspension media there may be mentioned, for example, ethers, for example diethyl ether, diisopropyl ether, tetrahydrofuran and dioxan, aliphatic and aromatic hydrocarbons, for example petroleum ether, cyclohexane, hexane, heptane, benzene, toluene and xylene, carboxylic acid nitriles, for example acetonitrile, and carboxylic acid amides, for example dimethylformamide.

Suitable acid acceptors are organic bases, for example triethylamine, N,N-dimethylaniline and pyridine bases, or inorganic bases, for example oxides, hydroxides and carbonates of alkaline earth and alkali metals. Liquid bases, for example pyridine, can serve simultaneously as solvents.

In some cases in variants a) and c) as defined above, when using a reactant of the general formula IV or V, a hydroxyl group is introduced into the product by the action of the hypohalous acid formed as a by-product, so as to form a compound of the general formula I containing a hydroxyl substituent on the thiazole or [1,3]thiazine ring.

The compounds of the general formula I manufactured in accordance with the above-mentioned processes may be isolated from the reaction mixture by customary procedures, for example by distilling off the solvent used under normal or a reduced pressure or by precipitation with water.

As a rule, the compounds of the general formula I are colourless and odourless crystalline substances that are sparingly soluble in water and aliphatic hydrocarbons, and are moderately to readily soluble in halogenated hydrocarbons, for example chloroform and carbon tetrachloride, ketones, for example acetone, carboxylic acid amides, for example dimethylformamide, sulphoxides, for example dimethyl sulphoxide, carboxylic acid nitriles, for example acetonitrile, and lower alcohols, for example methanol and ethanol.

As solvents suitable for recrystallization there may be mentioned especially carbon tetrachloride, chloroform, toluene, acetonitrile and ethyl acetate.

The following Examples 1 to 11 illustrate the invention. These Examples illustrate the manufacture of the compounds of the present invention.

Example 1 302 g (3.6 moles) of sodium bicarbonate and 137.5 g (0.72 mole) of dibromoethane were introduced into 700 ml of 2-propanol and this suspension was heated to reflux. To this boiling mixture there was then added dropwise a mixture consisting of 61 g (0.36 mole) of 3-mercapto-6-(4 methylphenyl)-4,5-dihydro-[1 ,2,4]triazin-5-one, 146 ml of a 10% sodium hydroxide solution and 1 500 mi of 60% strength aqueous 2-propanol. The whole was then heated at the reflux temperature for 2 hours, filtered off from undissolved sodium bicarbonate and concentrated to dryness in vacuo. The resulting solid residue was washed with 500 ml of a 5% sodium hydroxide solution and again filtered.

The residue was separated by column chromatography over silica gel, using ethyl acetate as the eluant.

28.8 g (32% of the theoretical yield) of 3-(4-methylphenyl)-6,7-dihydro-4H-thiazolo[2,3-cj [1 ,2,4]- triazin-4-one were obtained.

Melting point: 1 930C.

Example 2 480 g (0.21 mole) of 3-mercapto-6-(4-methoxyphenyl)-4,5-dihydro-[1 ,2,4]triazin-5-one and 100 g (0.5 mole) of 1,3-dibromopropane were reacted in a manner analogous to the reaction conditions given in Example 1. After chromatographic separation, 7.7 g (14% of the theoretical yield) of 3-(4-methoxyphenyl)-4,6,7,8-tetrahydro-4H-[ 1 ,3jthiazino[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 181 C.

Example 3 18.5 g (0.1 mole) of 3-mercapto-6-trimethylmethyl-4,5-dihydro-[1 ,2,4]triazin-5-one, 432 g (0.2 mole) of 2,3-dibromobutane and 258 g (0.2 mole) of ethyldiisopropylamine were dissolved in 200 ml of acetonitrile and heated at the reflux temperature for 48 hours. The mixture was poured into ice water and the precipitate that formed was filtered off and separated by chromatography over silica gel, using ethyl acetate as the eluant. 8.1 g (34% of the theoretical yield) of 3-trimethylmethyl-6,7-dihydro 6,7-di methyl-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 1 340C.

Example 4 19.8 g (0.1 mole) of 2-hydrazino-4-,5-dhydrothiazole hydrobromide were dissolved in 200 ml of ethanol, and then, in succession, 20 ml of a 10% aqueous sodium hydroxide solution and 23.4 g (0.1 mole) of 4-trimethylmethylphenyl-glyoxylic acid ethyl ester were added and the whole was heated at the reflux temperature for 4 hours, then poured into ice water and the precipitate that formed was filtered off and recrystallised from ethyl acetate. 18.5 g (65% of the theoretical yield) of 3-(4-trimethyl methylphenyl)-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 2030C.

Example 5 19.6 g (0.1 mole) of 2-hydrazinothiazole hydrobromide and 16.4 g (0.1 mole) of phenyl-glyoxylic acid methyl ester were reacted in a manner analogous to that described in Example 3. 9.8 g (43% of the theoretical yield) of 3-phenyl-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one were obtained.

Melting point: 181 C.

Example 6 12.9 g (0.1 mole) of 2-hydrazino-2,4,5,6-tetrahydro-2H-[1 ,3]thiazine and 16.4 g (0.1 mole) of phenyl-glyoxylic acid methyl ester were reacted in a manner analogous to that described in Example 3.

18.4 g (75% of the theoretical yield) of 3-phenyl-4,6,7 ,8-tetra hydro-4H-[l ,3]thiazino[2,3-c] [1 ,2,4]- triazin-4-one were obtained.

Melting point: 1 550C.

Example 7 20.5 g (0.1 mole) of 3-mercapto-6-phenyl-4,5-dihydro[1 ,2,4jtriazin-5-one, 18.4 g (0.2 mole) of chloroacetone and 80 ml of a 10% aqueous sodium hydroxide solution were stirred in 250 ml of ethanol at 600C for 3 hours. The whole was then acidified with dilute hydrochloric acid and the resulting reaction solution was cooled. The precipitate that formed was filtered off and separated by column chromatography over silica gel, using acetone/petroleum ether (1:1) as the eluant. 5.10 g (21% of the theoretical yield) of 3-phenyl-6-methyl-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 1 580C.

Example 8 In a manner analogous to that described in Example 7, 20.5 g (0.1 mole) of 3-mercapto-6 phenyl-4,5-dihydro[1 ,2,4]triazin-5-one were reacted with 39.8 g (0.2 mole) of bromoacetophenone.

After separation by column chromatography, 4.58 g (1 5% of the theoretical yield) of 3,6-diphenyl-4H- thiazolo[2,3-c][ 1 ,2,4]triazin-4-one were obtained.

Melting point: 1250C.

Example 9 20.4 g (0.1 mole) of 3-mercapto-6-phenyl-4,5-dihydro[1 ,2,4]triazin-5-one were dissolved in 100 ml of dioxan plus 100 ml of dimethylformamide, 20 ml of a 50% strength chloroacetaldehyde solution were added and the whole was stirred at 600C for 6 hours. The reaction mixture was introduced into ice water and the precipitate that formed was separated by column chromatography, using ethyl acetate/methanol (9:1) as the eluant. 3.7 g (15% of the theoretical yield) of 3-phenyl-6-hydroxy-6,7 dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 2130C.

Example 10 1 5 g (0.073 mole) of 3-mercapto-6-phenyl-4,5-dihydro-[1 ,2,4]triazin-5-one were dissolved at an elevated temperature in 800 ml of acetonitrile, 13.5 g (0.15 mole) of epichlorohydrin and 14.85 g (0.115 mole) of ethyldisopropylamine were added and the whole was reacted at 60"C for 16 hours.

The reaction mixture was concentrated in vacuo and the residue was separated by column chromatography over silica gel (system: ethyl acetate/ethanol 9:1). 3.6 g (19% of the theoretical yield) of 3-phenyl-7-hydroxy-4,6,7,8-tetrahydro-4H-[ 1 ,3]thiazino[2,3-c] [1 ,2,4]triazin-4-one having a melting point of 181 OC were obtained.

Example 11 15 g (0.1 mole) of phenyl-glyoxylic acid were dissolved in 1 litre of ethanol. A solution of 9.1 g (0.1 mole) of thiosemicarbazide in 500 ml of 5% strength aqueous acetic acid was then added thereto and this reaction solution was stirred at 900C for 1 5 minutes. After cooling, half of the solvent was removed in vacuo and the precipitate that formed was filtered off, washed with water and dried at 500 C. Without further purification, the resulting thiosemicarbazone was then dissolved in 120 ml of a 5% soda solution, 9.2 g (0.1 mole) of chloroacetone in 50 ml of ethanol were added and the whole was stirred at 600C for 2 hours. The whole was cooled, then acidified with 10% strength hydrochloric acid and the precipitate that formed was filtered off.The precipitate was dissolved in a mixture of 200 ml of pyridine/acetic anhydride (1:1) and the whole was stirred at 600C for 3 hours. The reaction mixture was then poured into 500 ml of ice water and the precipitate that formed was filtered off, washed with water and recrystallized from ethyl acetate. 12.9 g (53% of the theoretical yield) of 3-phenyl-6-methyl 4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one having a melting point of 1 580C were obtained.

Each of the following compounds of the present invention may be manufactured in a manner analogous to that described in any one of the appropriate Examples 1 to 11 using the corresponding starting materials: Physical Name of compound constant 3-Trimethylmethyl-6,7-dihydro-4H-thlazolo[2,3-cl[1,2,4]triazin-4-one m.p.: 122 C 3-(4-Methoxyphenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.: 188 C 3-(4-Chlorophenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.: 184 C 3-Benzyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.: 135 C 3-Cyclohexyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one m.p.: 1 780 C 3-Thienyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.:203 C 3-(4-Fluorophenyl)-4,6,7,8-tetrahydro-4H-[ 1 ,3]thiazino[2,3-c][ 1 ,2,4]triazin-4-one m.p.: 2030C 3-(4-Nitrophenyl)-4,6,7,8-tetrahydro-4H-[ 1 ,3]thiazino[2,3-c][1 ,2,4jtriazin-4-one m.p.: 2360 C 3-Cyclopentyl-4,6,7,8-tetrahydro-4H-[1,3]thiazino[2,3-c][1,2,4]triazin-4-one m.p.:183 C 3-Trimethylmethyi-4,6,7,8-tetrahydro-4H- 1,3]thiazino[2,3-c][@ ,2,4]triazin-4-one m.p.: 1480 C 3-Haxyl-4,6,7,8-tetrahydro-4H-[1,3]-thiazino[2,3-c][ 1 ,2,4jtriazin-4-one m.p.: 121 0C 3-(4-lodophenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.: 21 50C 3-Cyclopentyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.: 171 0C 3-(2-Methylpropyl)-6,7 -dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one m.p.: 1 540 C 3-Trimethylmethyl-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.:151 C 3-(2-Fluorophenyl)-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.:181 C 3-(2-Methylphenyl)-4H-thiazolo[2,3-c][1,2,4]triazin-4one m.p.:150 C 3-Phenyl-6-methyl-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4]triazin-4-one m.p.: 11 40C 3-Phenyl-6-dimethylmethyl-6,7-dihydro-4H-thlazolo[2,3-c][1,2,4]triazin 4-one m.p.: 1320C 3-Phenyl-6-trimethylmethyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin 4-one m.p.: 1300C 3-Phenyl-6-benzyl-6,7-dihydro-4H-thlazolo[2,3-c][1 ,2,4]triazin-4-one m.p.: 11 50C 3,7-Diphenyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one m.p.:124 C 3-Phenyl-7-methyl-4,6,7,8-tetrahydro-4H-[1,3]thiazinol][2,3-c][1,2,4] triazin-4-one m.p.: 1380C 3-Cyclohexyl-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one m.p.: 1250C 3-Trimethylmethyl-6-methyl-4H-thiazolo[2,3-c][ 1 ,2,4jtriazin-4-one m.p.: 1 280 C 3-Trimethylmethyl-6-methyl-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]- triazin-4-one m.p.: 1120C 3-Ethyl-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one m.p.: 1 000C 3-isopropyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one 1 -(6,7-Dihydro-4-oxo-4H-thiazolo[2,3-c] [1,2,4]triazln-3yl)-formic acid ethyl ester m.p.: 1050C 2-(6,7-dihydro-4-oxo-4H-thiazolo[2,3-c][1,2,4]triazin-3-yl)-propionic acid ethyl ester m.p.: 1100C 3-P henyl-6-ethyl-6,7-di hydro-4H-thiazo lo [2,3-c] [1 ,2,4]triazin-4one m.p.: 1 790 C 3-Phenyl-6,7-dimethyl-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one m.p.: 1 550C 3-(4-Fluorophenyl)-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one m.p.: 1 890C 3-(2,4-Dichlorophenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one m.p.: 2420C 3-(2,4-Dichlorophenyl)-4H-thiazolo[2,3-c][1,2,4]triazin-4-one 3-(2,4-Dichlorophenyl)-6-methyl-6,7-dihydro-4H-thiazolo[2,3-c][ 12,4]- triazin-4-one m.p.: 1560C 3-(5-Chloro-2-thienyl)-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4jtriazin-4-one m.p.: 1 950 C 3-(2,5-Dichloro-3-thienyl)-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4]triazin- 4-one m.p.: 1760C 3-(3-Methylphenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one 3-(1-Methylcyclohexyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4 one m.p.: 1130C The following Examples 12 to 1 6 describe the manufacture of known compounds of the general formula I that can be used in accordance with the present invention.

Example 12 302 g (3.6 moles) of sodium bicarbonate and 137.5 g (0.72 mole) of dibromoethane were introduced into 700 ml of 2-propanol and this suspension was heated to reflux. To this boiling mixture there was then added dropwise a mixture consisting of 73.8 g (0.36 mole) of 3-mercapto-6-phenyl 4,5-dihydro[1 ,2,4]triazin-5-one, 146 ml of a 10% sodium hydroxide solution and 1 500 ml of 60% strength aqueous 2-propanol. The whole was then heated at the reflux temperature for 2 hours, filtered off from undissolved sodium bicarbonate and concentrated to dryness in vacuo. The resulting solid residue was washed with 500 ml of a 5% sodium hydroxide solution and again filtered.The residue was separated by column chromatography over silica gel, using ethyl acetate as the eluant. 28.8 g (34% of the theoretical yield) of 3-phenyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 1 350C.

Example 13 Ion a manner analogous to that described in Example 12,14.3 g (0.1 mole) of 3-mercapto-6 methyl-4,5-dihydro[1 ,2,4jtriazin-5-one were reacted to form 7.4 g (44% of the theoretical yield) of 3 methyl-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one.

Melting point 171 C.

Example 14 19.8 g (0.1 mole) of 2-hydrazino-4,5-dihydrothiazole hydrobromide were dissolved in 200 ml of ethanol, and then, in succession, 80 ml of a 10% aqueous sodium hydroxide solution and 10.2 g (0.1 mole) of pyruvic acid methyl ester were added and the whole was brought to the boil and then cooled.

The precipitate that formed was filtered off and recrystallized from ethyl acetate. 11.0 g (65% of the theoretical yield) of 3-methyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one were obtained.

Melting point: 171 C.

Example 15 In a manner analogous to the described in Example 14, 1 6.4 g (0.1 mole) of phenyl-glyoxylic acid methyl ester were reacted with 19.8 g (0.1 mole) of 2-hydrazino-4,5-dihydrothiazole hydrobromide to form 13.2 g (57% of the theoretical yield) of 3-phenyl-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4ltriazin-4- one.

Melting point: 1350C.

Example 16 40 g (0.2 mole) of 2-hydrazino-4,5-dihydrothiazole hydrobromide were dissolved in 500 ml of a 2% sodium hydroxide solution; this solution was cooled to 50C and 28 g (0.2 mole) of acetylenedicarboxylic acid methyl ester were added dropwise thereto and the whole was stirred at 250C for 2 hours. The precipitate that formed was filtered off and dissolved in 250 ml of methanol; 25 ml of triethylamine were added and the whole was stirred at 250C for 1 hour. The precipitate that formed was again filtered off, and then boiled under reflux in 500 ml of methanol for 1 hour.The solvent was then removed in vacuo and the residue that remained was recrystallized from ethyl acetate. 24.1 g (53% of the theoretical yield) of 3-carbomethoxymethyl-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]triazin- 4-one having a melting point of 1 230C were obtained.

The following Examples also illustrate the invention. These Examples illustrate the possible applications for the compounds of the general formula I in the form of preparations as mentioned above.

Example 17 In each of two series of tests carried out in a greenhouse, the compounds of the general formula I listed in the Table below were in each case sprayed in an application quantity of 5 kg of active substance per hectare dissolved in 500 litres of water per hectare on to the test plants Sinapsis (SiJ, Solanum (So) and Setaria (Se); one of the series of tests was carried out according to the preemergence method and the other according to the post-emergence method. 3 weeks after the treatment, the results of the treatment were evaluated and expressed by a numerical scale extending from 0 to 4, according to which 0=no action, and 4=destruction of the plant.

As can be seen from the Table, as a rule the test plants were destroyed.

Compound of general formula I Pre-emergence Post-emergence Se Si So Se Si So 3-Phenyl-4-,6,7,8- 4 4 4 4 4 4 tetrahydro-4H-[1,3]- thiazino[2,3-c] [1 ,2,4]triazin-4-one 3-Phenyl-6,7-dihydro- 4 4 4 4 4 4 4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-Phenyl-6-methyl- 4 4 4 4 4 4 6,7-dihydro-4H thiazolo[2,3-c][1 ,2,4]- triazin-4-one 3-(4-Chlorophenyl)- 4 4 4 4 4 4 6,7-dihydro-4H thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-Carbomethoxymethyl- - 4 4 - - 6,7-dihydro-4H-thiazolo [2,3][1 ,2,4]- triazin-4-one 3-Thienyl-6,7-dihydro- - - - 4 4 4 4H-thiazolo[2,3-c] [1,2,4]triazin-4-one 3-(3-Methylphenyl)- 4 4 4 4 4 4 6,7-dihydro-4H thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-(1-Methylcyclo- 4 4 4 4 4 4 hexyl)-6,7-dihydro 4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-(2,4-Dichlorophenyl)- 4 4 4 4 4 4 4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-Cyclohexyl-4H- 4 4 4 4 4 4 thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-Trimethylmethyl-6- 4 4 4 4 4 4 methyl-6,7-dihydro 4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-lsopropyl-6,7- 4 4 4 4 4 4 dihydro-4H-thiazolo [2,3-c][1 ,2,4]- triazin-4-one 3-Phenyl-6,7-dimethyl- 4 4 4 4 4 4 4H-thiazolo[2,3-c] [1,2,4]triazin-4-one 3-(4-Fluorophenyl)- 4 4 4 4 4 4 6,7-dihydro-4H thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-(2,4-Dichlor- 4 4 4 4 4 4 phenyl)-6,7-dihydro 4H-thiazolo[2,3-c]- [1 ,2,4]triazin-4-one 3-(2,4-Dichloro- 4 4 4 4 4 4 phenyl)-6-methyl-6,7 dihydro-4H-thiazolo [2,3-c][1,2,4]- triazin-4-one Compound of general formula I Pre-emergence Post-emergence Se Si So Se Si So 3-(5-Chloro-2-thienyl)- 4 4 4 4 4 4 6,7-dihydro-4H-[2,3-c] [1 ,2,4]triazin-4-one 3-(2,5-Dichloro-3- 4 4 4 4 4 4 thienyl)-6,7-dihydro 4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-Trimethylmethyl- 4 4 4 4 4 4 4,6,7,8-tetrahydro-4H [1,3]thiazino[2,3-c]- [1 ,2,4]triazin-4-one 3-Cyclopentyl-6,7- 4 4 4 4 4 4 dihydro-4H-thiazolo [2,3-c] [1,2,4]- triazin-4-one 3-Trimethylmethyl- 4 4 4 4 4 4 6,7-dihydro-4H thiazolo[2,3-c] [1 ,2,4]triazin-4-one 3-Cyclohexyl-6,7- 4 4 4 4 4 4 dihydro-4H-thiazolo [2,3-c][1,2,4]- triazin-4-one 3-Thienyl-6,7- 4 4 4 4 4 4 dihydro-4H-thiazolo [2,3-c][1 ,2,4]- triazin-4-one 3-Trimethylmethyl- 4 4 4 4 4 4 4H-thiazolo[2,3-c]- [1 ,2,4]triazin-4-one 3-(2-Methylpropyl)- 4 4 4 4 4 4 6,7-dihydro-4H thiazolo[2,3-c] [1 ,2,4]triazin-4-one Untreated 0 0 0 0 0 0 Example 18 In a series of tests carried out in a greenhouse, the pants listed in the Table below were treated before their emergence with the listed compounds of the general formula I and the known compound used for comparison, there being used in each case an application quantity of 0.3 or 1 kg of active substance per hectare. For this purpose, the compounds were in each case applied uniformly to the soil in the form of an aqueous solution or suspension using 500 litres of water per hectare.

The results of the treatment were assessed and expressed by a numerical scale extending from 0 to 10, the value 0 representing total destruction of the plant and the value 10 representing no damage.

The results show that, in contrast to the compound used for comparison, the compounds of the general formula I exhibit an improved compatability with respect to the crop plants and an improved action with respect to the weeds.

Compound of general formula 1 3-Phenyl-6,7-dihydro-4H- 1 10 10 10 10 - - - 0 0 0 0 0 0 0 thiazolo[2,3-c][1,2,4] triazin-4-one 3-Phenyl-4,6,7,8-tetra- 1 10 10 10 10 - - - - 0 0 0 0 0 0 0 hydro-4H-[1,3]thiazino [2,3-c][1,2,4]triazin-4-one 3-Phenyl-6-methyl-6,7- 0.3 10 10 10 10 10 10 10 0 0 0 0 0 0 0 dihydro-4H-thiazolo[2,3-c] [1,2,4]triazin-4-one 3-Trimethylmethyl-6,7- 0.3 10 10 10 - - - - 0 0 0 0 0 0 0 dihydro-4H-thiazolo[2,3-c] [1,2,4]triazin-4-one 3-Trimethyklmethyl- 0.3 10 10 10 - - - - 0 0 0 0 0 0 0 methyl-6,7-dihydro-4H thiazolo[2,3-c][1,2,4] triazin-4-one Agent for comparison 4-Amino-6-phenyl-4,5- 1 8 0 7 8 - - - 5 7 0 0 8 10 7 dihydro-3-methyl-1,2,4 triazin-5-one (Belgian Patent Speciflcation No.7998 54)

Example 19 In a series of tests carried out in a greenhouse, the plants listed in the Table below were treated after their emergence with the listed compounds of the general formula I and the known compound used for comparison, there being used in each case an application quantity of 0.3 or 1 kg of active substance per hectare. For this purpose, the compounds were in each case sprayed uniformly over the plants in the form of an aqueous solution or suspension using 500 litres of water per hectare.

Again, the results of the treatment were assessed and expressed by a numerical scale extending from 0 to 10, the value 0 representing total destruction of the plant and the value 10 representing no damage.

In this case too, 3 weeks after the treatment, the compounds of the general formula I displayed a high selectivity while having an excellent action against the weeds. The agent used for comparison did not exhibit this selectivity.

Compound of general formula 1 3-Phenyl-6,7-dihydro-4H- 1 10 10 10 - - - - 0 0 0 0 0 0 0 thiazolo[2,3-c][1,2,4] triazin-4-one 3-Phenyl-4,6,7,8-tetra- 1 10 10 10 10 - - - 0 0 0 0 0 0 1 hydro-4H-[1,3]thiazino [2,3-c][1,2,4]triazin-4-one 3-Phenyl-6-methyl-6,7- 0.3 10 - - - 10 10 10 0 0 0 0 0 0 0 dihydro-4H-thiazolo[2,3-c] [1,2,4]triazin-4-one 3-Cyclohexyl-6,7-dihydro- 1 10 10 - - 10 10 10 0 0 0 0 0 0 0 4H-thiazolo[2,3-c][1,2,4] triazin-4-one 3-Cyclohexyl-4H-thiazolo- 1 10 10 - - 10 10 10 0 0 0 0 0 0 0 [2,3-c][1,2,4]triazin-4-one 3-Cyclopentyl-6,7- 1 10 10 - - 10 10 10 0 0 0 0 0 0 0 dihydro-4H-thlazolo [2,3-c][1,2,4]thiazin-4-one 3-Thienyl-6,7-dihydro- 1 10 10 - - 10 10 10 0 0 0 0 0 0 0 4H-thizolo[2,3-c] [1,2,4]triazin-4-one 4-Amino-6-phenyl- 1 7 5 4 8 - - - 1 3 0 0 10 10 8 4,5-dihydro-3-methyl 1,2,4-triazin-t-one (Belgian Patent Specification No. 79 98 54)

Claims (85)

Claims

1. A thiazolo- or [1,3]thiazino-[2,3-c][1,2,4]triazinone of the general formula I

in which F1 represents a C1-C6-alkyl group which may be interrupted by at least one atom selected from oxygen and sulphur atoms, a free or esterified carboxyl group, an alkyl group substituted by a free or esterified carboxyl group, a C3-C8-cycloalkyl group which may be substituted by at least one alkyl group, an aromatic or aromatic-aliphatic hydrocarbon group which may be substituted by one or more substituents selected from halogen atoms and C1-C4-alkyl, C1-C4-alkoxy, C1-C4-alkylthio and nitro groups, or a heterocyclic hydrocarbon group which may be substituted by one or more substituents selected from halogen atoms and C1-C4-alkyl, C1-C4-alkoxy, C1-C4-alkylthio and nitro groups, R2 represents a hydrogen atom, a C1C6-alkyl group or an unsubstituted or substituted aromatic hydrocarbon group, R3 represents a hydrogen atom, a C1-C6-alkyl group, an unsubstituted or substituted aromatic hydrocarbon group, or a benzyl or hydroxyl group, R4 represents a hydrogen atom, a C1-$C5-alkyl group, an unsubstituted or substituted aromatic hydrocarbon group, or a benzyl, C1-C4-alkoxy or hydroxyl group, and n represents 0 or 1, with the proviso that when R2 and R4 each represents a hydrogen atom, n represents 0 and there is a single carbon-to-carbon bond in the 6,7-position, R1 does not represent a methyl, carbomethoxymethyl or phenyl group.

2. A compound as claimed in claim 1, wherein R1 represents a methyl, trimethylmethyl, methylpropyl, n-hexyl, cyclopentyl, cyclohexyl, phenyl, methylphenyl, trimethylmethylphenyl, methoxyphenyl, fluorophenyl, chlorophenyl, iodophenyl, nitrophenyl, benzyl or thienyl group, R2 represents a hydrogen atom or a methyl or phenyl group, R3 represents a hydrogen atom or a methyl or hydroxyl group, R4 represents a hydrogen atom or a methyl, dimethylmethyl, trimethylmethyl, phenyi, benzyi or hydroxyl group, and n represents 0 or 1, with the proviso that when R2 and R4 each represents a hydrogen atom, n represents 0 and there is a single carbon-to-carbon bond in the 6,7-position, R1 does not represent a methyl or phenyl group.

3,3-(4-Methylphenyl),8,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

4. 3-Trimethylmethyl-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4]triazin-4-one.

5,3-(4-Methoxyphenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]trlazin-4-one.

6.3-(4-Chlorophenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

7.3-Benzyl-6,7-dihydro-4H-thiaolo[2,3-c][1,2,4,]triazin-4-one.

8. 3-Cyclohexyl.6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]triazin-4one.

9. 3-Thienyl-6,7-dihydro-4H-thiazolo[2,3-cl 1 ,2,4]triazin-4-one.

10.3-(4-Methoxyphenyl)-4,6,7,8-tetrahydro-4H-[1,3]thiazino[2,3-c][1,2,4]triazin-4-one

11. 3-(4-Fluorophenyl)-4,6,7,8-tetrahydro-4H-[ 1 ,3]thiazino[2,3-cj[1 ,2,4]triazin-4-one.

12.3-(4-Nitrophenyl)-4,6,7,8-tetrahydro-4H-[1,3]thiazino[2,3-c] [1 ,2,4]triazin-4-one.

13,3-Phenyl-4,6,7,8-tetrahydro-4H-[1,3]thiazino[2,3-c][1,2,4]triazin-4-one.

14. 3-Cyclopentyl-4,6,7,8-tetrahydro-4H-[1 ,3]thiazino[2,3-c][1 ,2,4]triazin-4-one.

1 5. 3-Trimethylmethyl-4,6,7,8-tetrahydro-4H-[1 ,3]thiazino[2,3-c] [1 ,2,4]triazin-4-one.

1 6. 3-Hexyl-4, 6,7,8-tetra hyd ro-4H-[l ,3]thiazi no] [2,3-c] [1 ,2,4]triazin-4-one.

17,3-(4-Trimsthylmethylphenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-one.

18.3-(4-iodophenyl)-6,7-dihydro-4H-thlazolo[2,3-c][1,2,4]triazin-4-one.

1 9. 3-Cyclopentyl-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4]triazin-4-one.

20.3-(2-Methylpropyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

21,3-Phenyl-4H-thlazolo[2,3-c][1,2,4]triazin-4-one.

22. 3-Trimethylmethyl-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

23. 3-(2-Fluorophenyl)-4H-thiazolo[2,3-c][ 1 ,2,4]triazin-4-one.

24.3-(2-Methylphenyl)-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

25.3-Trimethylmethyl-6,7-dimethyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one

26.3-Phenyl-6-methyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

27.3,7-Diphenyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

28. 3-Phenyl-6-methyl-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

29,3,6-diphenyl-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

30. 3-Phenyl-6-hydroxy-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

31. 3-Phenyl-7-hydroxy-4,6,7,8-tetrahydro-4H 1,3]thiazino[2,3-c][1 ,24]triazin-4-one.

32.3-Phenyl-6-dimethylmethyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

33.3-Phenyl-6-trimethylmethyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

34.3-Phenyl-6-benzyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

35. 3-Phenyl-7-methyl-4,6,7,8-tetra hydro-4H-[ 1 ,3]thiazino[2,3-c] [1 ,2,4]triazin-4-one.

36. 3-Cyclohexyl-4H-thiazolo[2,3,-c] [1 ,2,4]triazin-4-one.

37.3-Trimethylmethyl-6-methyl-4H-thlazolo[2,3-c][1,2,4]trlazln-4-one.

38. 3-Trimethylmethyl-6-methyl-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4jtriazin-4-one.

39. 3-Ethyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

40. 3-lsopropyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

41. 1 -(6,7-Dihydro-4-oxo-4H-thiazolo[2,3-c][1 ,2,4]triazin-3-yl)-formic acid ethyl ester.

42. 2-(6,7-Dihydro-4-oxo-4H-thiazolo[2,3-c] [1 ,2,4]triazin-3-yl)-propionic acid ethyl ester.

43. 3-Phenyl-6-ethyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

44.3-Phenyl-6,7-dimethyl-4H-thiazolo[2,3-c][1,2,4,]triazln-4-one.

45.3-(4-Fluorophenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1.2,4]triazin-4-one.

46.3-(2,4-Dichlorophenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

47.3-(2,4-Dichlorophenyl)-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

48. 3-(2,4-Dichlorophenyl)-6-methyl-6,7-dihydro-4H-thiazolo[2,3-c][ 1 ,2,4]triazin-4-one.

49.3-(5-Chloro-2-thienyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

50.3-(2,5-Dichloro-3-thienyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

51,3-(3-Methylphenyl)-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

52. 3-( 1 -Methylcyclohexyl )-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one.

53. A herbicidal preparation which comprises at least one compound selected from compounds of the general formula I

in which R1 represents a C1-C6-alkyl group which may be interrupted by at least one atom selected from oxygen and sulphur atoms, a free or esterified carboxyl group, an alkyl group substituted by a free or esterified carboxyl group, a C3-C8-cycloalkyl group which may be substituted by at least one alkyl group, an aromatic or aromatic-aliphatic hydrocarbon group which may be substituted by one or more substituents selected from halogen atoms and C1-C4-alkyl, C1C4-alkoxy, C1-C4-alkylthio and nitro groups, or a heterocyclic hydrocarbon group which may be substituted by one or more substituents selected from halogen atoms and C1-C4-alkyl, C1-C4-alkoxy, C,C4-alkylthio and nitro groups, R2 represents a hydrogen atom, a C1-C6-alkyl group or an unsubstituted or substituted aromatic hydrocarbon group, R3 represents a hydrogen atom, a C1-C6-alkyl group, an unsubstituted or substituted aromatic hydrocarbon group, or a benzyl or hydroxyl group, R4 represents a hydrogen atom, a C1-C8-alkyl group, an unsubstituted or substituted aromatic hydrocarbon group, or a benzyl, C1-C4-alkoxy or hydroxyl group, and n represents 0 or 1, in admixture or conjunction with a suitable carrier.

54. A preparation as claimed in claim 53, wherein R1 represents a methyl, trimethylmethyl, methylpropyl, n-hexyl, cyclopentyl, cyclohexyl, phenyl, methylphenyl, trimethylmethylphenyl, methoxyphenyl, fluorophenyl, chlorophenyl, iodophenyl, nitrophenyl, benzyl or thienyl group, R2 represents a hydrogen atom or a methyl or phenyl group, R3 represents a hydrogen atom or a methyl or hydroxyl group, R4 represents a hydrogen atom or a methyl, dimethylmethyl, trimethylmethyl, phenyl, benzyl or hydroxyl group, and n represents 0 or 1.

55. A herbicidal preparation which comprises the compound claimed in any one of claims 3 to 52, in admixture or conjunction with a suitable carrier.

56. A herbicidal preparation which comprises at least one compound selected from 3-P henyl-6,7-dihydro-4H-thiazolo[2,3-c] [1 ,2,4]triazin-4-one, 3-Methyl-6,7-di hydro-4H-thiazolo[2 ,3-c][1,2 4]triazin-4-one and 3-Carbomethoxymethyl-6,7-dihydro-4H-thiazolo[2,3-c] [1,2,4]triazin-4-one, in admixture or conjunction with a suitable carrier.

57. A preparation as claimed in any one of claims 53 to 56, which is in the form of a powder, a strewable preparation, granules, a solution, an emulsion or a suspension.

58. A preparation as claimed in any one of claims 53 to 57, which also contains one or more active substances selected from herbicides other than compounds of the general formula I.

59. A preparation as claimed in any one of claims 53 to 58, wherein the total amount present of active substance or substances is approximately 5 to 95% by weight.

60. A preparation as claimed in any one of claims 53 to 59, containing one or more surfaceactive agents in a total amount of up to 20% by weight.

61. Any one of the preparations as claimed in claim 53 and substantially as described in Table I herein.

62. Any one of the preparations as claimed in claim 53 and substantially as described in Examples 17 to 19 herein.

63. A method of protecting a living plant against weeds and/or regulating the growth of the living plant, wherein the living plant and/or the area in the vicinity of the living plant is/are treated with at least one compound selected from compounds of the general formula I given in claim 53, in which R, R2, R3, R4 and n have the meanings given in claim 53.

64. A method as claimed in claim 63, wherein R" R2, R3, R4 and n have the meanings given in claim 54.

65. A method as claimed in claim 63, wherein the treatment is carried out with the compound claimed in any one of claims 3 to 52.

66. A method as claimed in claim 63, wherein the treatment is carried out with at least one compound selected from 3-Phenyl-6,7-dihydro-4H-thiazolo[2,3-cj[1 ,2,4]triazin-4-one, 3-Methyl-6,7-dihydro-4H-thiazolo[2,3-c] ,2,4]triazin-4-one and 3-Carbomethoxymethyl-6,7-dihydro-4H-thiazolo[2 3-c] [1 ,2,4]triazin-4-one.

67. A method as claimed in claim 63, wherein the treatment is carried out with a preparation as claimed in any one of claims 53 to 62.

68. A method as claimed in any one of claims 63 to 67, wherein a single compound of the general formula I is used for the treatment in an amount within the range of from 0.1 to 5 kg per hectare.

69. A method as claimed in any one of claims 63 to 67, wherein two or more compounds of the general formula I are used for the treatment in a total amount within the range of from 0.1 to 5 kg per hectare.

70. A method as claimed in claim 63, conducted substantially as described in any one of Examples 1 7 to 1 9 herein.

71. A method of protecting an area of land against weeds and/or regulating the growth of living plants in the area, wherein the area is treated with at least one compound selected from compounds of the general formula I given in claim 53, in which RX, R2, R3, R4 and n have the meanings given in claim 53.

72. A method as claimed in claim 71, wherein R" R2, R3, R4 and n have the meanings given in claim 54.

73. A method as claimed in claim 71, wherein the treatment is carried out with the compound claimed in any one of claims 3 to 52.

74. A method as claimed in claim 71, wherein the treatment is carried out with at least one compound selected from 3-Phenyl-6,7-dihydro-4H-thiazolo[2,3-cj[1 ,2,4]triazin-4-one, 3-Methyl-6,7-dihydro-4H-thiazolo[2,3-c][1 ,2,4]triazin-4-one and 3-Carbomethoxymethyl-6,7-dihydro-4H-thiazolo[2,3-c][1,2,4]triazin-4-one.

75. A method as claimed in claim 71, wherein the treatment is carried out with a preparation as claimed in any one of claims 53 to 62.

76. A method as claimed in any one of claims 71 to 75, wherein a single compound of the general formula I is used for the treatment in an amount within the range of from 0.1 to 5 kg per hectare.

77. A method as claimed in any one of claims 71 to 75, wherein two or more compounds of the general formula I are used for the treatment in a total amount within the range of from 0.1 to 5 kg per hectare.

78. A method as claimed in any one of claims 71 to 77, wherein the area of land is a crop area.

79. A method as claimed in claim 78, wherein the crop is selected from soya bean, potato, cotton, maize and wheat crops.

80. A pack which comprises at least one compound selected from compounds as claimed in claim 1, together with instructions for its use as a herbicide and/or for regulating the growth of a living plant.

81. A pack which comprises at least one compound selected from compounds as claimed in claim 2, together with instructions for its use as a herbicide and/or for regulating the growth of a living plant.

82. A pack which comprises the compound claimed in any one of claims 3 to 52, together with instructions for its use as a herbicide and/or for regulating the growth of a living plant.

83. A process for the manufacture of a compound of the general formula I given in claim 1, in which R1, R2, R3, R4 and n have the meanings given in claim 1, wherein a) a compound of the general formula II

in which R, has the meaning given above, is reacted (i) with a compound of the general formula Ill

in which R2, R3, R4 and n have the meanings given above and Hal represents a halogen atom, in the presence of a base, or (ii) with a compound of the general formula IV

in which R2, R3, R4, n and Hal have the meanings given above, or (iii) when n represents 1 and there is a single carbon-to-carbon bond in each of the 6,7- and 7,8positions, with a compound of the general formula V

in which R2, R3, R4 and Hal have the meanings given above, and, if desired, any resulting isomers are separated by column chromatography, or b) a compound of the general formula VI

in which R1 has the meaning given above and R represents a hydrogen atom or a C1-C4-alkyl group, is reacted with a compound of the general formula VII

in which R2, R3, R4 and n have the meanings given above, or c) a compound of the general formula VI

in which R1 and R have the meanings given above, is reacted with thiosemicarbazide of the formula H2N-NH-CS-NH2 to form a compound of the general formula VIII

in which R1 and R have the meanings given above, this compound of the general formula VIII is then reacted either with a compound of the general formula III

in which R2, R3, R4, n and Hal have the meanings given above, in the presence of a base, or with a compound of the general formula IV

in which R2, R3, R4, n and Hal have the meanings given above, to form a compound of the general formula IX

in which R1, R2, R3, R4, n and R have the meanings given above, and this compound of the general formula IX is cyclised in the presence of a basic catalyst, or d) when R1 represents a group of the formula -CH2COOF', R' representing a hydrogen atom or a C1-C4-alkyl group, a compound of the general formula X R'OOC--C#C-COOR' (X), in which R' has the meaning given above, is reacted with a compound of the general formula VII

in which R2, R3, R4 and n have the meanings given above, to form a compound of the general formula Xl

in which R2, R3, R4, n and R' have the meanings given above, this compound of the general formula XI is cyclised in the presence of a base to form a compound of the general formula Xli

in which R2, R3, R4, n and R' have the meanings given above, and this compound of the general formula XII is isomerised.

84. A process as claimed in claim 83, conducted substantially as described herein.

85. A process as claimed in claim 83, conducted substantially as described in any one of Examples 1 to ii herein.