DE2735457A1 - BENZOIC ACID DERIVATIVES - Google Patents

Description

Patent attorney « U -

Or. Franz Lederer "* ⁵ · Aug. 1977 DipMng. Reiner F. Mey "

8000 Munich 80

RAN 6102/19

F. Hoffmann-La Roche & Co. Aktiengesellschaft, Basel / Switzerland

Benzoic acid derivatives

The present invention relates to agents for regulating plant growth and agents for controlling weeds. the The invention also relates to a method for producing such agents and a method for regulating plant growth and weed control using such means.

The present invention relates to an agent for regulating plant growth and for weed control, which thereby is characterized in that there is an effective amount of a compound of the general formula

-1 ~ 3

COOH

(D

Hof / 4.7.1977 7098RR / 1004

* 2 7 3 b A 5 7

where R is hydrogen, lower alkyl with 1-6 carbon atoms, lower alkanoyl, where the alkanoyl group can be substituted with a carboxyl group or with one or two halogen atoms, or a benzoyl group which can additionally carry one or two substituents, these substituents being halogen, Nitro, amino, lower alkyl or lower alkoxy with 1-3 carbon atoms, R is lower) alkyl or lower alkoxy with 1-3 carbon atoms and R is hydrogen or lower alkyl with 1-6 carbon atoms,

2
with the proviso that R is a lower alkyl

group with 2 or 3 carbon atoms or j represents a lower alkoxy group of 1-3 carbon atoms when R and R each Mean hydrogen,

or salts of such compounds, and contains inert carrier material.

Preferred plant growth regulators and weed killers Agents according to the present invention contain one

2
Compound of formula I wherein R is a lower alkyl group with

1-3 carbon atoms or a salt of these compounds > 5 fertilize. Such plant growth is also regulative active and weedkillers preferred which contain a compound of the formula I, wherein R is hydrogen, a means lower alkyl group with 1-6 carbon atoms or a lower alkanoyl group, the carboxyl group with a or two halogen atoms may be substituted and R represents a hydrogen atom. Salts of such compounds are equally preferred.

The agents defined above are particularly useful as post-emergence and pre-emergence plant growth regulators as well as herbicides. However, the post-emergence growth-regulating effect predominates.

70988B / 10 (H.

27 3 b /. 57

According to the invention, the method for regulating plant growth and for combating weeds is characterized in that the plants whose growth you want to regulate with an effective amount of a compound of the Formula I or one of the above-mentioned plant growth regulators Agent or a weed control agent.

The term "plant growth regulator" like them is used here, denotes, for example, a connection that either the growth of main or secondary branches, or Sprouts of plants delayed or stimulated. Such a connection is capable of (delaying or stimulating) flower formation, the onset of flowering, the formation of shoots or twigs, the parthenocarpy, fruit and / or leaf fall and to influence fruit and / or leaf ripening. Furthermore, effects and influences on the transport of Substances within the plant, for example a stimulation of the latex flow and / or the metabolism or for example to understand an increase in sugar content within the plant, etc. The compounds stabilize the plants against drought and frost as well as against substances known as "air pollution" such as sulfur dioxide, ozone, etc. For example, causes in bush plants this regulating activity delays the growth in length while at the same time stimulating lateral growth. the 6-Amino-o-toluic acid is particularly active in stimulation of the latex flow.

The term "intact plant" denotes a normally growing plant as opposed to one that has been separated from the plant Part such as shoot pieces, coleoptiles or other isolated parts of plants.

The plant growth regulating and weed killing Agents according to the present invention are particularly useful for regulating plant growth. You own

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pre-emergence are plant growth regulating effects however, especially useful when used as post-emergence plant growth regulators be used.

These funds are particularly active in and against the following plants (especially young plants):

a) cereals such as grain, rice, wheat, rye, barley, oats, etc .;

b) Trees and bushes such as fruit trees such as apples, pears, peaches, cherries and citrus, as well as Cocoa, tea, coffee, bananas, gum, olives and nut trees;

c) Ornamental plants such as privet, home beech, white cedar, Juniper, Rose, Azalea, Chrysanthemum, Poinsettia, Cyclamen, Pyracantha, Forsythia, Magnolia, Petunia and Bromeliads;

d) crops such as cotton, soybeans, peanuts, tobacco, flax, sugar beet and pineapple;

e) Vegetables such as Solanaceae (for example tomatoes), legumes, pumpkins, melons, cucumbers, etc .;

f) berries such as strawberries, blueberries, raspberries, blueberries, blackberries and currants; and

g) grasses. 30th

The means for regulating plant growth and for combating weeds are thereby achieved according to the invention prepared by mixing an effective amount of a compound of formula I with inert carrier material. 35

In order to ensure an even distribution of the active compound in the growth regulating agents and the weed

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to achieve control agents, the combination with conventional auxiliaries customary for growth regulators, Modifiers, diluents or conditioning agents mixed and then to form solutions, emulsions, emulsifiable concentrates, dispersions, dusts, granules or formulated wettable powders. Plant growth regulators Agents and herbicides in the form of liquid formulations for direct spraying can, for example as aqueous solutions - wherever possible - or as solutions in solvent mixtures (such as acetone, methanol, Dimethylformamide in the ratio 90: 8: 2, [volume / volume]) can be produced. Emulsifiable concentrates that are 5-50% or more of active ingredient, depending on its solubility, can be prepared in suitable solvents, for example in n-methylpyrrolidine, dimethylformamide, Cyclohexanone, etc. Surfactants such as wetting agents, dispersants, emulsifiers, etc. are used in added in sufficient amount to achieve the desired formulation characteristics.

Typical ways in which the plant growth and weed control agents according to the present invention can be formulated are:

a) aqueous concentrates containing 10-50% (percent by weight) contain the active ingredient;

b) ready-to-spray solutions which contain 0.0001-10% (percent by weight) of the active ingredient;

c) water-soluble powders containing 10-90% (percent by weight) of active ingredient;

d) Sprayable powders which contain 35-65% (percent by weight) of the active ingredient;

e) dusts or granules which contain 2-10% (percent by weight) of active ingredient;

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27 3SA57

f) Homogeneous, pourable preparation that is dispersible in water to form ready-to-use spray liquors, and the Contains 10-40% (weight percent) of active substance.

Different types of application can better suit the numerous purposes for which the connections are made

of the formula I can be used, adapted if you use compounds which improve dispersion, adhesion, resistance to rain and penetration, such as Fatty acids, waxes, resins, wetting agents, emulsifiers, mineral .0 or vegetable oils, binders, etc. In the same way leaves The biological spectrum of these agents by adding substances that have bactericidal, herbicidal, fungicidal properties have, greatly broadening, or by adding fertilizers, chelating agents, and / or other plant growth regulators clogs.

Examples of growth regulators, which the invention Agents that can be added are:

2,2-dichloropropionic acid,
N- (4-aminobenzenesulfonyl) methyl carbamate, 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine, 4-chloro-2-oxobenzothiazolin-3-yl-acetic acid, 5-bromo-6-methyl -3- (1-methyl-n-propyl) uracil, 3,5-dibromo-4-hydroxybenzonitrile, D, N-Ethy1-2- {phenylcarbamoyloxy) propionamide, N- (4-bromo-3-chlorophenyl) -N '-methoxy-N ¹ -methyl-urea, methyl-a-chloro ^ -hydroxyfluoren-o.-carboxylate, H ^l -4 - (^ - chlorophenoxy) -phenyl-N, N-cliRethylurea, isopropyl-N- (3 -chlorphenyl) carbamate, 2,3 # 5 »6-tetrachloroterephthalic acid dimethyl ester (DCPA), 2,4-dichlorophenoxy-acetic acid, ^ isopropylaynino-e-methylamino ^ -methylthio-10 ^ -triazine, n-butyl-9- hydroxyfluorene-9-carboxylate,

709886/1004

Ethylene,

Naphthoxy acetic acid,

3,6-dichloro-2-methoxybenzoic acid, (+) - 2- (2,4-dichlorophenoxy) propionic acid, ^ lO-Dihydro-eajlOa-diazoniaphenanthren- ^ A,

NM3 # * - dichlorophenyl) -N, N-dimethylurea, Obberellic acid, Indolylesslic acid, Indoly! Butyric acid,. '

% -Hydroxy-3 * 5-di-iodobenzonitrile,

H ¹ - (j5,4-dichlorophenyl) -N-methoxy-N-methyl urea,

4-ChloΓ-2-ynethylphenoxy-acetic acid, 4- (4-chloro-2-methylphenoxy) butyric acid, (+) - 2- (4-chloro-2-methylphenoxy) propionic acid,

N- (Benzothiazol-2-yl) -N, N ¹ -dimethylurea, M ^f - (5-chloro-4-ynethoxy phenyl) -N, N-dimethylurea,

1,2,3 * e-Tetrahydro-Jiö-dioxopyridazine,

N * - (4-chlorophenyl) -N-methoxy-N-methyl urine, H ^l - (4-chlorophenyl) -M, N-dimethylurea, Haphthylacetic acid, ' K-l-naphthylphthalamic acid,

2,4-dichlorophenyl-4-nitrophenyl ether, 1,1 • -Dimethyl ^, 4'-bipyridylium-2A, 5- (m-tolylcarbainoyloxy) phenylcarbamate, 4-amino-3 # 5 »6-trichlorpicolinsaur ⁱ e, 4,6-bis-IsopΓopylaInino-2-methylthio-l, 3,5-triazine,

H- (3 # 4-dichlorophenyl) propionamide,

70988R / 1004

27 3 ^ι ") Λ

Isopropyl-N-phenylcarbamate,
5-amino- ¹ -chloro-2-phenylpyridazin-3 (2H) -one, H-dimethylamino succinic acid, 2-chloroethyl phosphorous acid,

Tributyl ^^ - dichlorobenzyl-phosphonium chloride, 2,4,5-trichlorophenoxypropionic acid, 2 »3» 6-trichlorobenzoic acid,
2-chloro-4,6-bis-ethyl2unino-1,3 * 5-triazine, sodium chlorace did,
2,4,5-trichlorophenoxyacetic acid,

^ -Aethylamino-S-methylthio-o-t-butylamino-l ^ iS-triazine- (tertbutryn),

2,3,5-triiodobenzoic acid ,
l, l, 4-trimethyl-6-isopropyl-5-propionyl-indar ;,

Exemplary fungicides which the compounds according to the invention can be added are:

2 »4-dichloro-6- (o-chloroaniline) -S-triazine, 2,4,5,6-tetrachloroisophthalic acid nitrile, p-Dlmethylaminophenyldiazo-sodium sulfonate,

Manganese-ethylene-bis-dithiocarbainate, Zinc-ethylene-bis-dithiocarbaroate, coordination product of zinc and manganese-ethylene-bisdithlocarbamate,

Metnyl-1- (butylcarbamoyl) -2-benzimidazole-carbamate, 2- (4-thiazole) benzimidazole,

cis-N-l (triehlomethyl) thio] -4-cyclohexene-1,2-dicarboximide.

709886/1004

The application levels given below are based on the results presented here and are not such broadly described to include all possible cases as numerous factors influence the levels of use. For example, the amount can vary not only between different plant species, but also within of a certain species, for example depending on factors such as the plant size and the age of the plant, the season, the type of soil and the climatic conditions at the time of use, such as air temperature, light intensity, Rain and wind. Furthermore, when the compounds or the means are applied via soaking the soil higher concentrations necessary, since with this type of application the plant is treated indirectly compared to a direct treatment when the agent or compound is applied to leaves and stems, for example by spraying on the plant.

The amount of active ingredient in plant growth regulators Means varies accordingly depending on the plants to be controlled, the required application amount, the type of application, the active ingredient used and the level of control of plant growth that is sought will. In general, the agents are included in the ready-to-spray Form less than 50% active ingredient. For example, when applied in powder form, 35-65% (percent by weight) and at Application in liquid form up to 10% (percent by weight) of active ingredient is preferred.

Basically, the amount of active ingredient that is used is selected to provide effective control of plant growth is achieved. Accordingly, the selection of the minimum usage amount is determined by the Minimum amount of active ingredient which is able to bring about the lowest limit of the desired growth retardation. the The selection of the maximum amount to be used is determined accordingly by the amount of active ingredient that is the upper one

- ie--

Limit of the desired growth retardation. This means in the case of grasses that use for ornamental lawns find the amount that avoids a sparse appearance of the ornamental lawn, but on the other hand too fast Prevents lawn growth and unwanted chlorosis

(i.e. the lawn turning yellow). So is convenient an amount of active ingredient used in the control of the lawn that delays normal growth. rate of 40-60%. In the case of grass, a growth retardation below 40% is not considered sufficient, because manual treatment of the lawn cannot be eliminated. On the other hand, it exceeds the growth retardation with turf 60%, this must be viewed as too pronounced due to the aesthetic result.

L5 Another disadvantage of the excessive growth retardation of a lawn is that immigration is easier seen from weeds.

The amount of active ingredient that meets these criteria is determined from such aspects, for example on the tomato plant. In order to achieve the greatest wake-regulating effect, quantities of 0.5-10 kg or more per hectare of active ingredient are used. These amounts are based on the weight of the active compound. In the same way, the greatest trailing growth-regulating activity is generally obtained with amounts which are between 1 kg and 5 kg or more of active ingredient per hectare. A preferred dosage interval of the spray solutions is between 1-150 ¹ OOO ppm depending on the plant species to be treated. A particularly preferred dosage is generally between 100 and 10,000 ppm.

7 0 π P ¹ M- / 1 η 0 A

Another advantage of using an active ingredient of the formula I is the absence of any permanent effect the plants or a regulating effect that remains in the soil. The link is slowly breaking down and there is thus a consequent reduction in activity. This effect has advantages because

a) a short-term effect, which can be prolonged by subsequent further treatment, is achieved;

b) the normal growth conditions of the plant occur as the activity decreases;

c) no harmful residues remain either on the plant or in the soil.

The duration of the delay effect varies as a function numerous factors such as the type of plant treated, climatic conditions, etc.

Although the compounds of formula I and their salts regulate plant growth If they have activity, they are practically non-toxic to animals. However, there are weeds that if they do treated as described above die off. Such weeds are shown in Examples 2 below and 7. Further examples of weeds that can be eradicated with the agent according to the invention are for example, Sorghum halepense, Imperata cylindrica, Panikum spp. and Paspalum spp.

The following examples illustrate the various formulations of the plant growth regulating agents Agents and the weedkillers according to the present invention.

709886/1004

A. Aqueous formulations

The amphoteric character of the active ingredients allows the formation of more or less water-soluble substances Salts by reaction with bases or acids.

a) With bases

A typical formulation is:

Compound of formula I 2OO g

Diethanolamine 150 g

Water, deionized to ¹ 000 ml

Instead of diethanolamine, other organic ones can be used Bases such as dimethylamine, triethanolamine, aminomethylpropanol, Morpholine, etc. can be used, the concentrations of active ingredient in the formulation depending on the solubility depends on the salts. Such formulations can be mixed with surfactants and thus the wetting power of their aqueous, ready-to-use Dilution, and thus usually also its effect, can be improved. The application concentrations of the active ingredient range between 0.01 and 1% (percent by weight) preferably between 0.05 and 0.8% (weight percent), the A wetting agent is usually removed from the spray mixture. Below such formulations, which are suitable for dilution, are given:

1. Formulation for an application concentration that contains 0.84 active ingredient:

Compound of the formula I 2OO g

Surfactant 6.25 g

Diethanolamine 150 g

Water, deionized to ¹ 000 ml

709886/10 (U

2. Formulations for an application concentration containing 0.05% active ingredient:

Compound of the formula I 2OO g

Surfactant 100 g

Diethanolamine 150 g

Water, deionized to ¹ 000 ml

The surfactant can be an anionic surfactant such as alkali salts of alkyl sulfates (e.g. Sodium lauryl sulfate), alkali salts of alkylarylsulfonic acids (e.g. sodium dodecylbenzenesulfonate). Furthermore can the surfactants be nonionic surfactants, such as ethylene oxide condensation products of alkylphenols such as for example nonylphenol with 8-10 moles of ethylene oxide or fatty alcohols such as stearyl alcohol with 8-10 moles Ethylene oxide.

b) with acids

Salts can be prepared from the compounds of the formula I with acids, the acids being, for example, hydrochloric acid, Sulfuric acid, phosphoric acid or acetic acid come into question. The salts formed with hydrochloric acid are the most soluble Salts and are therefore preferred. Typical formulations can be made with the following ingredients:

1. Compound of the formula I hydrochloric acid (32%)

Water, deionized ad

2. Compound of formula I surfactant

hydrochloric acid

Water, deionized ad

A solution is thus obtained which contains 0.8% of active ingredient.

70988B / 1004

100 G G 151 G G 1 ¹ OOO ml G 100 ml 6th , 25 151 1 • ooo

3. Compound of Formula I.

Surfactant

hydrochloric acid

Water, deionized

ad

1OO g
1OO g
151 g
I ¹ 000 ml

After dilution, a solution is obtained that contains 0.05% Contains active ingredient. The surfactant can be nonionic as above - or be cationic, for example, alkylbenzylammonium compounds such as dodecyldimethylbenzy1-ammonium chloride.

B. Powdered water-soluble formulations taking advantage of salt formation

Two typical formulations, one formulation containing a base and the other formulation containing an acid, are described below:

Compound of Formula I 20.0

Soda, calcined 15.5

Sodium Lauryl Sulphate (surfactant) 1.0

Lactose 63.5 sulfamic acid
Ethylene oxide-propylene oxide *

20.0

66.0

13.0

1.0

[* solid block polymer (80% polyethylene glycol ether chains) (non-ionic surfactant)]

These formulations are made by mixing and finely grinding the formulation components. You get free-flowing, wettable with water and clearly dissolving Powder.

709BHR / 1004

2735

C. Fixed formulations

1. Wettable powder (wettable powder)

Compound of the formula I 50, O g

hydrated silica 5, og

Sodium lauryl sulfate (surfactant) 1.0 g

Sodium lignosulfonate (dispersant) 2.0 g

Kaolin B 24 42, O g

The formulation components are mixed and finely ground. Free-flowing powders which can be wetted with water and have good suspension properties are obtained.

2. Dusts

After mixing and grinding, the formulation components result a powder that can be easily dusted.

Compound of the formula I 5, Og

Talk 95, O g

3. Granules

Compound of the formula I 5 # ü g

Polyethylene glycol 4PEG SOO) 2.0 g

Calcium carbonate granulated 1 mm 93.0 g

The calcium carbonate grains become evenly with the Polyethylene glycol sprayed and then mixed with finely ground active ingredient. The polyethylene glycol works

as an adhesive and binds the active substance to the carrier grain.

70988S / 1004

273S457

D. Other formulations

1. The following formulation components are mixed and ground in a ball mill until the particle size of the active ingredient is 1-5 microns.

Compound of the formula I 250g

Sodium salt of a sulfonated naphthalene-formaldehyde condensation product 25 g

Bentonite 15 g

Water, deionized to ¹ 000 ml

A homogeneous, pourable preparation is obtained which can be dispersed in water to form ready-to-use spray liquors.

2. Emulsifiable concentrate

Compound of formula 1 100 g

Emulsifier (mixture of one

Condensation product of nonylphenol with 8-10 moles of ethylene oxide and the calcium salt of dodecylbenzenesulfonic acid) 100 g

Cyclohexanone ad ¹ 000 ml

The active substance and emulsifier are dissolved in cyclohexanone and result in a clear solution which emulsifies spontaneously in water, and later even solubilizes.

3. Ready-to-use solutions

Compound of formula I 2.0 g

Acetone 97.9 g

Tensiofix AS iTensid) O, l g

(Tensiofix AS is a mixture consisting of non-ionic activeii AlkyIphenol derivatives, polyethylene oxide alkylphenol condensation product and anion-active dodecylbenzene

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sulfonate; the mixture also contains unspecified small amounts of n-butanol and carbon tetrachloride). The formulation is normally diluted directly before application and a concentration of active ingredient is obtained from 0.1-0.2% (percent by weight), the dilution being carried out with water and Tween 20.

The following examples show the particular advantage of the plant growth regulators according to the invention Middle. These advantages consist in a pre-emergence and post-emergence plant growth-regulating effect, which agents can be used on numerous plants. To underline the plant growth regulating and herbicidal activity of the agents according to the invention, in the following examples show the results of experiments in greenhouses.

The present invention also relates to the new compounds of the formula I and their salts, i. Compounds of the general formula

'3

COOH

(Ia)

where R is hydrogen, lower alkyl with 1-6 carbon atoms, lower alkanoyl, where the alkanoyl group with a carboxyl group or one or two halogen atoms can be substituted, or a benzoyl group, which also has one or two May carry substituents, these substituents halogen, nitro, amino, lower alkyl or lower alkoxy with 1-3 carbon atoms, R a lower alkyl

7 0 9 Π P, Γ. / 1 0 0 //

or lower alkoxy group of 1-3 carbon atoms and R represents a hydrogen atom or an alkyl group of 1-6 carbon atoms, with the proviso that R represents a lower alkyl group of 3 carbon atoms or a lower alkoxy group of 2 or 3 carbon atoms when R and R each represent Denote hydrogen or that R denotes a lower alkyl group with 1-3 carbon atoms or a lower alkoxy group with 2 or 3 carbon atoms, when R denotes the acetyl group and R denotes a hydrogen atom,
and salts of these compounds.

Examples of lower alkanoyl groups are formyl, acetyl, propionyl, butyryl, isobutyryl, valeroyl and hexanoyl etc. groups. The lower alkanoyl groups may be substituted with a carboxyl group, such as in the case a succinyl group or with one or two halogen atoms, as for example in the case of a chloroacetyl or dichloroacetyl group. Examples of a benzoyl group which carries one or two substituents, these substituents being halogen, Nitro, amino or lower alkoxy with 1-3 carbon atoms are 2-methyl-6-nitrobenzoyl and 2-amino-6-methylbenzoyl. The lower alkyl and lower alkoxy groups can also be straight-chain and branched, for example Methyl, ethyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, etc.

A preferred group of compounds of the formula Ia are those in which R is a lower alkyl group with 1-3 carbons represents atoms of matter. Further preferred compounds of the

Formula Ia are those in which R is hydrogen, lower alkyl having 1-6 carbon atoms or lower alkanoyl, where the lower alkanoyl group can be substituted with a carboxyl group or with one or two halogen atoms and R means a hydrogen atom.

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Examples of preferred compounds of the formula Ia and their salts are:

6-methylamino-o-toluic acid, 6-formamido-o-toluic acid, 6-acetamido-o-toluic acid, 6-propionamido-o-toluic acid, 6-butyramido-o-toluic acid, 6-isobutyramido-o-toluic acid, 6-hexanamido-o-toluic acid, 6- (2-chloroacetamido) -o-toluic acid, Ammonium salt of 2'-carboxy-3'-methylsuccinic anilide, Ammonium salt of 6-formamido-o-toluic acid, N-acetyl-6-ethy-anthranilic acid, 6-benzamido-o-toluic acid, 6- (6-nitro-o-toluylamido) -o-toluic acid, 6- (6-Amino-o-toluylamido) -o-toluic acid, 6- (n-propyl) -anthranilic acid, 6-isopropyl-anthranilic acid and 6-Diniethylainino-o-toluic acid.

In a further embodiment, the present invention relates to a process for the preparation of the new compounds of the formula Ia and their salts. The inventive The method is characterized in that one

a) the nitro group in a compound of the general formula

(U)

wherein R has the meaning given above,

reduced, or

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b) for the preparation of a compound of the formula Ia, wherein R is a lower alkyl group having 1-6 carbon atoms and R Is hydrogen, a corresponding compound of the formula Ia in which R and R are hydrogen, correspondingly monoalkylated or

c) for the preparation of a compound of the formula Ia, wherein

R and R each represent a lower alkyl group with 1-6 carbon atoms, a corresponding compound of the formula Ia, where R is hydrogen or a lower alkyl group with 1-6 carbon atoms and R is hydrogen, reductively alkylated, or

d) for the preparation of a compound of the formula Ia in which R is a lower alkanoyl group which is linked to a carboxyl group or one or two halogen atoms or a benzoyl group, the benzoyl group being one or can carry two substituents and the substituents can be halogen, nitro and lower alkoxy with 1-3 carbon atoms, a corresponding compound of the formula Ia in which R is a hydrogen atom is acylated accordingly, or

e) for the preparation of a compound of the formula Ia in which R

is a benzoyl group which carries one or two amino substituents, a compound of the formula Ia in which R is a benzoyl group with one or two nitro substituents, reduced, or

f) for the preparation of a compound of the formula Ia in which R and R are each hydrogen, a compound of general formula

Uli)

wherein R has the meaning given above,

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TA

oxidized, and if necessary a compound obtained from the Formula Ia converted into a salt.

According to embodiment a) of that described above In the process, a nitro compound of the formula II is reduced by catalytic hydrogenation. Suitable catalysts that can be used are noble metal catalysts such as platinum, palladium, rhodium and also Raney nickel. The catalysts can be deposited on a conventional support material. The catalytic hydrogenation can in the presence of a suitable inert organic solvent, especially in the presence of a lower alkanol such as for example, methanol, ethanol, etc. can be carried out. Temperature and pressure are not critical parameters of the reaction, although it is preferred to conduct the catalytic hydrogenation at about room temperature and atmospheric pressure.

According to embodiment b) of the production process, a compound of the formula Ia in which R and R are hydrogen mean, correspondingly monoalkylated and a compound of the formula Ia is obtained in which R is a lower alkyl group with 1-6 carbon atoms and R represents a hydrogen atom. This monoalkylation can be known per se Way can be carried out by adding an appropriate alkyl halide, in particular an alkyl iodide such as methyl iodide or a suitable dialkyl sulfate such as dimethyl sulfate is used.

According to embodiment c) of the preparation process, a compound of the formula Ia in which R is hydrogen or a lower alkyl group having 1-6 carbon atoms and R is a hydrogen atom is reductively alkylated. This reductive alkylation is carried out in a manner known per se by converting a suitable aldehyde (for example formaldehyde) in the presence of a suitable acid (for example formic acid) with hydrogen in the presence of a suitable hydrogenation catalyst (for example a palladium catalyst such as palladium

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Treated on activated carbon. Thus, if a compound of the formula Ia in which R and R are each hydrogen is obtained reductively is alkylated, a compound of the formula Ia in which R and R are an identical lower alkyl group having 1-6 carbon atoms and R is hydrogen. On the other hand, if a compound of the formula Ia in which R is a lower alkyl group with 1-6 carbon atoms and R is hydrogen as a starting material is used for the reductive alkylation, depending on the aldehyde used and that in the starting material ) alkyl group represented by the symbol R, a compound of the formula Ia in which the represented by the symbols R and R. Alkyl groups identical or different alkyl groups could be. In a preferred embodiment arrives a compound of the formula Ia as starting material for use, wherein R and R are hydrogen, which in turn are in situ was formed from a compound of formula II under the conditions of reductive alkylation.

The acylation of a compound of formula Ia wherein R

> 0 represents hydrogen, takes place according to the embodiment

d) the manufacturing process by using a suitable acid halide, for example acetyl chloride, succinic acid dichloride, Benzoyl chloride, 2-methyl-6-nitrobenzoyl chloride, etc. or a suitable acid anhydride, such as acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, Hexanecarboxylic anhydride, chloroessiqic anhydride, etc. are used. This acylation is in the presence of an inert organic solvent such as an aromatic hydrocarbon such as benzene, toluene, etc. is accomplished. Preferred is this acylation in the presence of an acid binding agent such as an inorganic base such as a Alkali metal hydroxide such as sodium or potassium hydroxide, or an organic base such as a tertiary one organic base such as triethylamine or pyridine. The temperature at which this acylation is accomplished is not critical. In general, the acylation is carried out at a temperature between about 20 ° C and the boiling point of the Reaction mixture carried out.

709886/1004

According to embodiment e) of the method according to the invention a compound of the formula Ia, in which R is a benzoyl group which bears one or more nitro substituents, catalytically hydrogenated by proceeding in a manner similar to that described above for the reduction of a nitro compound of formula II is described.

The oxidation of an isatin of the formula III is carried out according to Embodiment f) of the method according to the invention in a known manner Way done. In a preferred embodiment, the oxidation is carried out by treatment with hydrogen peroxide under alkaline conditions (for example in an aqueous alkali metal hydroxide solution, such as in a aqueous sodium hydroxide solution or in an aqueous potassium hydroxide solution, but preferably carried out in aqueous sodium hydroxide). Mxt benefit will be at a temperature above Room temperature (for example at about 8O) and worked under normal pressure.

The nitro compounds of the formula II which are used as starting material in process aspect a) are either known or can be prepared in a manner known per se. The same applies to the compounds of formula III, the in process aspect f) serve as starting material; these compounds are also known or can be found in produce themselves in a known manner.

The compounds of the formula I or the formula Ia form Salts with bases such as, for example, with alkali metal hydroxides (such as sodium hydroxide and potassium hydroxide), with alkaline earth metal hydroxides (e.g. calcium hydroxide) and with organic bases (e.g. ammonia, diethanolamine, Triethanolamine, uimethylamine, aminomethylpropanol, Morphoiin, etc.). The preliminary bindings according to the invention, in which K is a hydrogen atom or an alkyl group with 1-6 Represents carbon atoms, form KaI ^ e with organic Acids (e.g. acetic acid, tartaric acid,

709886/1004

Citric acid, methanesulfonic acid, p-toluenesulfonic acid, etc.) and with inorganic acids (such as hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, etc.).

The following examples illustrate the invention. All temperatures are given in degrees Celsius.

709R8B / 10OA

- W-

example 1

In order to show the growth retarding effect in percent based on untreated plants, barley and blue grass are used and vines with a solution containing 0.4% 6-acetamido-o-toluic acid, Contains 49.5% acetone, 0.1% Tensiofix AS and 50% water, treated. This concentration of 6-amino-o-toluic acid corresponds to an amount of approximately 4 kg per hectare. The results are summarized in Table I below.

Table I.

Test plants Percent growth lag
based on untreated
Controls Barley (Hordeum distichon)
Blue grass (Poa pratensis)
Vines (vitis vinifera) 25th
50
25th

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Example 2

The post-emergence herbicidal effect of 6-ethyl-anthranilic acid can be achieved by spraying Digitaria sanguinalis in the 3-leaf stage with a spray liquid in a volume of l'OOO 1 per hectare contains 5 kg of active ingredient (per hectare). 3 weeks after the treatment, the plants are examined and it is found that there is an 80% kill of them Plants has occurred.

The compounds of formula I can be different in portions Big ones in packs or containers suitable for agrochemical purposes go on sale. These Packs or containers can be made of paper, plastic, glass or metal. The compounds of formula I, those in these packs or containers can be used to regulate the growth of plants or as herbicides be used.

In a preferred embodiment, the agents contain for regulating plant growth or for weed killing an effective amount of a compound of formula I together with at least one inert carrier material, its Molecular weight is 200 or more.

70988B / 100A

Example 3

4.53 g of 6-methylanthranilic acid are in a solution of 1.64 g of anhydrous sodium carbonate suspended in 6O ml of water, 3.78 g of dimethyl sulfate are added to this solution and the mixture is shaken at room temperature for 2 1/2 hours. the The solution is then cooled to 0, left to stand at this temperature for 1 hour and then the precipitate becomes filtered off. 1.75 g of a white powder are obtained. The filtrate is reduced to a small volume in a rotary evaporator reduced, cooled to 0 and the precipitated white powder (2.61 g) filtered off. The white powder obtained in this way becomes combined and recrystallized from ether. 2.5O g of a white solid mass are obtained. This white solid mass is through Chromatography on 180 g of silica gel purified by adding petroleum ether (Boiling point 40 - 60 ° C) ether, glacial acetic acid (297: 99: 4) as Eluent used. After evaporation of the eluate, 1.48 g of a white solid mass are obtained, which recrystallizes from ether 1.41 g of 6-methylamino-o-toluic acid as a white solid Provides substance with a melting point of 129.5-130 ° C.

Example 4

To 4.53 g of 6-methylanthranilic acid dissolved in 100 ml of hot Benzene, 5.3 ml of chloroacetic anhydride are added to 10 ml of benzene. The mixture is stirred for a short time and the precipitated product is filtered off Product. After recrystallization twice from benzene, 2.6 g of 6- (2-chloroacetamido) -o-toluic acid are obtained in

Form of white crystals that melt at around 140 ° C.

Example 5

The working procedure given in Example 4 is repeated; only 3.16 g of acetic anhydride are used instead of the chloroacetic anhydride. After recrystallization from Ethanol, 3.3 g of 6-acetamido-o-toluic acid are obtained with a Melting point of 176-180 °.

709836 / 10Oi

Example 6

The working procedure given in example 4 is repeated, by using 4.75 g of isobutyric anhydride in place of the chloroic acid anhydride. After two recrystallizations 2.9 g of 6-isobutyramido-otoluic acid are obtained from ethyl acetate / hexane with a melting point of 163-165 °.

Example 7

2O, 72 g of the potassium salt of 6-methylanthranilic acid are in 2OO ml of benzene and 1O, 2 g of triethylamine suspended. 15.5 g of succinic acid dichloride are added dropwise to the suspension, whereupon a black precipitate forms. That

The mixture is stirred for 2 hours at 60 °, cooled and filtered, and the solid residue is washed well with water. The filtrate will acidified, the benzene layer separated and the aqueous phase extracted twice with ethyl acetate. The organic phases are combined and evaporated. The oily residue is taken up in 50 ml of ethanol and treated with aqueous ammonia. The solvent is evaporated and the residue is dried. The ammonium salt of 2'-carboxy-3'-methysuccinic acid is obtained in the form of a hygroscopic solid substance.

Example 8

To 9.6 g of 6-methylanthranilic acid dissolved in 3OO ml of 2N sodium hydroxide, 7 ml of benzoyl chloride and Given 30 ml of 2 N sodium hydroxide solution. Diatomaceous earth is then added to the mixture and then filtered. The filtrate is with 12 ml of 5 N hydrochloric acid acidified and the precipitate filtered off. Recrystallization from ethyl acetate / hexane yields 7.2 g 6-Benzamido-o-toluic acid in the form of white crystals, which at 161 - 162 melt.

Example 9

To 3O g of 6-methyl-anthranilic acid, dissolved in 500 ml of 88% strength Formic acid, 166 ml of acetic anhydride are added at 60 °. The mixture is stirred for 1 hour without heating and then evaporated to dryness. The residue is recrystallized from ethyl acetate / hexane and 13 g of 6-formamido-toluic acid are obtained with a melting point of 144 - 145 ° C.

Example 10

2.3 g of 6-formamido-o-toluic acid are dissolved in 20 ml of acetone and mixed with 5 ml of concentrated aqueous ammonia solution offset. The mixture is then evaporated to dryness. The residue is washed with ether and dried. You get 2 g of the ammonium salt of 6-formamido-o-toluic acid in the form of white crystals with a melting point of 148-152 °.

Example 11

4.70 g of 6-ethylanthranilic acid and 2.94 g of acetic anhydride are added to a solution of 1.38 g of sodium hydroxide in 35 ml of water added. The mixture is shaken vigorously for 5 minutes and then acidified with concentrated hydrochloric acid. The precipitated product is filtered off and recrystallized from a hot mixture of ethanol and water. You get 3.96 g of N-acetyl-6-ethy! Anthranilic acid in the form of cream-colored Crystals that melt at 144 °.

Example 12

4.67 g of 6-methyl-anthranilic acid and 4.07 g of propionic anhydride are added to a solution of 1.51 g of sodium hydroxide in 38 ml of water added. The mixture is shaken vigorously for 5 minutes and then acidified with concentrated hydrochloric acid. The white precipitate is filtered off and recrystallized from a hot mixture of ethanol and water. You get

709886/1004

5.07 g of 6-propionamido-o-toluic acid in the form of cream-colored Crystals that melt at 156-157 °.

Example 13

4.0 g of 6-methyl-anthranilic acid and 4.27 g of butyric anhydride are added to a solution of 1.29 g of sodium hydroxide in 32 ml of water given. The mixture is shaken vigorously for 5 minutes and then acidified with concentrated hydrochloric acid. The precipitate is filtered off and recrystallized from a hot mixture of ethanol and water. 4.4 g of 6-butyramido-o-toluic acid are obtained in the form of cream-colored crystals that melt at 129 °.

Example 14

5.0 g of 6-methylanthranilic acid and 7.13 g of hexanecarboxylic anhydride are added to a solution of 1.61 g of sodium hydroxide in 40 ml of water given. The mixture is shaken vigorously for 10 minutes and then with concentrated hydrochloric acid acidified and the solution extracted twice with chloroform. The combined organic phases are evaporated and the The oily residue is recrystallized from petroleum ether (boiling range 40-60 °). 1.80 g of 6-hexanamido-o-toluic acid are obtained in the form of cream-colored crystals that melt at 93.5 - 94.5 °.

Example 15

6.2 g of 2-methyl-6-nitrobenzoyl chloride are added to a solution of 10.38 g of methyl 2-amino-6-methylbenzoate in 12.5 ml of benzene. The mixture is stirred for 25 minutes at 20 °, then for a further 15 minutes at 50 ° and then filtered. 3.13 g of ^ -amino-e-methylbenzoic acid methyl ester hydrochloride are obtained. The filtrate is washed three times with 50 ml of 2N sodium hydroxide solution each time, then three times with 50 ml of 2N hydrochloric acid each time and again three times with 50 ml of water each time. The filtrate is then dried and evaporated. You get

709886/1004

6.58 g of a brown gum. This brown gum is chromatographed on a column containing 435 g of silica gel, whereby petroleum ether (boiling range 40 - 60 °) / ether (1: 2) is used as eluent. The eluate is evaporated and obtained 3.43 g of 6- (6-nitro-o-toluamido) -o-toluic acid methyl ester in the form of a colorless gum.

0.52 g of sodium hydroxide are added to a solution of 2.87 g of 6- (6-nitro-o-toluamido) -o-toluic acid methyl ester in one Added a mixture of 9O ml of ethanol and 25 ml of water. The mixture is refluxed for 100 minutes, then cooled, diluted with water and extracted three times with 125 ml of ether each time. The organic extracts are discarded. the aqueous solution is acidified with 2N hydrochloric acid and extracted twice with 125 ml of ether each time. The combined ether extracts are washed three times with 125 ml of water each time, dried and evaporated. 2.46 g of 6- (6-nitro-otoluamido-o-toluic acid are obtained in the form of white crystals, which at

Melting 212 °.

Example 16

0.2O g of platinum oxide become a solution of 2.46 g of 6- (6-nitro-o-toluamido) -o-toluic acid given in 2OO ml of methanol. The mixture is shaken under pressure of one atmosphere of hydrogen until hydrogen uptake comes to a standstill (20 minutes). The mixture is then filtered and the filtrate is evaporated. There remain 2.32 g of a pale yellow gum. This gum is chromatographed on a column filled with 245 g of silica gel, a mixture of 2673 ml petroleum ether (boiling range 4O 6O °), 891 ml of ether and 36 ml of glacial acetic acid are used as eluents. The column will then continue with a mixture of 1366 ml petroleum ether (boiling range 40 60 °), 1366 ml of ether and 28 ml of glacial acetic acid eluted. The eluates are combined and evaporated. 1.37 g of 6- (6-amino-o-toluamido) -o-toluic acid are obtained in the form of white crystals,

709886/1004

which melt at 162.5 - 163.5 °.

Example 17

2.80 g of 4- (n-propyl) -isatin are in a solution of Dissolved 22.2 g of sodium hydroxide and 220 ml of water, and the The solution is then mixed with 100 ml of a 10% hydrogen peroxide solution over a period of 15 minutes at 60 ° offset. The mixture is stirred for a further 2 1/2 hours at 80 ° and then cooled to room temperature. After acidification with concentrated hydrochloric acid up to a pH of 3.6, a brown solid mass precipitates, which is filtered off, dried and from ether / petroleum ether (boiling range 40 - 60 °) is crystallized. 0.50 g of 6- (n-propyl) anthranilic acid is obtained in the form white crystals, with a melting point of 124 - 125 °.

Example 18

2, OO g of 4-isopropyl-isatin are in a solution of 19.0 g of sodium hydroxide are dissolved in 190 ml of water and the solution is stirred at 60 and over a period of 15 Minutes with 50 ml of a 10% hydrogen peroxide solution offset. The mixture is stirred at 80 ° for a further 30 minutes, then mixed with activated charcoal and stirred again for another 10 minutes. The mixture is then filtered off and the filtrate is collected Cooled to room temperature and acidified with concentrated hydrochloric acid to a pH of 3.6. The suspension obtained is extracted twice with dichloromethane and the combined organic extracts are evaporated. 0.51 g is obtained 6-isopropyl anthranilic acid in the form of white crystals, with a melting point of 135 - 136 ° C.

Example 19

4.0 g of palladium on activated charcoal (5%) are added to a solution of 6.0 g of 6-nitro-o-toluic acid in a mixture of 400 ml of formic acid and 33 ml of 40% formalin were added. That

709886/1004

«3

1 mixture is shaken under 1 atmosphere of hydrogen until the hydrogen uptake ceases (4 hours). The mixture is then filtered and the filtrate evaporated. You get 5.22 g of a pale yellow gum which is dissolved in 400 ml of methanol

5 is solved. The solution obtained is cooled to -2O ° and filtered to separate insoluble by-products. The filtrate is concentrated in vacuo to a volume of 50 ml and cooled to -20 °. 1.23 g of 6-dimethylamino-otoluic acid are obtained in the form of white crystals with a melting point

10 from 107 -111 °.

709886/1004

Claims (1)

Claims 1. Means for regulating plant growth and for Weedkiller, characterized in that it contains an effective amount of a compound of the general formula . COOH (D I I 1 wherein R is hydrogen, lower alkyl with 1-6 carbon atoms, lower alkanoyl, the alkanoyl group with a carboxyl group or can be substituted by one or two halogen atoms, or a benzoyl group, which can also carry one or two substituents, these substituents being halogen, nitro, amino, lower alkyl or lower alkoxy with 1-3 carbon atoms 2
can be, R is lower alkyl or lower alkoxy with 1-3 carbon atoms and R is hydrogen or lower alkyl with 1-6 carbon atoms, with the 2
Provided that R represents a lower alkyl group with 2 or 3 carbon atoms or a lower alkoxy group with 1-3 carbon atoms when R and R each represent hydrogen, or salts of such compounds, and contains inert carrier material. 2. Composition according to claim 1, characterized in that it is a compound of the formula
or a salt thereof. it is a compound of the formula I in which R is hydrogen, 3. Means according to claim 1 or 2, characterized in that 2 that it contains a compound of the formula I wherein R is a straight-chain or branched-chain alkyl group having 1-3 carbon atoms, or a salt thereof. 7098BR / 1004 OWQINAL INSPECT » 9L ■ j 4. Agent according to one of claims 1-3, characterized in that that it is a compound of the formula I in which R is hydrogen, a straight-chain or branched-chain alkyl group with 1-6 carbon atoms or a straight or branched chain lower alkanoyl group, which can be substituted by a carboxyl group or one or two halogen atoms, means, or a salt thereof. 5. Agent according to one of claims 1-4, characterized in that it contains 6-formamido-o-toluic acid. 6. Agent according to one of claims 1-5 in concentrate form, characterized in that it is 10-50% (percent by weight) on a compound of formula I. 7. Agent according to one of claims 1-5 in the form of a ready-to-spray solution, characterized in that it contains 0.0001-10% (percent by weight) of a compound of formula I. 8. Agent according to one of claims 1-5 in the form of a water-soluble powder, characterized in that it 10-90% (percent by weight) of a compound of the formula I contains. 9. Agent according to one of claims 1-5 in the form of a sprayable powder, characterized in that it is 35-65% (Percent by weight) of a compound of formula I contains. 10. Agent according to one of claims 1-5 in the form of dust powder or granules, characterized in that it contains 2-10% (percent by weight) of a compound of the formula I. 7 0 ^ ^f> 0/1004 1 11. Agent according to one of claims 1-5 in the form of a homogeneous, pourable preparation, ready to use in water Spray liquor is dispersible, characterized in that it contains 10-40% (percent by weight) of a compound of the 5 Formula I contains. 12. Agent according to one of claims 1-5 in the form of an emulsifiable concentrate, characterized in that it 5-50% (percent by weight) of a compound of the formula I. 10 contains. 13. Agent according to one of claims 1-5, characterized in that it is in addition to the inert carrier material further plant growth regulating, bactericidal, herbicidal 15 or contains fungicidal agents. 709886/1004 - vr - <f 273SAS7 14. A method for producing an agent for regulating plant growth or for weed killing, thereby characterized in that an effective amount of a compound of formula I in claim 1 with inert, solid or liquid Auxiliaries, as they are usual in such agents, mixed. 15. The method according to claim 14, characterized in that a compound of the formula I in which R is hydrogen means, or a salt thereof, is used. 7098RR / 100A -3S- 16. Compounds of the general formula COOH (Ia) wherein R is hydrogen, lower alkyl with 1-6 carbon atoms, lower alkanoyl, where the alkanoyl group can be substituted with a carboxyl group or one or two halogen atoms, or a benzoyl group which can additionally carry one or two substituents, these substituents being halogen, nitro , Amino, lower alkyl or lower alkoxy with 1-3 carbon atoms, R a lower alkyl or lower alkoxy group with 1-3 carbon atoms and R a hydrogen atom or an alkyl group with 1-6 carbon atoms, with the proviso that R is a lower Represents an alkyl group with 3 carbon atoms or a lower alkoxy group with 2 or 3 carbon atoms when R and R each represent hydrogen or that R represents a lower alkyl group with 1-3 carbon atoms or a lower alkoxy group with 2 or 3 carbon atoms when R represents the acetyl group and R represents mean a hydrogen atom,
and salts of these compounds. 17th Compound according to claim 16, characterized in that that R represents a hydrogen atom and salts thereof. 18 · Compound according to claim 16, characterized in that R is a straight-chain «
means and salts thereof. that R is a straight-chain or branched-chain alkyl group 70988K / 10 (H. 19. A compound according to claim 16, characterized in that that R is a hydrogen atom, a straight-chain or branched-chain Alkyl group with 1-6 carbon atoms or a straight chain or branched chain lower alkanoyl group replaced by a carboxyl group or one or two halogen atoms may be substituted means and salts thereof. 20. 6-methylamino-o-toluic acid. 21. 6-Formamido-o-toluic acid. 22. 6-acetamido-o-toluic acid. 23. 6-propionamido-o-toluic acid. 15th 24. 6-butyramido-o-toluic acid. 25. 6-Isobutyramido-o-toluic acid. 26. 6-Hexanamido-o-toluic acid. 27. 6- (2-Chloroacetamido) -o-toluic acid. 28. Ammonium salt of 2'-carboxy-3'-methylsuccinic anilide. 29. Ammonium salt of 6-formamido-o-toluic acid. 30. N-acetyl-6-ethylanthranilic acid. 31. 6-Benzamido-o-toluic acid. 32. 6- (6-Nitro-o-toluylamido) -o-toluic acid. 33. 6- (6-Amino-o-toluylamido) -o-toluic acid. 35 34. 6- (n-Propyl) anthranilic acid. 7 09 8 8 fi / 100A 3 5. 6-isopropyl anthranilic acid. 3 6. 6-Dimethylamino-o-toluic acid. 70988R / 1004 - 44- - 2735Λ57 37. Process for the preparation of compounds of the general formula COOH (Ia) wherein R ^{1 is} hydrogen, lower alkyl with 1-6 carbon atoms, lower alkanoyl, where the alkanoyl group can be substituted with a carboxyl group or one or two halogen atoms, or a benzoyl group which can additionally carry one or two substituents, these substituents being halogen, Nitro, amino, lower alkyl or lower alkoxy with 1-3 carbon atoms, R a lower alkyl or lower alkoxy group with 1-3 carbon atoms and R a hydrogen atom or an alkyl group with 1-6 carbon atoms, with the proviso that R a lower alkyl group having 3 carbon atoms or a lower alkoxy group having 2 or 3 carbon atoms 13th when R and R each represent hydrogen or that R represents a lower alkyl group with 1-3 carbon atoms or a lower alkoxy group with 2 or 3 carbon atoms when R represents the acetyl group and R 30 mean a hydrogen atom, and salts of these compounds, characterized in that one 709886/1004 a) the nitro group in a compound of the general formula COOH (II) wherein R has the meaning given above,
reduced, or b) for the preparation of a compound of the formula Ia, in which R is a lower alkyl group with 1-6 carbon atoms and R ■ | 5 is hydrogen, a corresponding compound of the formula Ia, in which R ur
alkylated or Ia, where R and R are hydrogen, correspondingly mono- c) for the preparation of a compound of the formula Ia, wherein R and R each represent a lower alkyl group with 1-6 carbon atoms, a corresponding compound of the formula Ia, where R is hydrogen or a lower alkyl group having 1-6 carbon atoms and R is hydrogen, reductively alkylated or d) for the preparation of a compound of the formula Ia in which R is a lower alkanoyl group which is linked to a carboxyl group or one or two halogen atoms or a benzoyl group, the benzoyl group being one or can carry two substituents and the substituents can be halogen, nitro and lower alkoxy with 1-3 carbon atoms, a corresponding compound of the formula Ia in which R is a hydrogen atom is acylated accordingly, or e) for the preparation of a compound of the formula Ia in which R is a benzoyl group and one or two amino substituents carries, a compound of the formula Ia in which R is a benzoyl group with one or two nitro substituents, reduced, or 709886/1004 - trio f) for the preparation of a compound of the formula Ia, wherein R and R each represent hydrogen, a compound of the general formula (III) wherein R has the meaning given above 10, oxidizes and, if necessary, a compound obtained from Formula Ia converted into a salt. 70988B / 10 (U