WO1995021174A1

WO1995021174A1 - Phenylimino-thiadiazabicycloalkane derivatives, processes and intermediates for their preparation and their use as herbicides

Info

Publication number: WO1995021174A1
Application number: PCT/EP1995/000253
Authority: WO
Inventors: Georg Pissiotas; Hans Moser; Hans-Georg Brunner
Original assignee: Ciba-Geigy Ag
Priority date: 1994-02-04
Filing date: 1995-01-25
Publication date: 1995-08-10
Also published as: EP0741733A1; IL112523A; JPH09508395A; CA2181583A1; AU1576095A; MX9603162A; ZA95864B; IL112523A0

Abstract

Compounds of formula (I): wherein R is C1-C6alkyl, C1-C6haloalkyl, C3-C6alkenyl, C3-C6alkynyl, C1-C4alkoxy or C3-C6cycloalkyl; R1 is halogen; R2 and R3 are each independently of the other C1-C4alkyl; R4 is halogen or a group of the formula -X-R5, -X-A-R6 or (a); R5 is hydrogen, C1-C6alkyl, C1-C8haloalkyl, C1-C4alkoxy-C1-C4alkyl, C1-C10alkylthio-C1-C4alkyl, C1-C4alkylamino-C1-C4alkyl, di-C1-C4alkylamino-C1-C4alkyl, cyano-C1-C8-alkyl, C3-C8alkenyl, C3-C8haloalkenyl, C3-C8alkynyl, C3-C6cycloalkyl, oxetanyl, C3-C7-halocycloalkyl, C3-C7cycloalkyl-C1-C4alkyl, phenyl-C1-C3alkyl that is unsubstituted or substituted in the phenyl ring by 1, 2 or 3 identical or different substituents selected from halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy and C1-C4haloalkoxy, or R5 is an alkali metal, alkaline earth metal or ammonium ion, or is the group -N=C(CH3)2, -CH2-O-N=C(CH3)2 or -CH2CH2-O-N=C(CH3)2; X is oxygen or sulfur; A is C1-C4 alkylene; R6 is a 5- or 6-membered heterocyclic ring that contains from 1 to 3 hetero atoms selected from the group oxygen, nitrogen and sulfur and that is bonded via the carbon or nitrogen atom to the alkylene chain A, it being possible for the heterocyclic ring in turn also to be benzene-fused and mono- or di-substituted by halogen, C1-C4alkyl, C1-C3haloalkyl, C1-C3alkoxy, C1-C3haloalkoxy, di-C1-C3alkylamino, hydroxy or by an oxy function; R7 is hydrogen, C1-C6alkyl, C1-C4haloalkyl, C1-C4alkoxy, C1-C4alkoxy-C1-C4alkyl, C3-C6alkenyl, C3-C6alkynyl, C3-C8cycloalkyl, hydroxy-C1-C4alkyl or cyano-C1-C4alkyl; R8 is hydrogen, C1-C6alkyl, C1-C4haloalkyl, C1-C4alkoxy-C1-C4-alkyl, hydroxy-C1-C4-alkyl, C3-C6alkenyl, phenyl or phenyl-C1-C3alkyl, the phenyl ring being unsubstituted or mono-, di- or tri-substituted by halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or by C1-C4haloalkoxy; or R7 and R8, together with the nitrogen atom to which they are bonded, form a pyrrolidino, piperidino, morpholino, thiomorpholino or piperazino ring that is unsubstituted or mono- or di-substituted by C1-C3alkyl; Z is oxygen or sulfur; n is 3, 4 or 5; and n1 is 0, 1, 2 or 3, and salts of those compounds, are suitable as herbicides for controlling weeds in crops of useful plants.

Description

Phenyl imino-thiadi azabycycloal kane derivatives, processes and intermedi ates for thei r preparation and their use as herbicides

The present invention relates to novel herbicidally active phenylimino-thiadiazabicycloalkanes, to a process for the preparation thereof, to compositions comprising those

compounds, and to the use thereof in the control of weeds, especially in crops of useful plants, or in the inhibition of plant growth.

Phenylimino-thiadiazabicyclononane compounds having herbicidal activity are known and are described, for example, in EP-A-0238 711.

Novel phenylimino-thiadiazabicycloalkanes having herbicidal and growth-inhibiting properties have now been found.

The present invention therefore relates to compounds of formula I

wherein

R is C₁-C₆alkyl, C₁-C₆haloalkyl, C₃-C₆alkenyl, C₃-C₆alkynyl, C₁-C₄alkoxy or C₃-C₆- cycloalkyl;

R₁ is halogen;

R₂ and R₃ are each independently of the other C₁-C₄alkyl; R₄ is halogen or a group of the formula -X-R₅, -X-A-R₆ or ;

R₅ is hydrogen, C₁-C₆alkyl, C₁-C₈haloalkyl, C₁-C₄alkoxy-C₁-C₄alkyl, C₁-C₁₀alkylthio- C₁-C₄alkyl, C₁-C₄ lkylamino-C₁-C₄alkyl, di-C₁-C₄alkylamino-C₁-C₄alkyl, cyano-C₁-C₈- alkyl, C₃-C₈alkenyl, C₃-C₈haloalkenyl, C₃-C₈alkynyl, C₃-C₆cycloalkyl, oxetanyl, C₃-C₇- halocycloalkyl, C₃-C₇cycloalkyl-C₁-C₄alkyl, phenyl- C₁-C₃alkyl that is unsubstituted or substituted in the phenyl ring by 1, 2 or 3 identical or different substituents selected from halogen, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy and C₁-C₄haloalkoxy, or R₅ is an alkali metal, alkaline earth metal or ammonium ion, or is the group -N=C(CH₃)₂,

-CH₂-O-N=C(CH₃)₂ or -CH₂CH₂-O-N=C(CH₃)₂;

X is oxygen or sulfur;

A is C₁-C₄alkylene;

R₆ is a 5- or 6-membered heterocyclic ring that contains from 1 to 3 hetero atoms selected from the group oxygen, nitrogen and sulfur and that is bonded via the carbon or nitrogen atom to the alkylene chain A, it being possible for the heterocyclic ring in turn also to be benzene-fused and mono- or di-substituted by halogen, C₁-C₄alkyl, C₁-C₃haloalkyl, C₁-C₃alkoxy, C₁-C₃haloalkoxy, di-C₁-C₃alkylamino, hydroxy or by an oxy function;

R₇ is hydrogen, C₁-C₆alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy, C₁-C₄alkoxy-C₁-C₄alkyl,

C₃-C₆alkenyl, C₃-C₆alkynyl, C₃-C₈cycloalkyl, hydroxy-C₁-C₄alkyl or cyano-C₁-C₄alkyl;

R₈ is hydrogen, C₁-C₆alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy-C₁-C₄alkyl, hydroxy-C₁-C₄- alkyl, C₃-C₆alkenyl, phenyl or phenyl-C₁-C₃alkyl, the phenyl ring being unsubstituted or mono-, di- or tri-substituted by halogen, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy or by C₁-C₄haloalkoxy; or

R₇ and R₈, together with the nitrogen atom to which they are bonded, form a pyrrolidino, piperidino, morpholino, thiomorpholino or piperazino ring that is unsubstituted or monoor di-substituted by C₁-C₃alkyl;

Z is oxygen or sulfur;

n is 3, 4 or 5; and

n, is 0, 1, 2 or 3,

and to salts of those compounds.

The alkyl groups that occur in the definitions of the substituents may be straight-chained or branched and are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl and the various isomers of pentyl and hexyl radicals. Methyl, ethyl, n-propyl, isopropyl and n-butyl are preferred.

Halogen is to be understood as being iodine, preferably fluorine, chlorine and bromine.

As haloalkyl there come into consideration alkyl groups that are mono- or poly-substituted, especially mono-, di- or tri-substituted, by halogen, the individual meanings of halogen being iodine and especially fluorine, chlorine and bromine, for example fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 2-fluoroethyl, 2-chloroethyl and 2,2,2-trichloroethyl; preferably difluorochloromethyl, trifluoromethyl, dichlorofluoromethyl and 2-chloroethyl. Alkoxy is, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy and tert-butoxy; preferably methoxy, ethoxy and isopropoxy.

Haloalkoxy is, for example, fluoromethoxy, difluoromethoxy, trifluoromethoxy, 2,2,2-tri-fluoroethoxy, 1,1,2,2-tetrafluoroethoxy, 2-fluoroethoxy, 2-chloroethoxy and 2,2,2-tri-chloroethoxy; preferably difluoromethoxy, trifluoromethoxy and 2-chloroethoxy.

Alkenyl is to be understood as being straight-chained or branched alkenyl, for example allyl, 1-methylallyl, methallyl, but-2-en-1-yl, pentenyl, 2-hexenyl and 3-heptenyl.

Alkenyl radicals having a chain length of 3 and 4 carbon atoms are preferred.

As haloalkenyl there come into consideration alkenyl groups that are mono- or polysubstituted by halogen, the individual meanings of halogen being bromine, iodine and, especially, fluorine and chlorine, for example 2- and 3-fluoroallyl, 2- and 3-chloroallyl, 2,3,3-tιifluoroallyl, 2,3,3-trichloroallyl, 4,4,4-trifluoro-but-2-en-1-yl and 4,4,4-trichlorobut-2-en-1-yl. 2- and 3-chloroallyl are preferred.

The alkynyl radicals that occur in the definitions of the substituents may be straight-chained or branched, for example propargyl, 3-butynyl, 1-methyIpropargyl, 1-pentynyl or 2-hexynyl. Propargyl and 1-methylpropargyl are preferred.

Cycloalkyl is, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.

Halocycloalkyl is, for example, 2,2-dichlorocyclopropyl and pentachlorocyclohexyl.

Alkoxyalkyl is, for example, methoxymethyl, ethoxymethyl, propoxymethyl, methoxyethyl, ethoxyethyl, propoxyethyl, butoxyethyl, methoxypropyl, ethoxypropyl and propoxypropyl.

Alkylthioalkyl is, for example, methylthiomethyl, ethylthiomethyl, methylthioethyl, methylthio-prop-2-yl, ethylthioethyl, ethylthio-prop-2-yl, propylthio-prop-2-yl, isopropylthioethyl, isopropylthio-prop-2-yl, n-butylthio-prop-2-yl and n-pentylthio-prop-2-yl.

Alkylamino is, for example, methylamino, ethylamino and the isomers of propyl- and butyl-amino.

Dialkylamino is, for example, dimethylamino, methylethylamino, diethylamino and the isomers of dipropyl- and dibutyl-amino.

Cyanoalkyl is, for example, cyanomethyl, cyanoethyl, cyanoeth-1-yl and cyanopropyl.

Hydroxyalkyl is, for example, hydroxymethyl, hydroxyethyl and 3-hydroxypropyl.

Phenyl, including part of a substituent such as phenylalkyl, may generally be unsubstituted or substituted. In the latter case, the substituents may be in the ortho-, meta- and/or para-position with respect to the ring linkage site. Preferred positions for the substituents are the ortho- and para-positions. Preferred substituents are halogen atoms and alkyl, haloalkyl, alkoxy and haloalkoxy groups.

A as an alkylene chain may be straight-chained or branched and is, for example, methylene, ethylene, methylethylene, propylene, 1-methyl-propylene and butylene;

preferably methylene and ethylene.

R₆ as a 5- or 6-membered heterocyclic ring is an unsaturated or completely or partially saturated heterocycle, for example 2-, 3- or 4-pyridyl, N-piperidyl, 2-thienyl, 2-furyl, 2-tetrahydrothienyl, 2-tetrahydrofuryl, N-morpholinyl and N-imidazolyl. Those heterocycles may in turn be substituted, for example 1-methyl-4-pyrazolyl, 4-methyl-5-thiazolyl and 2-pyrrolidon-1-yl.

The substituents in definitions composed of several elements, for example cycloalkylalkyl, alkylamino-alkyl and dialkylamino-alkyl, may also be given corresponding meanings.

The salts of compounds of formula I containing acid protons, especially the salts of the derivatives containing carboxylic acid groups (R₄ is the group of the formula -X-R₅, wherein X is oxygen and R₅ is hydrogen), are, for example, alkali metal salts, e.g. sodium and potassium salts; alkaline earth metal salts, e.g. calcium and magnesium salts;

ammonium salts, i.e. unsubstituted ammonium salts and mono- or poly-substituted ammonium salts, e.g. triethylammonium and methylammonium salts; or salts with other organic bases. Of the alkali metal and alkaline earth metal hydroxides as salt-forming substances, special mention is to be made of the hydroxides of lithium, sodium, potassium, magnesium and calcium, but especially those of sodium and potassium.

Examples of amines that are suitable for the formation of ammonium salts are both ammonia and primary, secondary and tertiary C₁-C₁galkylamines, C₁-C₄hydroxyalkylamines and C₂-C₄alkoxyalkylamines, for example methylamine, ethylamine, n-propylamine, isopropylamine, the four isomers of butylamine, n-amylamine, isoamylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, methyl-ethylamine, methyl-isopropylamine, methyl-hexylamine, methyl-nonylamine, methyl-pentadecylamine, methyl-octadecylamine, ethyl-butylamine, ethyl-heptylamine, ethyl-octylamine, hexyl-heptylamine, hexyl-octylamine, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, di-n-amylamine, diisoamylamine, dihexylamine, diheptylamine, dioctylamine, ethanolamine, n-propanolamine, isopropanolamine, N,N-diethanolamine, N-ethyl-propanolamine, N-butylethanolamine, allylamine, n-butenyl-2-amine, n-pentenyl-2-amine, 2,3-dimethylbutenyl-2-amine, dibutenyl-2-amine, n-hexenyl-2-amine, propylenediamine, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, tri-isobutylamine, tri-sec-butylamine, tri-n-amylamine, methoxyethylamine and ethoxyethylamine; heterocyclic amines, for example pyridine, quinoline, isoquinoline, morpholine, thiomorpholine, N-methylmorpholine, N-methyl-thiomorpholine, piperidine, pyrrolidine, indoline, quinuclidine and azepine; primary arylamines, for example anilines, methoxyanilines, ethoxyanilines, o-, m- and p-toluidines, phenylenediamines, benzidines, naphthylamines and o-, m- and p-chloroanilines; but especially triethylamine, isopropylamine and diisopropylamine.

The possible presence of at least one asymmetric carbon atom in the compounds of formula I, for example in the ester derivatives containing substituted aliphatic and alicyclic groups and the substituents R₅, A and R₆ may contain

asymmetric carbon atoms), means that the compounds may be obtained either as optically active individual isomers or in the form of racemic mixtures. In the present invention, the compounds of formula I are to be understood as including both the pure optical antipodes and the racemates. Unless specific reference is made to the individual optical antipodes, the given formula is to be understood as meaning those racemic mixtures that are formed in the preparation process indicated. If an aliphatic C=C or C=N-O double bond (syn/anti) is present, then geometrical isomerism may also occur.

Preference is given to compounds of formula I wherein n is 3 or 4. Of those compounds of formula I, those wherein n is 4 are especially preferred.

Preference is given also to compounds of formula I wherein % is 0, 1 or 2 and R is C₁-C₃- alkyl.

Also preferred are compounds of formula I wherein R₄ is the group -X-R₅. Of those compounds of formula I, those wherein X is oxygen are especially preferred.

Of those compounds, special preference is given to those wherein R₅ is C₁-C₆alkyl.

Also preferred are compounds of formula I wherein R₂ and R₃ are methyl.

Preferred compounds of formula I are also those wherein n₂ is 0, 1 or 2; R is methyl; R₁ is chlorine or bromine; R₂ and R₃ are methyl; R₄ is the group -X-R₅; R₅ is C₁-C₆alkyl; and X and Z are oxygen.

Preference is given also to compounds of formula I wherein R₄ is the group -X-A-R₆. Of those compounds of formula I, those wherein X is oxygen and A is a C₁- or C₂-alkylene bridge are especially preferred.

Prefeιτed compounds are those wherein n₂ is 0, 1 or 2; R is methyl; R₁ is chlorine or bromine; R₂ and R₃ are methyl; R₄ is the group -X-A-R₆; and X and Z are oxygen. Also preferred are compounds of formula I wherein R₄ is the group

Also preferred are compounds of formula I wherein n₁ is 0, 1 or 2; R is methyl; R₁ is chlorine or bromine; R₂ and R₃ are methyl; R₄ is the group ; and Z is oxygen.

There are suitable compounds of formula la

wherein

R₁ is chlorine or bromine;

R₅ is hydrogen, C₁-C₅alkyl, C₂chloroalkyl, C₁- or C₂-alkoxy-C₂- or -C₃-alkyl, C₁-C₅alkylthio-C₂- or -C₃-alkyl, di-C₁- or -C₂-alkylamino-C₃alkyl, cyano-C₁- or -C₂-alkyl, C₃- or C₄-alkenyl, C₃chloroalkenyl, C₃- or C₄-alkynyl, C₅- or C₆-cycloalkyl, C₃- or C₅-cycloalkyl-C₁- or -C₂-alkyl, phenyl-C₁- or -C₂-alkyl that is unsubstituted or monosubstituted in the phenyl ring by chlorine or by methyl, or R₅ is the group -N=C(CH₃)₂ or

-CH₂CH₂-O-N=C(CH₃)₂, or is a sodium, potassium, ammonium, diethylammonium, triethylammonium, ethanolammonium, diethanolammonium, triethanolammonium, morpholinium, thiomorpholinium, pyrrolidinium or piperidinium ion; and

X is oxygen or sulfur.

Also suitable are compounds of formula lb

wherein

R₁ is chlorine or bromine;

X is oxygen;

A is C₁- or C₂-alkylene; and

R₆ is 2-furyl, 2-tetrahydrofuryl, 2-thienyl, 2-, 3- or 4-pyridyl, 4-methyl-5-thiazolyl, pyrrolidin-2-on-1-yl, N-morpholinyl, N-piperidyl, 1-imidazolyl or 1-methyl-4-pyrazolyl. Further suitable compounds are those of formula Ic

wherein

R₁ is chlorine or bromine;

R₇ is hydrogen, C₁-C₄alkyl, C₃alkenyl, methoxy, C₃-C₈cycloalkyl or cyano- or hydroxy-

C₂alkyl; and

R₈ is hydrogen, C₁-Csalkyl, C₂chloroalkyl, methoxy- C₂alkyl, hydroxy-C₂alkyl, C₃- or

C₄-alkenyl, C₃chloroalkenyl, C₃- or C₄-alkynyl, phenyl, phenyl monosubstituted by chlorine, methyl, methoxy or by trifluoromethyl, benzyl or benzyl monosubstituted in the phenyl ring by chlorine or by methyl; or

R₇ and R₈, together with the nitrogen atom to which they are bonded, form a pyrrolidino, morpholino, thiomorpholino, N-methylpiperazino or 3,5-dimethylmorpholino ring.

Also suitable are compounds of formula Id

wherein

R is hydrogen or methyl;

R₁ is chlorine;

X is oxygen or sulfur; and

R₅ is hydrogen, C₁-C₃alkyl, C₃- or C₄-alkenyl, C₃chloroalkenyl, C₃alkynyl, C₁- or C₂- alkoxy-C₂alkyl or C₁- or C₂-alkylthio-C₃alkyl. There are also suitable compounds of formula le

wherein

R₁ is chlorine;

X is oxygen; and

R₅ is C₁-C₃alkyl, C₃- or C₄-alkenyl, C₃chloroalkenyl, C₃alkynyl, methylthio-C₃alkyl, C₆- cycloalkyl or the group -N=C(CH₃)₂.

Also suitable are compounds of formula If

wherein

R₁ is chlorine or bromine;

X is oxygen;

A is C₁- or C₂-alkylene; and

R₆ is 2-furyl, 2-tetrahydrofuryl, 4-methyl-5-thiazolyl, N-piperidyl, N-methylpiperazinyl or

N-morpholinyl.

There are suitable compounds of formula Ig

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

R₇ is hydrogen, C₁-C₄alkyl, C₃alkenyl, methoxy or C₃cycloalkyl; and

R₈ is hydrogen, C₁-C₄alkyl, C₃alkenyl, C₃chloroalkenyl, C₃alkynyl, phenyl, chlorophenyl or phenyl-C₁- or -C₂-alkyl.

Also suitable are compounds of formula Hi

wherein

R₁ is chlorine;

R₇ is hydrogen, methyl, methoxy, C₃alkenyl or C₃cycloalkyl; and

R₈ is hydrogen, C₁-C₄alkyl or C₃- or C₄-alkenyl; or

R₇ and R₈, together with the nitrogen atom to which they are bonded, form a morpholino ring.

There are also suitable compounds of formula Ii

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

X is oxygen or sulfur; and

R₅ is hydrogen, C₁-C₃alkyl, methoxy-C₂alkyl, C₂- or C₃-alkylthio-C₃ alkyl, C₃- or C₄- alkenyl, C₃chloroalkenyl, C₃alkynyl, C₆cycloalkyl, C₃cycloalkyl-C₂alkyl, phenyl-C₁- or

-C₂-alkyl or the group -N=C(CH₃)₂.

Suitable compounds are also those of formula Ij

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

X is oxygen;

A is C₁- or C₂-alkylene; and

R₆ is 2-furyl, 2-tetrahydrofuryl, 2-tetrahydrothienyl, N-morpholinyl, N-piperidyl, 2-, 3- or

4-pyridyl or 4-methyl-5-thiazolyl.

There are also suitable compounds of formula Ik

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

R₇ is hydrogen, methyl, methoxy, C₃cycloalkyl or C₃alkenyl; and

R₈ is hydrogen, C₁-C₄alkyl, hydroxy-C₂alkyl, C₃alkenyl, C₃chloroalkenyl, C₃- or C₄- alkynyl, phenyl, fluorophenyl, methoxyphenyl or benzyl; or

A very especially preferred individual compound within the scope of formula I is

2-methyl-2-[2-chloro-5-[(tetrahydro-3-oxo-1H,3H-[1,3,4]thiadiazolo[3,4-a]pyridazin-1-ylidene)amino]-benzoyloxy]-propionic acid 2-chloro-2-propenyl ester.

The process according to the invention for the preparation of the compounds of formula I is carried out analogously to known processes and comprises reacting an aniline derivative of formula II

with thiophosgene to form the isothiocyanate of formula III

the radicals R₁ to R₄ in the compounds of formulae II and III being as defined under formula I, and converting the isothiocyanate with a compound of formula V

wherein R n and n₁ are as defined under formula I into the compound of formula IV ,

wherein R, R₁ to R₄, n and n₁ are as defined, and then reacting the compound of formula IV with a compound of formula VI

CZCl₂ (VI), wherein Z is oxygen or sulfur, if desired in the presence of a base.

The reaction of the aniline derivatives of formula II to form the isothiocyanates of formula III is carried out analogously to known processes, for example as described in EP-A-0 304 920, EP-A-0238 711, EP-A-0 409 025, EP-A-0 372461, EP-A-0 311 135 and DE-OS-3 724098.

The reaction of the isothiocyanates of formula III with the compounds of formula V is advantageously carried out in a solvent that is inert towards the reaction, at temperatures of from -5°C to the boiling temperature of the solvent, especially from 0 to +50°C, especially preferably at room temperature. Suitable solvents for this reaction are, for example, toluene, xylene, ethyl acetate and acetonitrile.

The reaction of the compound of formula IN with the compound of formula VI is advantageously carried out in an inert organic solvent at low temperatures, preferably at from 0 to +50°C, especially preferably at from 0 to + 15°C. Suitable bases for this reaction are, for example, pyridine, triethylamine and Ν,Ν-dimethylaniline. Suitable solvents are, for example, 1,2-dichloroethane, dichloromethane and toluene. The aniline derivatives of formula II, the isothiocyanates of formula III and the compounds of formula IN are novel and have been developed specifically for the synthesis of the compounds of formula I. The present invention therefore relates also thereto.

The novel intermediates of formula IN are also distinguished by herbicidal activity, with selectivity in the case of certain cultivated plants.

For the intermediates of formulae II, III and IV, the same preferences as those given for the compounds of formula I apply with respect to R, R₁ to R₄, n and n₁.

The starting materials of formula V, wherein R is alkyl and n₁ is as defined under formula I, required for the preparation process according to the invention are known and can be prepared analogously to processes known in the literature. The preparation of such compounds from dibromoalkanes and hydrazine is described, for example, in Archiv der Pharmazie 295 (7), 526 (1962), J. Org. Chem. 46, 442 (1981), Bull. Soc. Chim. France 1957, 704; EP-A-0 304920, pages 9-11 (schemes 2-4), EP-A-0468 924, page 19, last section, page 20, first section and page 28, Example H18, and J. Am. Chem. Soc. 88, 3959 (1966).

Compounds of formula Va (dihydrobromide)

wherein R and n₁ are as defined under formula I, can be prepared in accordance with reaction scheme 1.

In reaction scheme 1, formulae IXX, IXXa and IXXb are each an unbranched aliphatic pentane chain to the terminal carbon atoms C₁ and C₅ of which there is bonded a hydroxy group (IXX) or a group R₀SO₂O (IXXb) or bromine (IXXa). The radical R may be linked 0, 1, 2 or 3 times, if desired also geminally, with all five carbon atoms in the n-pentane chain.

The aniline derivatives of formula II required for the preparation process according to the invention can be prepared analogously to known processes. Those preparation processes are illustrated in greater detail in reaction scheme 2 below.

The starting materials of formulae VII, VIII, X, X II, XIII and XV, wherein R₁ to R₃, R₅ to R₈, X and A are as defined above, are known and can be prepared according to the disclosed processes, as described, for example, in US-A-5 183492 and EP-A-0408 382.

The nitrobenzoic acid ester derivatives of formulae XI, XVI and XNm are novel and have been developed specifically for the synthesis of the compounds of formula I. The present invention therefore relates also thereto. The reactions to form compounds of formula I are advantageously carried out in aprotic, inert organic solvents. Such solvents are pure hydrocarbons, such as benzene, toluene, xylene or cyclohexane, chlorinated hydrocarbons, such as dichloromethane, trichloromethane, tetrachloromethane, ethylene chloride or chlorobenzene, ethers, such as diethyl ether, tert-butyl methyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran or dioxane, nitriles, such as acetonitrile or propionitrile, and ketones, such as acetone or methyl ethyl ketone. The reduction of the nitrobenzoic acid ester derivatives of formulae XI, XNI and XNIII is advantageously carried out in dioxane or protic, organic solvents, for example alcohols, such as methanol, ethanol or propanol, in the presence of an organic or inorganic acid, for example hydrochloric acid. The isothiocyanates of formula III are advantageously prepared in a two-phase system, for example a solvent mixture of ethylene chloride and water. The reaction temperatures are from -10°C to the reflux temperature of the reaction mixture, preferably in the temperature range of from 0°C to 120°C.

The end products of formula I can be isolated in customary manner by concentration and/or evaporation of the solvent and can be purified by recrystallisation or trituration of the solid residue in solvents in which they are not readily soluble, such as ethers, aromatic hydrocarbons or chlorinated hydrocarbons, by distillation or by means of column chromatography and a suitable eluant.

For the use according to the invention of the compounds of formula I or of compositions comprising them, there come into consideration all methods of application customarily used in agriculture, for example preemergence application, postemergence application and seed dressing, as well as different methods and techniques, for example controlled release of the active ingredient For that purpose, the active ingredient is applied in solution to granulated mineral carriers or polymerised granules (urea/formaldehyde) and is dried. Where appropriate, a coating may additionally be applied (coated granules), which allows the active ingredient to be released in metered amounts over a particular period of time.

The compounds of formula I can be used in unmodified form, i.e. as obtained in the synthesis, but preferably they are formulated in customary manner together with the adjuvants conventionally employed in formulation technology to form e.g. emulsifiable concentrates, directly sprayable or dilutable solutions, dilute emulsions, wettable powders, soluble powders, dusts, granules or microcapsules. As with the nature of the compositions, the methods of application, such as spraying, atomising, dusting, wetting, scattering or pouring, are chosen in accordance with the intended objectives and the prevailing circumstances.

The formulations, i.e. the compositions, preparations or mixtures comprising the compound (active ingredient) of formula I or at least one compound of formula I and, where appropriate, one or more solid or liquid formulation adjuvants, are prepared in known manner, e.g. by homogeneously mixing and/or grinding the active ingredients with the formulation adjuvants, e.g. solvents or solid carriers. In addition, surface-active compounds (surfactants) may also be used in the preparation of the formulations.

Suitable solvents are: aromatic hydrocarbons, preferably the fractions containing 8 to 12 carbon atoms, such as mixtures of alkylbenzenes, e.g. xylene mixtures or alkylated naphthalenes; aliphatic and cycloaliphatic hydrocarbons, such as paraffins, cyclohexane or tetrahydronaphthalene; alcohols, such as ethanol, propanol or butanol; glycols and their ethers and esters, such as propylene glycol or dipropylene glycol ether; ketones, such as cyclohexanone, isophorone or diacetone alcohol; strongly polar solvents, such as

N-methyl-2-pyrrolidone, dimethyl sulfoxide or water; vegetable oils and their esters, such as rape oil, castor oil or soybean oil; and, where appropriate, also silicone oils.

The solid carriers used, e.g. for dusts and dispersible powders, are normally natural mineral fillers, such as calcite, talcum, kaolin, montmorillonite or attapulgite. In order to improve the physical properties it is also possible to add highly dispersed silicic acid or highly dispersed absorbent polymers. Suitable granulated adsorptive carriers are porous types, for example pumice, broken brick, sepiolite or bentonite; and suitable nonsorbent carriers are, for example, calcite or sand. In addition, a great number of pregranulated materials of inorganic or organic nature can be used, e.g. especially dolomite or pulverised plant residues.

Depending on the nature of the compound of formula I to be formulated, suitable surface-active compounds are non-ionic, cationic and/or anionic surfactants having good emulsifying, dispersing and wetting properties. The term "surfactants" will also be understood as comprising mixtures of surfactants.

Both so-called water-soluble soaps and water-soluble synthetic surface-active compounds are suitable anionic surfactants. Suitable soaps are the alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts of higher fatty acids (C₁₀-C₂₂), e.g. the sodium or potassium salts of oleic or stearic acid, or of natural fatty acid mixtures which can be obtained e.g. from coconut oil or tallow oil. Mention may also be made of fatty acid methyltaurin salts.

More frequently, however, so-called synthetic surfactants are used, especially fatty alcohol sulfonates, fatty alcohol sulfates, sulfonated benzimidazole derivatives or alkylarylsulfonates.

The fatty alcohol sulfonates or sulfates are usually in the form of alkali metal salts, alkaline earth metal salts or unsubstituted or substituted ammonium salts and contain a C₈-C₂₂alkyl radical, which also includes the alkyl moiety of acyl radicals, e.g. the sodium or calcium salt of lignosulf onic acid, of dodecyl sulfate or of a mixture of fatty alcohol sulfates obtained from natural fatty acids. These compounds also comprise the salts of sulfated and sulfonated fatty alcohol/ethylene oxide adducts. The sulfonated benzimidazole derivatives preferably contain 2 sulfonic acid groups and one fatty acid radical containing 8 to 22 carbon atoms. Examples of alkylarylsulfonates are the sodium, calcium or triethanolamine salts of dodecylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, or of a condensate of naphthalenesulfonic acid and formaldehyde.

Also suitable are corresponding phosphates, e.g. salts of the phosphoric acid ester of an adduct of p-nonylphenol with 4 to 14 mol of ethylene oxide, or phospholipids.

Non-ionic surfactants are preferably polyglycol ether derivatives of aliphatic or cycloaliphatic alcohols, saturated or unsaturated fatty acids and alkylphenols, said derivatives containing 3 to 30 glycol ether groups and 8 to 20 carbon atoms in the

(aliphatic) hydrocarbon moiety and 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts of polyethylene oxide with polypropylene glycol, ethylenediaminopolypropylene glycol and alkylpolypropylene glycol containing 1 to 10 carbon atoms in the alkyl chain, which adducts contain 20 to 250 ethylene glycol ether groups and 10 to 100 propylene glycol ether groups. These compounds usually contain 1 to 5 ethylene glycol units per propylene glycol unit

Representative examples of non-ionic surfactants are nonylphenol polyethoxyethanols, castor oil polyglycol ethers, polypropylene/polyethylene oxide adducts, tributylphenoxypolyethoxyethanol, polyethylene glycol and octylphenoxypolyethoxyethanol.

Fatty acid esters of polyoxyethylene sorbitan, e.g. polyoxyethylene sorbitan trioleate, are also suitable non-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts which contain, as

N-substituent, at least one C₈-C₂₂alkyl radical and, as further substituents, unsubstituted or halogenated lower alkyl, benzyl or hy droxy-lower alkyl radicals. The salts are preferably in the form of halides, methyl sulfates or ethyl sulfates, e.g. stearyltrimethylammonium chloride or benzyldi(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in formulation technology, which may also be used in the compositions according to the invention, are described inter alia in "McCutcheon's Detergents and Emulsifiers Annual", MC Publishing Corp., Ridgewood New Jersey, 1981, Stache, H., "Tensid-Taschenbuch", Carl Hanser Verlag, Munich/Vienna, 1981 and M. and J. Ash, "Encyclopedia of Surfactants", Vol.1-113, Chemical Publishing Co., New York, 1980-1981.

The herbicidal compositions usually comprise 0.1 to 99 %, preferably 0.1 to 95 %, of a compound of formula 1, 1 to 99.9 % of a solid or liquid formulation adjuvant, and 0 to 25 %, preferably 0.1 to 25 %, of a surfactant.

Whereas commercial products will preferably be formulated as concentrates, the end user will normally employ dilute formulations.

The compositions may also comprise further auxiliaries such as stabilisers, e.g. vegetable oils or epoxidised vegetable oils (epoxidised coconut oil, rape oil or soybean oil), antifoams, e.g. silicone oil, preservatives, viscosity regulators, binders, tackifiers as well as fertilisers or other active ingredients.

Preferred formulations have especially the following composition (throughout,

percentages are by weight): Emulsifiable concentrates:

active ingredient: 1 to 90 %, preferably 5 to 50 %

surface-active agent: 5 to 30 %, preferably 10 to 20 %

solvent: 15 to 94 %, preferably 70 to 85 %

Dusts:

active ingredient: 0.1 to 50 %, preferably 0.1 to 1 %

solid carrier: 99.9 to 90 %, preferably 99.9 to 99 %

Suspension concentrates:

active ingredient: 5 to 75 %, preferably 10 to 50 %

water: 94 to 24 %, preferably 88 to 30 %

surface-active agent: 1 to 40 %, preferably 2 to 30 %

Wettable powders:

active ingredient: 0.5 to 90 %, preferably 1 to 80 %

surface-active agent: 0.5 to 20 %, preferably 1 to 15 %

solid carrier: 5 to 95 %, preferably 15 to 90 %

Granules:

active ingredient: 0.1 to 30 %, preferably 0.1 to 15 %

solid carrier: 99.5 to 70 %, preferably 97 to 85 %

The compounds of formula I are generally employed successfully on the plant or the locus thereof at rates of application of from 0.001 to 2 kg/ha, especially from 0.005 to 1 kg/ha. The rate of application required to achieve the desired effect may be determined by experiments. It is dependent on the type of action, the stage of development of the cultivated plant and of the weeds, and on the application (place, time, method) and, in dependence on those parameters, may vary within a wide range.

The compounds of formula I are distinguished by herbicidal and growth-inhibiting properties, which render them excellently suitable for use in crops of useful plants.

Crops are to be understood as including crops which have been rendered tolerant to herbicides or classes of herbicides by conventional cultivation or genetic engineering methods. The following Examples illustrate the invention in greater detail but do not limit the invention.

Preparation Examples:

Example P1: 2-Chloro-5-nitrobenzoic acid 1-(2-chloroallyloxycarbonyl)-1-methyl ethyl ester (intermediate)

4.0 ml of 2,3-dichloro-1-propene are added dropwise at 20°C to a mixture of 12.0 g of 2-chloro-5-nitrobenzoic acid 1-(oxycarbonyl)-1-methyl ethyl ester and 6.3 g of potassium carbonate in 200 ml of methyl ethyl ketone (exothermic reaction). The resulting reaction mixture is stirred overnight at 20°C. The inorganic components are then filtered off and washed with methyl ethyl ketone. The resulting organic phase is concentrated by evaporation and the residue is purified by means of column chromatography on silica gel (eluant hexane/ethyl acetate 1/1), yielding 7.7 g of the desired product having a refractive index n_D ²⁰ 1.5312 .

Example P2: 2-Chloro-5-aminobenzoic acid 1-(2-chloroallyIoxycarbonyl)-1-methyl ethyl ester (intermediate)

A solution of 7.7 g of 2-chloro-5-nitrobenzoic acid 1-(2-chloroallyloxycarbonyl)-1-methyl ethyl ester (Example PI) in 50 ml of ethanol is added dropwise to a mixture, heated to boiling temperature, consisting of 5.0 g of iron powder, 2.0 ml of concentrated hydrochloric acid in 50 ml of water and 50 ml of ethanol, and the reaction mixture is stirred for 6 hours at boiling temperature. After cooling the reaction mixture, the inorganic components are filtered off, the filtrate is rendered alkaline with aqueous sodium hydrogen carbonate solution, and extraction is carried out with ethyl acetate. The combined extracts are dried over sodium sulfate and concentrated by evaporation, yielding 6.5 g of 2-chloro5-aminobenzoic acid 1-(2-chloroallyloxycarbonyl)-l -methyl ethyl ester having a refractive index n_D ²⁰1.5439

Example P3: 2-Chloro-5-isothiocvanatobenzoic acid 1-(2-chloroallyloxycarbonyI)-1- methyl ethyl ester (intermediate)

A solution of 6.5 g of 2-chloro-5-amino-1-(2-chloroallyloxycarbonyl)-1-methyl ethyl ester in 20 ml of ethylene chloride is added dropwise at 20°C, with stirring, to a mixture of 4.0 g of calcium carbonate, 2.0 ml of thiophosgene in 30 ml of ethylene chloride and 30 ml of water, and the mixture is stirred for a further 6 hours. The inorganic components are then filtered off and the organic phase is dried over calcium chloride and is then concentrated by evaporation, yielding 7.3 g of the desired product in the form of an oil.

Example P4: 2-Chloro-5-[(1-hexahydropyridazinyI)-thiocarbonylamino]-benzoic acid 1-(2-chloroallyloxycarbonyl)-1-methyl ethyl ester (intermediate)

A solution of 7.3 g of 2-chloro-5-isothiocyanatobenzoic acid 1-(2-chloroallyloxycarbonyl)-1-methyl ethyl ester in 30 ml of ethylene chloride is added dropwise at 5°C, with stirring, to a solution of 2.0 g of hexahydropyridazine in 30 ml of ethanol, and the mixture is stirred for a further 3 hours at 20 °C. The reaction mixture is then concentrated by evaporation in vacuo, yielding 8.3 g of the desired product having a refractive index n_D ²⁰1.5738 . Example P5: 2-Methyl-2-[2-chloro-5-[(tetrahvdro-3-oxo-1H,3H-[1,3,41thiadiazolo[3,4-a]- pyridazin-1-ylidene)amino]-benzoyloxy]-propionic acid 2-chloro-2-propenyl ester

A solution of 6.0 g of 2-chloro-5-[(1-hexahydropyridazinyl)-thiocarbonylamino]-benzoic acid 1-(2-chloroallyloxycarbonyl)-1-methyl ethyl ester in 30 ml of ethylene chloride is added dropwise to a solution of 6.5 ml of 20 % phosgene in toluene at a temperature of 0-5°C. The reaction mixture is then stirred for 6 hours at 20°C and is then poured onto ice-water. The organic phase is separated off and dried over sodium sulfate.

Concentration of the organic phase by evaporation yields 5.5 g of the desired product in the form of an oil; refractive index n_D ²⁰ 1.5811.

The compounds listed in the following Tables can be prepared in an analogous manner.

Formulation Examples for compounds of formula I

(throughout, percentages are by weight)

Fl. Emulsifiable concentrates a) b) c) d) a compound of Tables 1-11 5% 10 % 25 % 50 % calcium dodecylbenzenesulfonate 6% 8% 6 % 8 % castor oil polyglycol ether 4% - 4 % 4 %

(36 mol of ethylene oxide)

octylphenol polyglycol ether - 4 % - 2 %

(7-8 mol of ethylene oxide)

cyclohexanone - - 10 % 20 % aromatic hydrocarbon mixture 85 % 78 % 55 % 16 %

C₉-C₁₂

Emulsions of any desired concentration can be produced from such concentrates by dilution with water.

F2. Solutions a) b) c) d) a compound of Tables 1-11 5 % 10 % 50 % 90 % dipropylene glycol methyl ether - 20 % 20 % - polyethylene glycol 20 % 10 % _ _

(mol. wt.400)

N-methyl-2-pyrrolidone - - 30 % 10 % aromatic hydrocarbon mixture 75 % 60 % - -

C₉-C₁₂

These solutions are suitable for application in the form of micro-drops.

F3. Wettable powders a) b) c) d) a compound of Tables 1-11 5 % 25 % 50 % 80 % sodium lignosulfonate 4 % - 3 % - sodium laurylsulfate 2 % 3 % - 4 % sodium dϋsobutylnaphthalene- - 6 % 5 % 6 % sulfonate

octylphenol polyglycol ether -- 1 % 2 % -

(7-8 mol of ethylene oxide) highly dispersed silicic acid 1 % 3 % 5 % 10 % kaolin 88 % 62 % 35 %

The active ingredient is thoroughly mixed with the adjuvants and the mixture is thoroughly ground in a suitable mill, affording wettable powders which can be diluted with water to give suspensions of the desired concentration.

F4. Coated granules a) b) c)

a compound of Tables 1-11 0.1 % 5 % 15 % highly dispersed silicic acid 0.9 % 2 % 2 % inorganic carrier 99.0 % 93 % 83 %

(diameter 0.1-1 mm)

e.g. CaCO₃ or SiO₂

The active ingredient is dissolved in methylene chloride, the solution is sprayed onto the carrier, and the solvent is subsequently evaporated off in vacuo.

F5. Coated granules a) b) c)

a compound of Tables 1-11 0.1 % 5 % 15 % polyethylene glycol 1.0 % 2 % 3 %

(mol. wt 200)

highly dispersed silicic acid 0.9 % 1 % 2 % inorganic carrier 98.0 % 92 % 80 %

(diameter 0.1 - 1 mm)

e.g. CaCO₃ or SiO₂

The finely ground active ingredient is uniformly applied, in a mixer, to the carrier moistened with polyethylene glycol. Non-dusty coated granules are obtained in this manner.

F6. Extruder granules a) b) c) d) a compound of Tables 1-11 0.1 % 3 % 5 % 15 % sodium lignosulfonate 1.5 % 2 % 3 % 4 % carboxymethylcellulose 1.4 % 2 % 2 % 2 % kaolin 97.0 % 93 % 90 % 79 % The active ingredient is mixed and ground with the adjuvants, and the mixture is moistened with water. The mixture is extruded and then dried in a stream of air.

F7. Dusts a) b) c)

a compound of Tables 1-11 0.1 % 1 % 5 %

talcum 39.9 % 49 % 35 %

kaolin 60.0 % 50 % 60 %

Ready-for-use dusts are obtained by mixing the active ingredient with the carriers and grinding the mixture in a suitable mill.

F8. Suspension concentrates a) b) c) d) a compound of Tables 1-11 3 % 10 % 25 % 50 % ethylene glycol 5 % 5 % 5 % 5 % nonylphenol polyglycol ether - 1 % 2 % -

(15 mol of ethylene oxide)

sodium lignosulfonate 3 % 3 % 4 % 5 % carboxymethylcellulose 1 % 1 % 1 % 1 %

37% aqueous formaldehyde 0.2 % 0.2 % 0.2 % 0.2 % solution

silicone oil emulsion 0.8 % 0.8 % 0.8 % 0.8 % water 87 % 79 % 62 % 38 %

The finely ground active ingredient is intimately mixed with the adjuvants, giving a suspension concentrate from which suspensions of any desired concentration can be obtained by dilution with water.

Biological Examples

Example B1: Preemergence herbicidal action

Monocotyledonous and dicotyledonous test plants are sown in plastics pots in standard soil. Immediately after sowing, the plants are sprayed with an aqueous suspension of the test compounds prepared from a 25 % wettable powder (Formulation Example F3, b)), corresponding to a rate of application of 2 kg a.i./ha (5001 water/ha). The test plants are then cultivated in a greenhouse under optimum conditions. Three weeks later, the test is evaluated using a scale of nine ratings (1 = total damage, 9 = no action). Ratings of from 1 to 4 (especially from 1 to 3) indicate good to very good herbicidal action.

Test plants: Setaria, Sinapis, Solanum, Stellaria.

In this test, compounds of Tables 1 to 11 exhibit pronounced herbicidal activity.

An example of the good herbicidal activity is shown in Table B1.

Table B1: Preemergence action

Test plant: Setaria Sinapis Solanum Stellaria

Compound no.

1.027 1 1 1 1

The same results are obtained when the compounds of formula I are formulated in accordance with Examples F1, F2 and F4 to F8.

Example B2: Postemergence herbicidal action (contact herbicide)

Monocotyledonous and dicotyledonous test plants are grown in a greenhouse in plastics pots containing standard soil and are sprayed in the 4- to 6-leaf stage with an aqueous suspension of the test compounds of formula I prepared from a 25 % wettable powder (Example F3, b)), corresponding to a rate of application of 2 kg a.i./ha (5001 water/ha). The plants are then grown on in the greenhouse under optimum conditions. About 18 days later, the test is evaluated using a scale of nine ratings (1 = total damage, 9 = no action). Ratings of from 1 to 4 (especially from 1 to 3) indicate good to very good herbicidal action.

In this test too, the compounds of formula I according to the examples in Tables 1 to 11 exhibit pronounced herbicidal activity.

An example of the good herbicidal activity of the compounds of formula I is given in Table B2. Table B2: Postemergence action

Test plant: Setaria Sinapis Solanum Stellaria

Compound no.

1.027 1 1 1 1

Claims

What is claimed is:

1. A compound of formula I

wherein

R₁ is halogen;

R₅ is hydrogen, C₁-C₆alkyl, C₁-C₈haloalkyl, C₁-C₄alkoxy-C₁-C₄alkyl, C₁-C₁₀alkylthio- C₁-C₄alkyl, C₁-C₄alkylamino-C₁-C₄alkyl, di-C₁-C₄alkylamino-C₁-C₄alkyl, cyano-C₁-C₈- alkyl, C₃-C₈alkenyl, C₃-C₈haloalkenyl, C₃-C₈alkynyl, C₃-C₆cycloalkyl, oxetanyl, C₃-C₇- halocycloalkyl, C₃-C₇cycloalkyl-C₁-C₄alkyl, phenyl-C₁-C₃alkyl that is unsubstituted or substituted in the phenyl ring by 1, 2 or 3 identical or different substituents selected from halogen, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy and C₁-C₄haloalkoxy, or R₅ is an alkali metal, alkaline earth metal or ammonium ion, or is the group -N=C(CH₃)₂,

-CH₂-O-N=C(CH₃)₂ or -CH₂CH₂-O-N=C(CH₃)₂;

X is oxygen or sulfur;

A is C₁-C₄alkylene;

R₇ is hydrogen, C₁-C₈alkyl, C₁-C₃haloalkyl, C₁-C₄alkoxy, C₁-C₄alkoxy-C₁-C₄alkyl,

C₃-C₆alkenyl, C₃-C₆alkynyl, C₃-C₈cycloalkyl, hydroxy-C₁-C₄alkyl or cyano-C₁-C₄alkyl; R₈ is hydrogen, C₁-C₆alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy-C₁-C₄alkyl, hydroxy-C₁-C₄- alkyl, C₃-C₆alkenyl, phenyl or phenyl-C₁-C₃alkyl, the phenyl ring being unsubstituted or mono-, di- or tri-substituted by halogen, C₁-C₄alkyl, C₁-C₄haloalkyl, C₁-C₄alkoxy or by C₁-C₄haloalkoxy; or

Z is oxygen or sulfur;

n is 3, 4 or 5; and

n₁ is 0, 1, 2 or 3,

or a salt of such a compound.

2. A compound according to claim 1, wherein n is 3 or 4.

3. A compound according to claim 2, wherein n is 4.

4. A compound according to claim 1, wherein n₁ is 0, 1 or 2 and R is C₁-C₃alkyl.

5. A compound according to claim 1, wherein R₄ is the group -X-R₅.

6. A compound according to claim 5, wherein X is oxygen.

7. A compound according to claim 5, wherein R₅ is C₁-C₆alkyl.

8. A compound according to claim 1, wherein R₂ and R₃ are methyl.

9. A compound according to claim 1, wherein n₁ is 0, 1 or 2; R is methyl; R₁ is chlorine or bromine; R₂ and R₃ are methyl; R₄ is the group -X-R₅; R₅ is C₁-C₆alkyl; and X and Z are oxygen.

10. A compound according to claim 1, wherein R₄ is the group -X-A-R₆.

11. A compound according to claim 10, wherein X is oxygen and A is a C₁- or C₂- alkylene bridge .

12. A compound according to claim 1, wherein n₁ is 0, 1 or 2; R is methyl; R₁ is chlorine or bromine; R₂ and R₃ are methyl; R₄ is the group -X-A-R₆; and X and Z are oxygen.

13. A compound according to claim 1, wherein R₄ is the group

14. A compound according to claim 1, wherein n₂ is 0, 1 or 2; R is methyl; R₁ is chlorine or bromine; R₂ and R₃ are methyl; R₄ is the group ; and Z is oxygen.

15. A compound according to claim 1 of formula Ia

wherein

R₂ is chlorine or bromine;

R₅ is hydrogen, C₁-C₅alkyl, C₂chloroalkyl, C₁- or C₂-alkoxy-C₂- or -C₃-alkyl, C₁-C₅alkylthio-C₂- or -C₃-alkyl, di-C₁- or -C₂-alkylamino-C₃ alkyl, cyano-C₁- or -C₂-alkyl, C₃- or

C₄-alkenyl, C₃chloroalkenyl, C₃- or C₄-alkynyl, C₅- or C₆-cycloalkyl, C₃- or C₅-cycloalkyl-C₁- or -C₂-alkyl, phenyl-C₁- or -C₂-alkyl that is unsubstituted or monosubstituted in the phenyl ring by chlorine or by methyl, or R₅ is the group -N=C(CH₃)₂ or

X is oxygen or sulfur.

16. A compound according to claim 1 of formula Ib

wherein

R₁ is chlorine or bromine;

X is oxygen;

A is C₁- or C₂-alkylene; and

R₆ is 2-furyl, 2-tetrahydrofuryl, 2-thienyl, 2-, 3- or 4-pyridyl, 4-methyl-5-thiazolyl, pyrrolidin-2-on-1-yl, N-morpholinyl, N-piperidyl, 1-imidazolyl or 1-methyl-4-pyrazolyl.

17. A compound according to claim 1 of formula Ic

wherein

R₁ is chlorine or bromine;

R₇ is hydrogen, C₁-C₄alkyl, C₃alkenyl, methoxy, C₃-C₈cycloalkyl or cyano- or hydroxy- C₂alkyl; and

R₈ is hydrogen, C₁-C₅alkyl, C₂chloroalkyl, methoxy-C₂alkyl, hydroxy-C₂alkyl, C₃- or

18. A compound according to claim 1 of formula Id

wherein

R is hydrogen or methyl;

R₁ is chlorine;

X is oxygen or sulfur; and

R₅ is hydrogen, C₁-C₃alkyl, C₃- or C₄-alkenyl, C₃chloroalkenyl, C₃alkynyl, C₁- or C₂- alkoxy-C₂alkyl or C₁- or C₂-alkylthio-C₃alkyl.

19. A compound according to claim 1 of formula le

o

wherein

R₁ is chlorine;

X is oxygen; and

20. A compound according to claim 1 of formula If

wherein

R₁ is chlorine or bromine;

X is oxygen;

A is C₁- or C₂-alkylene; and

N-moφholinyl.

21. A compound according to claim 1 of formula lg

o

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

R₇ is hydrogen, C₁-C₄alkyl, C₃alkenyl, methoxy or C₃cycloalkyl; and

22. A compound according to claim 1 of formula Ih

wherein

R₁ is chlorine;

R₇ is hydrogen, methyl, methoxy, C₃alkenyl or C₃cycloalkyl; and

R₈ is hydrogen, C₁-C₄alkyl or C₃- or C₄-alkenyl; or

23. A compound according to claim 1 of formula Ii

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

X is oxygen or sulfur; and

R₅ is hydrogen, C₁-C₃alkyl, methoxy-C₂alkyl, C₂- or C₃-alkylthio-C₃alkyl, C₃- or C₄- alkenyl, C₃chloroalkenyl, C₃alkynyl, C₆cycloalkyl, C₃cycloalkyl-C₂alkyl, phenyl-C₁- or

-C₂-alkyl or the group -N=C(CH₃)₂.

24. A compound according to claim 1 of formula Ij

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

X is oxygen;

A is C₁- or C₂-alkylene; and

4-pyridyl or 4-methyl-5-thiazolyl.

25. A compound according to claim 1 of formula Ik

wherein

R is hydrogen or methyl;

R₁ is chlorine or bromine;

R₇ is hydrogen, methyl, methoxy, C₃cycloalkyl or C₃alkenyl; and

26. 2-Methyl-2-[2-cWoro-5-[(tetrahydro-3-oxo-1H,3H-[1,3,4]thiadiazolo[3,4-a]pyridazin- 1-yHdene)amino]-benzoyloxy]-propionic acid 2-chloro-2-propenyl ester according to claim 1.

27. A process for the preparation of a compound of formula I according to claim 1, which process comprises reacting a compound of formula II

with thiophosgene to form the compound of formula III

the radicals R₁ to R₄ in the compounds of formulae II and III being as defined in claim 1, and converting the compound of formula III with a compound of formula V

wherein R, n and n₁ are as defined in claim 1, into the compound of formula IV

CZCl₂ (NI), wherein Z is oxygen or sulfur, if desired in the presence of a base.

28. A compound of formula XI

wherein R₁ to R₃, R₅ and X are as defined in claim 1.

29. A compound of formula XVI

wherein R₁ to R₃, R₆, X and A are as defined in claim 1.

30. A compound of formula XVIII

wherein R₁ to R₃, R₇ and R₈ are as defined in claim 1.

31. A compound of formula II

wherein R₁ to R₄ are as defined in claim 1.

32. A compound of formula III

wherein R₁ to R₄ are as defined in claim 1.

33. A compound of formula IV

wherein R, R₁ to R₄, n and n₁ are as defined in claim 1.

34. A herbicidal and plant-growth-inhibiting composition which comprises one or more compounds of formula I according to claim 1 and solid or liquid formulation adjuvants.

35. A composition according to claim 34, which comprises from 0.1 % to 95 % of a compound of formula I according to claim 1.

36. A method of controlling undesired plant growth, which method comprises applying an effective amount of a compound of formula I according to claim 1, or of a composition comprising such a compound, to the plant or the locus thereof.

37. A method according to claim 36, wherein from 0.001 to 2 kg of active ingredient are applied per hectare.

38. A method of inhibiting plant growth, which method comprises applying an effective amount of a compound of formula I according to claim 1, or of a composition comprising such a compound, to the plant or the locus thereof.

39. The use of a composition according to claim 34 in the selective control of weeds in crops of useful plants.