CA2050197A1 - Heterocyclic compounds - Google Patents

Abstract

Heterocyclic compounds Abstract The invention relates to novel compounds of the formula I
wherein R2, R2, R3, R4 and R5 have the meanings given in the description, to enol ethers and salts thereof and their preparation, to weed control compositions that comprise such compounds as active ingredients, and to the use of the compounds or compositions to control weeds. The invention relates also to certain novel starting materials and to the preparation thereof.

Description

P~1/5-18413/A/~AG 2076 Heterocyclic compounds The present invention relates to heterocyclic compounds, that is to 3-aryluracils of the general forrnula ~,N~COOR2 R CN

.
wherem Rl is hydrogen, Cl-C4aL~cyl, C3-C4aLIcenyl, C3-C4aLlcynyl, C2-C6aL~coxyaLkyl or Cl-C4haloalkyl, R2 is hydrogen, Cl-C6alkyl, C2-C6alkoxyaL~cyl, C4-C7cycloaLkenyl-Cl-C4aLlcyl that is unsubstituted or ring-substituted by from 1 to 3 Cl-C3alkyl groups, C3-C4aL~cenyl, C4-C7cycloaLtcenyl-C3-CsaL~cenyl that is unsubstituted or ring- substituted by from 1 to 3 Cl-C3aL~cyl groups, aryl-C3-C5aLkenyl, C3-C4aL~cynyl, C4-C7cycloaLtcenyl-C3 CsaLlcynyl that is unsubstituted or ring-substituted by from 1 to 3 Cl-C3aLkyl groups, or aryl-C3-Cs-aLIcynyl, R3 is hydrogen or halogen, R4 is hydrogen, halogen or Cl-C4a1kyl and Rs is Cl-C4aL~yl or Cl-C4haloaLkyl, or R4 and Rs together are tri- or tetra-methylene, with the proviso that, when Rs is Cl-C4haloaLIcyl, Rl is other than Cl-C4haloalkyl and R2 is other than hydrogen~

and the corresponding enol ethers of those compounds of ~ormula I wherein Rl is other than hydrogen or Cl-C4haloaLIcyl, and salts of those compounds of forrnula I wherein R
and/or R2 are (is) hydrogen.
There are thus to be understood by the above-mentioned enol ethers the compounds of the formula R5~ N~ORl ~ COOR2 Ia R3~ CN

wherein Rl' is Cl-C4alkyl, C3-C4alkenyl, C3-C4alkynyl or C2-C6alkoxyalkyl.

The compounds of the invention, that is to say the compounds of -formula I and the enol ethers and salts thereof, are herbicidally active and are suitable as active ingredients of weed control compositions. The invention thus also includes weed control compositions that contain compounds of the invendon as active ingredients, processes for the preparation of those-compounds and the use of the compounds and compositions forcontrolling weeds.

In the above formula I, "halogen" includes fluorine, chlorine, bromine and iodine. The alkyl, alkenyl and alkynyl radicals may be straight-chain or branched, this applying also to the or each aL~cyl, alkenyl or alkynyl moiety of the vaIious alkyl-, alkenyl- oraLtcynyl-containing groups, respectively, such as, for exarnple, "C4-C7cycloalkenyl-C3-Cs-alkenyl that is unsubstitueed or ring-substituted by from 1 to 3 Cl-C3alkyl groups". A halo-alkyl group may contain one or more identical or different halogen atoms. Aryl (of the aryl-C3-Csalkenyl and aryl-C3-Csalkynyl groups) is especially phenyl, it being possible for such groups to be substituted by from 1 to 3 halogen atoms, Cl-C3alkyl, Cl-C3halo-alkyl, Cl-C3aLIcoxy, Cl-C3alkylthio, C2-C4alkanoyl, C2-C4alkoxycarbonyl, Cl-C3aLIcyl-sulfonyl, nitro and/or cyano. The fused rings forrned by R4 and R~ (R4 and Rs together are tri- or tetra-methylene) are represented by the following par~al structures:

The salts of the compounds of folmula I are especially aLIcali 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 ~mmonium salts, e.g. triethylammonium and methylammonium salts, and also salts with other organic bases, e.g. with pyridine.

The possible presence of at least one asymmetric carbon atom in the compounds offormula I means that the compounds may occur in optically isomeric forms. As a result o~
the possible presence of an aliphatic C=C double bond, geometric isomerism may also occur. Formula I shall include all those possible isomeric forms and also mixtures thereof.

If Rl or R2 is alkenyl or ,llkynyl, then that group is preferably allyl or 3-buten-2-yl, or propargyl or 3-butyn-2-yl, respectively. In general, a halogen atom that may be present is preferably fluorine.

Independently of one another, Rl is preferably Cl-C4alkyl, especially methyl; R2 is preferably C1-C6aLkyl, C~-C6alkoxyalkyl, C3-C4all~enyl or C3-~4alkynyl; R3 is preferably hydrogen or fluorine; R4 is preferably hydrogen, methyl or fluorine; and Rs is preferably Cl-C4alkyl or trifluoromethyl. Likewise, R4 und Rs together are preferably tri- or tetra-methylene.

Especially preferred compounds of formula I are:
2-cyano-5-(1 ,2,4,5,6,7-hexahydro- 1 -methyl-2,4-dioxo-3H-cyclopenta[d]pyrimidin-3-yl)-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5- ( 1,2,4,5 ,6,7-hexahydro- 1 -methyl-2,4-dioxo-3H-cyclopenta[d] -pyrimidin-3-yl)-benzoic acid isopropyl ester, 2-cyano-5-[i,4,5,6,7,8-hexahydro-1-methyl-2,4-dioxo-3(2H)-quinazolinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-rl ,4,5,6,7,8-hexahydro-1-methyl-2,4-dioxo-3(2H)-quinazolinyl]-benzoic acid isopropyl çster, 2-cyano-5- ~3,~-dihydro-3,4-dimethyl-2,6-dioxo- 1 (2~I)-pyr~midinyl]-4-fluoroben~oic acid isopropyl ester, 2-cyano-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-(1(2H)-pyrimidinyl]-benzoic acid isopropyl ester and 2-cyano-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-1 (2~I)-pyrimidinyl]-4-fluorobenzoic acid isopropyl ester, and the corresponding methyl, ethyl, n-propyl, n-butyl, sec-butyl, isobutyl, tert-butyl, methoxymethyl, 1-methoxyethyl, 2-methoxyethyl, 1-methoxypropyl, 1-ethoxyethyl, .

2~ 7 2-methoxy-1-rnethyiethyl, allyl, 1-methyl-2-propenyl, 1-ethyl-2-propenyl, 2-butenyl, propargyl, 2-butynyl, 1-methyl-2-propynyl- and 1-ethyl-2-propynyl esters of the above compounds.

Further examples of compounds of formula I are:

2-cyano-4-fluoro-S-[S-chloro-3,6-dihydIo-4-methyl-2,6-dioxo-1(2~I)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5- [5-chloro-3,6-dihydro-3,4-dimethyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluo,ro-5-~3,6-dihydro-4-trifluoromethyl-2,6-dioxo- 1 (2H)-pyrimidinyl~-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5- [4-ethyl-3,6-dihydro-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid iso propyl ester, 2-cyano-4-fluoro-5-E4-ethyl-3,6-dihydro-3-methyl-2,6-dioxo-1 (2H)-pyrimidinyl]-benzoic acid isopropyl ester;
2-cyano-4-fluoro-5-[3,4-diethyl-3,6-dihydro-2,6-dioxo-1(2H~-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-~4-ethyl-3,6-dihydro-5-methyl-2,6-dioxo-1(2H~-pyrin~.idinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-~4-ethyl-3,6-dihydro-3,5-dimethyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[3,4-diethyl-3,6-dihydro-5-methyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-~3,6-dihydro-4-isopropyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid isopropylester, 2-cyano-4-fluoro-5-[3,6-dihydro-4-isopropyl-3-methyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[3-ethyl-3,6-dihydro-4-isopropyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[3,6-dihydro-4-isopropyl-5-methyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[3,6-dihydro-3,5-dimethyl-4-isopropyl-2,6-dioxo- 1 (2~)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5- [3-ethyl-3,6-dihydro-4-isopropyl-5-methyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid isopropyl ester, 4-chloro-2-cyano-5-(1 ,2,4,5,6,7-hexahydro-1-methyl-2,4-dioxo-3H-cyclopenta[d]-pyrimidin-3-yl)-benzoic acid isopropyl ester, 4-bromo-2-cyano-5-(1,2,4,5,6,7-hexahydro-1-methyl-2,4-dioxo-3H-cyclopenta[d]-pyrimidin-3-yl~-benzoic acid isopropyl ester, 2-cyano-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-1(2H)-pylimidinyl]-benzoic acid methyl ester and the coIresponding ethyl, n-propyl, n-butyl, sec-butylj isobutyl, tert-butyl, methoxymethyl, l-methoxyethyl, 2-methoxyethyl, l-methoxypropyl, l-ethoxy-ethyl, 2-methoxy-1-methyletllyl, allyl, 1-methyl-2-propenyl, 1-ethyl-2-propenyl,2-butenyl, propargyl, 2-butynyl, 1-methyl-2-propynyl and 1-ethyl-2-propynyl esters of that compound, 2-cyano-4-fluoro-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-benzoic acid methyl ester and the corresponding ethyl, n-propyl, n-butyl, sec-butyl, isobutyl, tert-butyl, methoxymethyl, l-methoxyethyl, 2-methoxyethyl, l-methoxypropyl, l:ethoxyethyl, 2-methoxy-1-methylethyl, allyl, 1-methyl-2-propenyl, l-ethyl-2-propenyl, 2-butenyl, propargyl, 2-butynyl, 1-methyl-2-propynyl and 1-ethyl-2-propynyl esters of that compound.

The process according to the invention for the preparation of compounds of formula I and their enol ethers and salts comprises a) for the preparation of those compounds of formula I wherein Rl is hydrogen and R2 is other than hydrogen and R4 is other than chlorine, bromine or iodine and, if desired, metal salts of those compounds, subjecting to cyclisation, under basic conditions, a compound of the general formula H

Rs~ N ~0 ,J, H-N II
R4~ C-OR6 \
o \~, COOR2 R3~CN

wherein R3 and Rs are as defined above, R2' has the meaning given above for R2 with the exception of hydrogen, R4' iS hydrogen, fluorine or Cl-C4alkyl or, together with R5, is tri-or tetra-methylene, and R6 is lower alkyl, preferably Cl-C4alkyl, and, if desired, converting a possibly resulting metal salt forrn of the uracil derivative into the corres-ponding acid form (Rl = hydrogen) by treatment with an acid, b) for the preparation of those compounds of formula I wherein R1 is hydrogen and R2 is other than hydrogen, R4 is other than chlorine, bromine or iodine and Rs is other than Cl-C4haloalkyl and, if desired, metal salts of those compounds, subjecting to cyclisation, under basic conditions, a compound of the general formula R5' ~N~ ~;o J~HN~COOR~' III

R CN
wherein R2' and R3 are as defined above, R4' is hydrogen, fluorine or Cl-C4alkyl or, together with Rs~, is tri- or tetra-methylene, Rs~ is Cl-C4alkyl or, together with R4', is tri-or tetra-methylene, and R7 is lower alkyl, preferably Cl-C4alkyl, and, if desired, converting a possibly resulting metal salt of the uracil derivative of formula I into the acid form (R1 = hydrogen) by treatment with an acid, c) for the preparation of those compounds of formula I wherein Rl is C1-C4alkyl,C3-C4aL~cenyl, C3-C4alkynyl, C2-C~alkoxyalkyl or Cl-C4haloalkyl, subjecting a uracil derivative of the general formula H
R5 N ~O
COOR2 1' R CN

7 2~
wherein R2, R3, R4 and Rs are as defined above, to alkylation with a corresponding alkylating agent comprising a Cl-C4alkyl, C3-C4-alkenyl, C3-C4alkynyl, C2-C6aLkoxyalkyl or Cl-C4haloalkyl group, d) for the preparation of all compounds of forrnula I and the enol ethers, treating a uracil derivative of the general formula ~R1 R~COORz IV

wherein Hall is halogen, preferably chlorine or bromine, and Rl, R2, R3, R4 und Rs are as defined above, or the corresponding enol ether, with a metal cyanide, e) for the preparation of those compounds of formula I wherein R2 is hydrogen and Rs is other than Cl-C4haloalkyl, and the enol ethers thereof, hydrolysing a benzoic acid ester of the general formula R5~ N ~;0 COOR2' 1"

R CN

wherein Rl, R2', R3, R4 and Rs' are as defined above, to form the corresponding benzoic acid, f) for the preparation of those compounds of formula I wherein Rl and R2 are each other than hydrogen and Rs is other than Cl-C4haloalkyl, and the corresponding enol ethers, 8 2~

esterifying a benzoic acid of the general forrnula "
R5' N ~O
~3~COOH 1"' wherein Rl" is Cl-C4alkyl, C3-C4alkenyl, C3-C4alkynyl, C2-C6alkoxyalkyl or Cl-C4halo-alkyl and R3, R4 and Rs' are as defined above, or the corresponding enol ether, it being possible for the benzoic acid or its enol ether to be in the form of a reactive derivative, with a hydroxy compound of the general formula HO-R2' V
wherein R2' is as defined above, or with a reactive derivative of that hydroxy compound, g) for the preparation of those compounds of formula I wherein Rl and R2 are each other than hydrogen, and the enol ethers thereof, subjecting a benzoic acid ester of the general formula Rl"

~a~COOR2" 1""

wherein Rl", R3, R4 and R5 are as defined above and R2" is Cl-C6aLkyl, C3-Cqalkenyl, C3-C4alkynyl or C2-C6alkoxyaLkyl, or the corresponding enol ether, to a transesterification reaction with a hydroxy compound of the above formula V, the reagent V having a higher boiling point than the respective alkanol, alkenol or alkynol R2"0H, h) for the preparation of those compounds of formula I wherein R4 is chlorine, bromine or iodine, and the corresponding enol ethers, chlorinating, brominating or iodinating a uracil derivative of the general forrnula Rl R5~ N ~oO
J~N~}~COOR2 I""' R CN
wherein Rl, R2, R3 and Rs are as defined above, or the corresponding enol ether, i) for the preparation of the enol ethers of the compounds of formula I, treating a uracil derivative of the general formula R~ N~ Hal2 R3~CN

wherein R2, R3, R4 and Rs are as defined above, and Hal2 is chlorine or bromine, with an alkanol, alkenol or alkynol Rl'OH in the presence of an organic base, or widl the corresponding alcoholate, alkenolate or alkynolate, respectively, of the general formula Rl'o~)M~3 VII
wherein Rl' is as defined above and M~33 is an equivalent of a metal ion and, if desired, converting a resulting compound of formula I wherein Rl and/or R2 are (is) hydrogen into a salt.

The cyclisation according to process variant a) or b) can advantageously be carried out by treating the compound of formula II or III in an inert protic organic solvent, such as an alcohol, e.g. methanol, ethanol or isopropanol; in an inert aprotic organic solvent, such as an aliphatic or cyclic ether, e.g. 1,2-dimethoxyethane, tetrahydrofuran or dioxane, or an aromatic compound, e.g. benzene or toluene; in an inert aprotic polar organic solvent, e.g.
dimethylformarnide or dimethyl sulfoxide, it being possible, if desired, for such solvents to be used in a two-phase mixture with a hydrocarbon, e~g. n-hexane or toluene; or in water, with a base, at temperatures from -78C to the reflux temperature of the reaction mixture. Suitable bases are preferably sodium alcoholates, alkali metal hydraxides, especially sodium hydroxide and potassium hydroxide, alkali metal carbonates9 especially sodium carbonate and potassium carbonate, and sodium hydride. If an alkanol is used as solvent, then that solvent advantageously corresponds to the respective hydroxy compound E~2'-OH; by this means undesired competing trans-esterification reactions are avoided. If sodium hydride is used as base, th~ solvent is preferably an aliphatic or cyclic ether, dimethylfonnamide or dimethyl sulfoxide, it being possible for any of those solvents to be used in admixture with toluene.

When the cyclisation is complete, if one of the above-mentioned bases or the like is used, the product is in the form of the corresponding alkali metal salt. This can be isolated and purified in a manner known E~r se, or the mixture can be acidified in order to isolate the respective cornpound of formula I itself. For that purpose preferably a minera~ acid, such as hydrochloric acid, or a strong organic acid, such as acetic acid ~r p-toluenesul~onic acid, is used.

In process variant c), the tenn "aLcylation" denotes the substitution of the hydrogen atom of the Nl atom of ~he uracil nucleus by a Cl-C4aLcyl, C3-C4alkenyl, C3-C4aLlcynyl, C2-C6alkoxyaLcyl or Cl-C4haloaLcyl group. There is advantageously used as aLkylating agent a Cl-C4aLcyl, C3-C4alkenyl, C3-C4aL~ynyl or C2-C6aL'coxyaLcyl halide, especially the appropriate chloride or bromide, or sulfate, or a polyhalogenated Cl-C4alkane, such as, e.g., chlorodifluoromethane, or a mono- or poly-halogenated alkene, such as, e.g., tetra-fluoroethane.

The aL~cylation is advantageously carried out in the presence of an inert protic Grganic solvent, such as a lower aL~anol, for example ethanol, i~ desired in adrnixture with water;

an inert aprotic orgaDic solvent, such as an aliphatic or cyclic ether, e.g. 1,2-dimethoxy-ethane, tetrahydrofuran or dioxane; a ketone, e.g. acetone or butan-2-one; or an inert aprotic polar organic solvent, e.g. dimethylformamide, dimethyl sulfoxide or acetonitrile, and also in the presence of a base, such as sodium hydride, an alkali metal hyd}oxide, especially sodium or potassium hydroxide, an alkali metal alcoholate, especially sodium alcoholate, or an aL~ali metal carbonate or hydrogen carbonate, especially sodium carbonate, potassium carbonate, sodium hydrogen carbonate or potassium hydrogen carbonate, at temperatures from OC to the reflux temperature of the reaction mixture, preferably at room temperature or, in the case of substitution of the hydrogen atom of the Nl atom with a Cl-C4haloalkyl group, preferably at temperatur~s from 50C to 100C. In a preferred embodiment, the uracil derivative of formula I' is ~lrst of all treated with the base, such as sodium hydride, ethanolate or carbonate, in the solvent and, after a short reaction time, the halide is added in the same solvent. In a further embodiment, the uracil derivative I', together with a dialkyl sulfate, is reacted at reflux temperature in the presence of an alkali metal hydrogen carbonate, especially sodium or potassium hydrogen carbonate, in the solvent, e.g. acetone. The reaction is usually complete within a relatively short time or after a few hours, depending on the solvent used.

Process variant d) is an exchange reaction of the halogen substituent of the benzene nucleus. That halogen atom is thus replaced by the cyano group by means of the metal cyanide. The latter is especially a transition metal cyanide, preferably copper(I) cyanide.
The reaction is advantageously carried out in the presence of an aprodc polar solvent, such as an aL~ylnitrile, e.g. acetonitrile, propionitrile or butyronitrile; an aL~cylurea, e.g. tetra-methylurea; a dialkylarnide, e.g. dimethylformarnide; a dialkyl sulfoxide, e.g. dimethyl sulfoxide; N-methyl-2-pyrrolidone; 1,3-dirnethyl-imidazolidin-2-one; 1,3-dirnethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone; or hexamethylphosphoric acid triamide, atelevated temperatures, that is from 80C to 200C, preferably from 150C to 200C. In the starting material I", R4 is preferably hydrogen or fluorine.

The hydrolysis of the benzoic acid ester I" or the enol ether thereof according to process variant e,~ can be ca~ied out according to methods known ~ se, especially using an organic solvent in aqueous solution, such as an aqueous alkanol, e.g. ethanol, or an aliphatic or cyclic ether, e.g. 1,2-dimethoxyethane, tetrahydrofuran or dioxane, in aqueous solution, and an inorganic base, such as lithium, sodium or potassium hydroxide, ~r an alkaline earth metal hydroxide, e.g. magnesium or calcium hydroxide, at temperatures from 0C to 60C, preferably at room temperature.

.

- ~ 20 .

Process variant f) is an esteriFlcation of benzoic acid or the enol ether or a reactive derivative thereof, which can be carried out according to methods known ~ se. For example, a salt of a benzoic acid of formula I"' or of the corresponding enol ether is reacted with a halide, especially the chloride, bromide or iodide, or the sulfate? mesylate or tosylate of the hydroxy compound V in an inert diluent at temperatures from roomtemperature to 100C, e.g. at the reflux temperature of the reaction mixture, preferably in a temperature range from 40C to 70C. Suitable salts of the benzoic acid of formula I"' or of the corresponding enol ether are especia~ly alkali metal salts, e.g. the sodium, potassium or lithium salt, alkaline earth metal salts, e.g. the magnesium, calcium or barium salt, and salts with organic bases, such as tertiary amines, e.g. triethylamine, 1,5-diaza-bicyclo[4.3.0]non-5-ene, 1,~-diaza-bicyclo[5.4.0]undec-7-ene.and 1,4-diaza-bicyclo[2.2.2]octane, with the alkali metal salts, especially the sodium salt and the potassium salt, being preferred. The diluents that can be used are preferably inert organic solvents, such as lower alkanols, e.g. ethanol, aliphatic and cyclic ethers, e.g. diethyl ether, tetrahydrofuran and dioxane, ketones, e.g. acetone and 2-butanone, dimethylforrnarnide, dimethyl sulfoxide, acetoni~ile and hexamethylphosphoric acid triamide. The salt can be produced in situ by reacting the acid with a suitable inorganic base, e.g. an alkali metal or alkaline earth metal carbonate, hydrogen carbonate, hydroxide or hydride, or organic base, to -form the salt, which can then be reacted with the second reactant in the same reaction medium.

When an acid halide of the benzoic acid of formula I"' or of the correspondin~ enol ether is used as reactive derivative, it is advantageously reacted with the hydroxy compound of forrnula V in an inert organic solvent, such as an aliphatic or cyclic ether, e.g. diethyl et'ner, 1,2-dimethoxyethane, tetrahydrofuran or dioxane, an aliphatic or aromatic hydro-carbon, e.g. n-hexane, benzene or toluene, or a halogenated, especially chlorinated, hydrocarbon, e.g. methylene chloride, chloroforrn or carbon tetrachloride, at temperatures of approximately from -20C to 100C, preferably from 0C to 50C. ~n addition, the reaction is advantageously carried out in the presence of an acid-binding agent, such as an organic base, e.g. triethylamine, pyridine, 4-dimethylaminopyridine, 1,5-diaza-bicyclo-[4.3.0]non 5-ene, 1,~-diaza-bicyclo[5.4.0]undec-7-ene or 1,4-diaza-bicyclo[2.2.2]octane.
The acid halide is preferably the acid chloride.

Other suitable reactive derivatives of the benzoic acid of formula I"' vr of thecorresponding enol ether are the corresponding O-acyl-1,3-dicyclohexylisourea and the corresponding N-acylimidazole or acid anhydride. Such derivatives can, like the acid halide, be reacted with the hydroxy compounds of forrnula V in order to obtain the desired benzoic acid esters. In those cases, however, the use of an acid-binding agent is not necessary.

The reaction according to process variant g) can advantageously be carried out by heating the benzoic acid ester of formula I"" or its enol ether in excess hydroxy compound of formula V in the presence of a weakly basic catalyst, such as sodium cyanide or preferably tetraisopropyl or tetrapropyl orthotitanate, preferably at the reflux temperature of the reaction mixture. In the course of the reaction the radical R2" of the benzoic acid ester I""
is replaced by the group R2' of the hydroxy compound V, the lower boiling alkanol, alkenol or alkynol R2"OH being freed and removed from the reaction mixture.

The chlorination or bromination according to process variant h) is advantageously carried out using elemental chlorine or sulfuryl chloride, or elemental bromine or sulfuryl bromide, respectiveiy, in the presence of an inert organic solvent, such as acetic acid or a chlorinated aliphatic hydrocarbon, e.g. methylene chloride, chloroform or carbon tetra-chloride, and in a temperature range from 0C to 60C, preferably at room temperature. In addition, the reaction can be carried out with the assistance of an acid-binding agent, sodium acetate and tertiary amines, such as triethylamine, dimethylaniline and pyridine, being especially preferred acid-binding agents for that purpose.

The iodination according to that process variant is advantageously carried out using elemental iodine as iodinating agent and of a low-boiling aliphatic carboxylic acid, such as acetic acid, as solvent, at temperatures from approximately 0C to approximately 110~, preferably at room temperature. In addition, it has proved advantageous to caIry out the reaction in the presence of an acid, such as fuming nitric acid. When the reaction is complete, saturated aqueous sodium hydrogen sulfite solution can be added in order to remove excess lodlne.

In process variant i), the term "metal ion" indicates especially an aL~cali metal ion, e.g. the sodium or potassium ion, or an alkaline earth metal ion, e.g. the calcium or magnesium ion. ~he sodium ion is the preferred metal ion. If the aL~anol, alkenol or aL~cynol Rl'OH is used, then the suitable organic base is especially pyridine.

The reaction is advantageously carried out in an excess of the corresponding alcohol - , 2~ 7 R~'OH as diluent, and at temperatures from 0C to 50C, preferably at room temperature.

If they cannot be prepared directly by the above-described cyclisation canied out under basic conditions, the desired salts of the compounds of formula I in which Rl is hydrogen can alte~natively be prepared from those compounds I in a manner known ~ se, forexample by dissolving the compound of formula I in a solution of an appropriate organic or inorganic base. The salt formation is usually effected within a short time at room temperature. In one embodiment, the sodium salt is prepared by dissolving the uracil derivative I in aqueous sodium hydroxide solution at room temperature, using equivalent amounts of the uracil derivative and of sodium hydroxide. The solid salt can then be isolated by precipitation with a suitable inert solvent or by evaporating off the solvent.
Another embodiment comprises introducing an aqueous solution of an alkali metal salt of the uracil derivative I into an aqueous solution of salt that has a metal ion other than an alkali metal ion, the second metal salt of ~he uracil derivative being produced. This embodiment is generally used to prepare uracil metal salts that are insoluble in water.

The compounds of formula I, enol ethers and salts obtained can be isolated and purified according to methods known ~ se. Also familiar to the person skilled in the art is the sequence in which possible combinations of process variants c) to h) are advantageously to be carried out so as to avoid possible undesired competing reactions.

If no specific synthesis for the isolation of pure isomers is carried out, the product may be obtained in the form of a mixture of two or more isomers. The isomers can be separated according to methods known ~ se. If desired, for example, pure optically active isomers can also be produced by synthesis from corresponding optically active starting materials.

The starting materials of formula II, which are novel, can be prepaled in a manner known ~ se, e.g. in accordance with the following Reaction Schemes 1 ~Methods aa), bb) and cc)]:

Reaction Schemes 1 z~

R5 ~0 H2N ~0 6 ~COOR2 VIII IX

R5 ~N~O
R4 ICI _OHR6N X COOR2 R4 XGOR6 ~XCOOR2 X XI

R5~N~O
R C OR ~XCOOR2 II

R5~ ~R8 H2N ~O

CC) R ~ C OR HN~COOR2' XII ~

R5' 1~O

R4~ ~C-OR6 COOR2' O R3~ CN

II"

In the above reaction schemes, R2~, R3, R4~, Rs, Rs~ and R6 have the meanings given hereinbefore; R4~ is hydrogen or Cl-C4alkyl or, together with Rs~, is tri- or tetra-methylene; and R8 is lower aL~cyl, preferably Cl-C4alkyl.

Method aa) is advantageously caIIied out by reacting the compounds of fonnulae VIII and IX with each other in a substantially anhydrous diluent in the presence of an acid catalyst at elevated tenmperature. Suitable diluents are especially organic solvents that form azeotropes with water, such as aromatic compounds, e.g. benzene, toluene and xylenes;
halogena~ed hydrocarbons, such as methylene chloride, chloroform, carbon tetrachloride and chlorobenzene; and aliphat;c and cyclic ethers, such as 1,2-dimethoxyethane,tetrahydrofuran and dioxane, and suitable acidic catalysts are especially strong mineral acids, such as sulfuric acid and hydrochloric acid; organic acids, such as p-toluenesulfonic acid; phosphorus-containing acids, such as orthophosphoric acid and polyphosphoric acid;
and acidic cation exchangers, such as "Amberlyst 15" (Fluka). The reaction is generally ~ ; ~

carried out in a temperature range from approximately 70C to 120C, preferably at the reflux temperature of the reaction mixture. Under those reaction conditions the desired rapid removal of the water forrned during the reaction is achieved.

The reaction according to Method bb) is advantageously carried out in the presence of a substantially anhydrous aprotic organic solvent, such as an aliphatic or cyclic ether, e.g.
diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran or dioxane, an aliphatic or aromatic hydrocarbon, e.g. n-hexane, benzene, toluene or a xylene; or a halogenated, aliphatic hydrocarbon, e.g. methylene chloride, chloroform, carbon tetrachloride or 1,2-dichloroethane; and also where appropriate in the presence of a base, especially an organic tertiary base, such as triethylamine or pyridine, it being possible for the latter to be used both as solvent and base, or a metal hydride, such as sodium or potassium hydride.
The reaction temperatures are preferably in the range of approximately from -80C to 50C, temperatures of from -30C to room temperature being especially preferred.
The reaction according to Method cc) is advantageously carried out in an inert water-miscible organic solvent, such as an aliphatic or cyclic ether, e.g.
1,2-dimethoxyethane, tetrahydrofuran or dioxane, or a lower alkanol, such as ethanol, at temperatures from 50C to 100C, preferably at the reflux temperature of the reaction mixture, or in an aromatic solvent, such as benzene, toluene or a xylene, in the presence of an acidic catalyst, such as hydrochloric acid or p-toluenesulfonic acid, at temperatures from 50C to 100C, preferably from 60C to 80C.

The starting materials of formula III are also novel and can be prepared in a manner known ~ se, e.g. in accordance with the following ~eaction Schemes 2 ~Iethods dd), ee) and ff)]:

Reaction Schemes 2 Rg-CI I = C _ o H2N ~\~ GOOR2' dd) R4-"CH- C=O R3 J~CN

XIII XIV

R9-CH2 ~ ~0 R"'lH N COOR2' CN

XV

o~o/l' R3 COOR2' ~VI XIV

R" O

2 ~C/ COOR2' o R3 )~CN

XVII

R' H2N COOR2' R4' C--6 ~ CN
o VIII XIV

., ~ j.

~C~
H
4 ~ C/ \~ COOR2' R3~ ~CN

XVIII

XV/XVIVXVIII + H2NCOOR7 1~ m XIX

In the above Reaction Schemes, R2~, R3, R4~, Rs~, R6 and X have the meanings givenhereinbefore; R4~ is hydrogen or Cl-C4alkyl; R5~ is Cl-C4aL~cyl; and R~ is hydrogen or Cl-C3alkyl.

The reaction of the amine of forrnula XIV with the diketene of formula XIII according to Method dd) is advantageously carried out in an anhydrous inert aprotic solvent, such as a halogenated hydrocarbon, e.g. methylene chloride, chloroforrn, carbon tetrachloride or chlorobenzene, an aromatic hydrocarbon, e.g. benzene, toluene or a xylene, or an aliphatic or cyclic ether, e.g. diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran or dioxane, in the presence of a basic catalyst, such as 4-pyrrolidinopyridine~ 4-dimethylaminopyridine, 1,4-diazabicyclo[2.2.2]octane, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene or diethylarnine. Since the reaction is exotherrnic, it is generally carried out in a temperature range from -10C to 50C, preferably at room temperature.

The reaction of the compounds of formulae XVI and XIV with each other in accordance with Method ee) is advantageously carried out in an anhydrous inert aprotic solvent at temperatures from approximately 70C to l40C, preferably from 100C to 120C. There are sui~able as such solvents especially aromatic compounds, e.g. benzene, toluene and xylenes; halogenated hydrocarbons, e.g. carbon tetrachloride, trichloroethane, tetrachloroethane and chlorobenzene; and aliphatic and cyclic etheTs, e.g. dibutyl ether, : .

.
1,2-dimethoxyethane, tetrahydrofuran and dioxane.

The reaction according to Method ff) is an aminolysis, which is advan~ageously carried out in an anhydrous solvent, or without solvent [see, for example, ~. Soc. Dyes Col. 42, 81 (1926), Ber. 64, 970 (1931) and J.A.C.S. 70, 2402 (1948)] at elevated temperature.
Suitable solvents are especially inert aprotic solvents, such as unsubstituted or halogenated aromatic compounds, e.g. toluene, xylenes and chlorobenzenes. The reaction is generally carried out in a temperature range from approximately 13()C to 160C. Where appropriate the reaction is in addition carried out in the presence of a basic catalyst, e.g. a higher-boiling amine ~see, for example, Helv. Chim. Acta 11, 779 (1928) and US Patent Specification No. 2 416 738] or pyridine.

The subsequent reaction of the compound of formula XV, XVII or XVIII prepared in that manner with the carbamic acid lower alkyl ester of formula XIX is advantageously carried out in a substantially anhydrous diluent and in the presence of an acidic catalyst at elevated temperature. Suitable diluents are especially organic solvents that form azeotropes with water, such as aromatic compounds, e.g. benzene, toluene and xylenes;
cyclic aliphatic compounds, such as cyclohexane; and halogenated hydrocarbons, such as carbon tetrachloride and chlorobenzene, and suitable acidic catalysts are especially strong mineral acids, such as sulfuric acid; organic acids, such as orthophosphoric acid and polyphosphoric acid; and acidic cation exchangers, such as "Amberlyst 15" (Fluka). The reaction is generally carried out in a temperature range from approximately 70C to 150C, preferably at the reflux temperature of the reaction mixture. Under those reaction conditions the desired rapid removal of the water formed during the reaction is achieved.

The starting marterials of formula IV, the corresponding enol ethers and their preparation are for the most part described in European Patent Publications Nos. 195 346 and 260 621.
Those starting materials IV and enol ethers for which the preparation is not described may be prepared analogously to the known starting materials.

The starting matenals of formula VI used in process variant i) can be prepared by halogenating the corresponding uracil derivative of the above formula I'. The halogenating agent used for the halogenation is especially thionyl chloride, phosphorus pentachloride or phosphorus oxychloride, or phosphorus pentabromide or phosphoryl bromide. If desired a mixture of phosphorus pentachloride and phosphorus oxychloride, or of phosphoruspenta~romide and phosphoryl bromide, may be used, it being possible for excess 2~ d phosphorus oxychloride or phosphoryl bromide, respectively, to act as diluent. The chlorination or bromination can be carried out in the presence of an inert diluent, especially an aprotic organic solvent, such as an aliphatic or aromatic hydrocarbon, e.g.
n-hexane, benzene, toluene or a xylene; a halogenated aliphatic hydrocarbon, e.g.
methylene chloride, chloroform or 1,2-dichloroethane; a halogenated aromatic hydrocarbon, e.g. chlorobenzene, or a tertiary amine, e.g. N,N-dimethylaniline, but this is not necessary if phosphorus oxychloride or phosphoryl bromide is used as halogenating agent. If the halogenating agent used is thionyl chloride it has proved advantageous to add a catalytic amount of dimethylformamide. The reaction temperatures generally range from 0C to the reflux temperature of the reaction mixture, preferably from 80C to 120C.

The uracil derivatives of formulae I', I", I" ', I" " and I" " ' and enol ethers used as starting materials in process variants c), e), f), g) and h) are sub-groups of compounds of formula I
and the enol ethers thereof. The remaining starting mate~ials and reagents involved in the process variants and in the reaction schemes are either known or can be prepared by methods that are known ~ se.

The compounds of formula I and their enol ethers and salts (referred to in the following collectively as "compounds of the invention" or "active ingredients") are suitable for controlling, preventing or eliminating plant growth, especially undesired plant growth.
The compounds of the invention possess especially herbicidal propeIties and are suitable for controlling weeds, including grass weeds, for example Abutilon theophrasti, Amaranthus retroflexus, Agropyron repens, Alopecurus myosuroides, Avena fatua, Bromus inermis, Cyperus esculentus, Ipomoea purpurea, Poa annua, Sorghum halepense, Stellaria media, Cassia obtusifolia, Chenopodium album, Chrysanthemum segetum, Datura strarnonium, Digitana sanguinalis, Echinochloa crus-galli, Galium apanne,Matricaria chamomilla, Setaria faberii, Sinapis arvensis and Xanthium pennsylvanicum, in diverse crops of useful plants, for example rape, soybean, Gotton, rice, wheat and maize crops, but especially in cotton crops. In addition, the compounds are both preemergence and postemergence herbicides. Furtherrnore, the compounds of the invention can be used to control undesired plant growthf e.g. in potatoes, cotton plants, sunflowers~ seed vegetables and water weeds. They may be used, for example, as burning-off agents to facilitate the harvesting of potatoes and cotton.

In practice, usually a concentration of 0.5 to 6.0 kg of the compound of the invenLion/ha, - 22 - ~35~

preferably 1 g to 200 g of the compound of the invention/ha, is sufficient to achieve the desired herbicidal effect.

The concentration required for the desired effect can be determined by tests. It is dependent on the nature of the action, the stage of development of the cultivated plant and of the weed and on the application (place, time, method) and can vary widely as a function of those parameters.

The weed control composition according to the invention is characterised in that it comprises an effective amount of at least one compound of formula I, as defined above, or of an enol ether or salt thereof, together with formulation adjuvants. The composition advantageously comprises at least one of the following formulation adjuvants: solid carriers; solvents or dispersants; surfactants (wetting agents and emulsifiers3; dispersants (without surface-active action); and stabilisers. Using those and other adjuvants, those compounds, that is to say the herbicidal active ingredients, can be converted into customary formulations, such as dusts, powders, granules, solutions, emulsions, suspensions, emulsifiable concentrates, pastes and the like.

The compounds of formula I and their enol ethers are in general water-insoluble, whereas the salts, especially the aL~cali metal salts and arnmonium salts, are generally water-soluble; they can be formulated according to the methods customary for water-insoluble and water-soluble compounds using the appropriate formulation adjuvants. The preparation of the compositions can be carried out in a manner known E~ se, e.g. by mixing the active ingredient in question with solid carriers, by dissolving or suspending in suitable solvents or dispersants, optionally using surfactants as wetting agents or emulsifiers and/or dispersants, by diluting ready-prepared emulsi~lable concentrates with solvents or dispersants etc..

Suitable solid carriers are essentially natural mineral substances, such as chalk, dolomite, limestone, argillaceous earths and silicic acid and salts thereof (for example diatomaceous earth, kaolin, bentonite, talcum, attapulgite and montmorillonite); synthetic mineral substances, such as highly dispersed silicic acid, aluminium oxide and silicates; organic materials, such as cellulose, starch, urea and synthetic resins; and fertilisers, such as phosphates and nitrates, it being possible for such caIriers to be, ~or exarnple, in the form of po~vders or granules.

- 23 ~ 9 9J

Suitable solvents and dispersants are essentially aromatic compounds, such as benzene, toluene, xylenes and alkylnaphthalenes; chlorinated aromatic compounds and chlorinated aliphatic hydrocarbons, such as chlorobenzenes, chloroethylenes and methylene chloride;
aliphatic hydrocarbons, such as cyclohexane and paraffins, e.g. petroleum fractions;
alcohols, such as butanol and glycol, and the* ethers and esters; ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; and strongly polar solvents or dispersants, such as dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide, such solvents preferably having flash points of at least 30C and boiling points of at least 50C, and water. Also suitable as solvents and dispersants are so-called liquefied gaseous extenders or carriers, which are products that are gaseous at room temperature under normal pressure. Examples of such products are especially aerosol propellant gascs, such as hydrocarbons, e.g. propane and isobutane, and halogenated hydrocarbons, e.g. dichlorodifluoromethane. If the weed control composition of the invention is in the form of a pressurised gas pack, then advantageously a solvent is used in addition to the propellant gas.

The surfactants (wetting agents and emulsifiers) may be non-ionic compounds, such as condensation products of fatty acids, fatty alcohols or fat-substituted phenols with ethylene oxide; fatty acid esters and ethers of sugars or of polyhydnc alcohols; the products obtained from sugars or polyhydric alcohols by condensation with ethylene oxide; block polymers of ethylene oxide and propylene oxide; or alkyldimethylamine oxides.

The surfactants may also be anionic compounds, such as soaps; fatty sulfate esters, e.g.
dodecyl sodium sulfate, octadecyl sodium sulfate and cetyl sodium sulfate; alkyl-sulfonates, arylsulfonates and fatty aromatic sulfonates, such as alkylbenzene sulfonates, e.g. calcium dodecylbenzene sulfonate, and butylnaph~halene sulfonates; and morecomplex fatty sulfonates, e.g. the amide condensation products of oleic acid andN-methyltaurin, and the sodium sulfonate of dioctyl succinate.

Finally, the surfactants may be cationic compounds~ such as aL~cyldimethylbenzyl-ammonium chlorides, diaL~yldimethylammonium chlorides, aL~cyltrimethylammonium chlorides and ethoxylated quaternary ammonium chlorides.

Suitable dispersants (without surface-active action) are essentially lignin, sodium and ammonium salts of lignosulfonic acids, sodium salts of maleic acid anhydride/di-isobutylene copolymers, sodium and ammonium salts of sulfonated polycondensationproducts of naphthalene and formaldehyde, and sulfite waste liquors.

As dispersants, which are suitable especially as thickeners and anti-settling agents, there may be used, e.g., methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, alginates, caseinates and blood albumin.

Examples of suitable stabilisers are acid-binding agents, e.g. epichlorohydrin, phenylglycidyl ethers and soya epoxides; antioxidants, e.~. gallic acid esters and bu~yl-hydroxytoluene; UV absorbers, e.g. substituted benzophenones, diphenylacrylonitrile acid esters and cinnamic acid esters; and deactivators, e.g. salts of ethylenediaminetetraacetic acid and polyglycols.

The weed control compositions according to the invention may comprise, in addition to the active ingredients of the invention, synergists and other active ingredients, e.g.
insecticides, acaricides, fungicides, plant-growth regulators and fertilisers. Such combination compositions are suitable for strengthening the activity or broadening the activity spectrum.

The weed control compositions accordin~ to the invention generally comprise from 0.01 to 95 % by weight, preferably from 0.5 to 75 % by weight, of one or more compounds according to the invention as active ingredient(s). They may, for example, be in a form that is suitable for storage and transport. In such formulations, e.g. emulsifiable concentrates, the active ingredient concentration is normally in the higher range, preferably from 1 to 50 % by weight, especially from 10 to 20 % by weight. Thoseformulations can then be diluted, e.g. with identical or different inert substances, to the active ingredient concentrations suitable for practical use, that is to say preferably approximately 0.01 to 10 % by weight, especially approximately 0.0()5 to 5 % by weight.
The active ingredient concentrations may, however, also be lower or higher.

As mentioned above, the preparation of the weed control compositions according to the invention can be carried out in a manner known ~ se.

In order to prepare pulverulene compositions, the active ingredient, that is to say at least one compound of the invention, may be mixed with a solid carrier, e.g. by grinding together; or the solid caTrier may be impregnated with a solution or suspension of the active ingredient and then the solvent or dispersant, as the case may be, removed by evaporation, heating or filtering with suction under reduced pressure. Such pulverulent compositions can be made readily wettable with water by adding surfactants or dispersants, so that they can be converted into aqueous sllspensions that are suitable, e.g., as spray compositions.

The active ingredient may also be mixed with a surfactant and a solid carrier to form a wettable powder that is dispersible in water, or may be mixed with a solid pregranulated carrier to form a granular product.

If desired, the active ingredient may be dissolved in a water-immiscible solvent, such as, for example, a high-boiling hydrocarbon, that advantageously comprises dissolvedemulsifier so that the solution is self-emulsifying when water is added. Alternatively, the active ingredient may be mixed with an emulsifier and the mixture then diluted with water to the desired concentration. Further, the active ingredient may be dissolved in a solvent and then mixed with an emulsifier. Such a mixture may also be diluted with water to the desired concentration. Emulsifiable concentrates and ready-for-use emulsions are obtained in this manner.

The use of the weed control compositions according to the invention, to which the present invention also relates, may be in accordance with customary application methods, such as sprinkling, spraying, dusting, pouring or scattering. The method according to the invention of controlling weeds comprises treating the substrates to be protected against weeds and/or the weeds with a compound of the invention or with a weed control composition of the invention.

The following Exarnples are to illustrate the invention further.

I. Preparation of the compounds of forrnula I:

Example 1: A mixture of 50.0 g of 2-chloro-5-~3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyIimidinyl]-4-fluorobenzoic acid isopropyl ester and 25.4 g of copper(I) cyanide in 225 ml of dimethyl-3,4,5,6-te~rahydro-2(1H)-pyrimidinone is heated for 2.5 hours at 195C under nitrogen. The mixture is then cooled to room temperature and 21 of ethyl acetate are added. The mixture is then poured onto 1.31 of water and 300 ml of 32% hydrochloric acid, and the whole is sti~d for 45 minutes at 2~

room temperature until two distinct layers have formed. The organic phase is removed, washed twice with 200 ml of water each time and dried over anhydrous sodium sulfate.
Concentration by evaporation of the organic solution yields crystalline 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo- 1 (2H)-pyrimidinyl]-4-fluorobenzoic acid isopropyl ester, m.p. 188-200C.

Examples 2-10: The compounds of formula I listed in the following Table 1 are obtained analogously to the process described in Example 1 by treating the corresponding uracil derivative of formula IV with copper(I) cyanide:

R5~ N ~O
N ~XCOOR2 o R3 CN

Exa- Rl R2 R3 R4Rs Physical mple data 2 CH3 CH(CH3)2 H HCF3 m.p. 125-127C
3 CH3 CH(CH3)2 F HCF3 m.p. 130-132C
4 CH3 CH(CH3)2 F HC2Fs m.p. 116-118C
S CH3 CH(C~I3)2 F -(CH2)4- m.p. 170-172C
6 CH3 CH(C~I3)2 F -(CH2)3- m.p. 164-166C
7 CH3 CH(CH3)2 F F¦ CF3 m.p. 133-136C

8 CH3 CH3 H H¦ CF3 m.p. 167-168C
9 CHF2 CH(CH3)2 F -(CH2)4- m.p. 142-145C
CHF2 CH(CH3)2 F H ¦ CH3 m.p. 146- 148C

Example 11 A solution of 30.5 g of 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-fluorobenzoic acid isopropyl ester (see Example 1) in 150 ml of methanol is maintained at 1-3C for 15 minutes with 4.0 g of sodium hydroxide in 5û
ml of water and then stirred for 23 hours. I'he solution is substantially concentrated by evaporation under reduced pressure and the residue is adjusted to a pH value of 2 with 2N

- 27 ;~

hydrochloric acid. The resulting precipitate is filtered off with suction and subsequently washed with n-hexane to yield 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-~luorobenzoic acid, m.p. 232C (with decomposition).

Example 12 A solution of 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1~2H)-pyrimidinyl~-4-fluorobenzoic acid ~see Example 9) in 30 ml of absolute dimethylformamide is stirred for 2 hours at room temperature with 0.29 g of a 55%
sodium hydride dispersion. A solution of 1.1 g of propargyl bromide in 10 ml of absolute dimethylformamide is then added dropwise over a period of 10 minutes and the reaction mixture is subsequently stirred for 3 hours.

The mixture is then dissolved in 100 ml of ethyl acetate, the solution is washed thoroughly with water, and the organic phase is dried over anhydrous sodium sulfate and concentrated to dryness by evaporation under reduced pressure. The residue is purified by chromatography on a silica gel column using n-hexane/ethyl acetate (3:7) as eluant to yield 2-cyano-S - [3 ,6-dihydro-3 ,4-dimethyl-2,6-dioxo- 1 (2H) -pyrimidinyl]-4-fluorobenzoic acid propargyl ester, m.p. 174-177C.

Examples 13-15 Analogously to the process describèd in Exarnple 12, the compounds of formula I listed in the following Table 2 are obtained by esterifying 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2~)-pyrimidinyl]-4-fluorobenzoic acid (see Example 11) with allyl bromide, methyl iodide and 2-methoxyethyl bromide, respectively:

CH3 ~N~O
~ N~ COOR2 2~5F~
.

Table 2 Example R2 Physical data 13 allyl m.p. 143-148C
14 methyl m.p. 244-246C
2-methoxyethyl m.p. 126-130C

Example 16 A mixture of 3.0 g of finely pulverised 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-fluorobenzoic acid, 30 ml of freshly distilled thionyl chloride and 3 drops of dimethylfolrnamide is heated at reflux temperature for 1 hour with stirring, after which a clear solution has fonned. The mixture is then concentrated to dryness by evaporation to yield 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-fluorobenzoic acid chloride, m.p. 160C, which is used, unpurified, as the starting material in the next reaction step.

A solution of l.S g of 1,2,3,6-tetrahydrobenzyl alcohol and 0.015 g of 4-dimethylaminopyIidine in 2.5 g of pyridine is added dropwise, at room temperature, to a solution of 3.8 g of 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-fluorobenzoic acid chloride in 130 ml of tetrahydrofuran. After heating the reaction mixture for 12 hours at 60C, the resulting suspension is substantially concenlrated by evaporation under reduced pressure and the residue is dissolved in ethyl acetate.

The organic solution is washed thoroughly with water, the organic phase is dried over anhydrous sodium sulfate and concentrated to dryness by evaporation under reduced pressure, and the residue is puri~1ed by chromatography on a silica gel column using n-hexane/ethyl acetate (3:7) as eluant to yield 2-cyano-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyll-4-fluorobenzoic acid 1,2,3,6-tetrahydrobenzyl ester, mass spectrum (m/e): 397(15)M~.

Biolo~ical Fxamples Example B 1: Preemer~ence herbicidal action Immediately after sowing the test plants (a number of weeds, both monocotyledonous and - ' . :

' :

dicotyledonous) in seed trays in the greenhouse, an aqueous spray mixture, colTesponding to a rate of application of 3 kg of active ingredient~ectare, is used to treat the soil surface.

The test compounds are preferably formulated as emulsifiable concen~ates (EC) and diluted with water to the desired concentration immed;ately before application. Insoluble compounds are forrnulated as wettable powders (WP) using kaolin as inert carrier. The wettable powder is suspended in water immediately before application.

The concentrations of active ingredient in g/ha refer to the soil surface in the containers unless indicated otherwise. The spraying volume is lOOO l/ha (coIresponding to 100 mVm2).

The plant seeds are sown in plastics plant pots of various sizes containing heat-sterilised (steam-treated) soil (agricul~lral soil 2.6% peat,20% clay,30% silt,47% sand). The plants are kept in the greenhouse at average tenmperature (17 - 25C in winter,18 - 35C in summer) (humidity 30 - 90%). The length of the photoperiod is 13 to 16 hours/day and i~, if necessary, supplemented by artificial light (15000 to 180001ux). The artificial lighting is also automatically activated if the intensity of the daylight is inadequate.

After 3 weeks the herbicidal action is evaluated by cQmparison with an untreated control group using an eleven-stage linear evaluation scheme (necrosis, chlorosis, reduction, deformation) (2 = 80-100% damage, l = 30-79% damage,0 - 0-29% damage) Table Bl: preemer~ence herbicidal action:

Example S E A A C S A D M C
O ~ V L H T B A A A
R H E O E E U T T S
G I N P N L TU R S
-01 2222 ~ 22222 02 22 ~ 2222222 0~ 2222222222 13 222222 ~ 222 - Key to the Table:
SORG Sorghum halopense ECHI Echinochloa crus-galli AVEN Avena fatua ALOP Alopecurus myosuroides CHEN Chenopodium album STEL Stellaria media ABUT Abutilon theophrasti MATR MatricaTia chamomilla CASS Cassia media Example B2: Postemer ence helbicidal action (contact herbicide) A number of weeds, both monocotyledonous and dicotyledonous, are treatèd postemergence (at the 2- to 6-leaf stage) with an aqueous active ingredient dispersion at a rate of 3 kg of active ingredient per hectare.

The test compounds are preferably formulated as emulsifiable concentrates ~EC) and diluted with water to the desired concentration immediately before applica~ion. Insoluble compounds are formulated as wettable powders (~1P) using kaolin as inert calTier. The wettable powder is suspended in water immediately before application.

The concentrations of active ingredient in g~a refer to the soil surface in the containers unless indicated otherwise. The spraying volume is 500 l~a.

The plant seeds are sown in plastics plant pots of vaTious sizes containing heat-sterilised (steam-treated) soil ('Optima' soil 80% peat,20% loess). The plants are kept in the greenhouse at average temperature (17 - 25C in winter, l8 - 35C in summer) (atmospheric humidity 30 - 90%). The length of the photoperiod is 13 to 16 hours/day and is, if neCeSSaTy, supplemented by ar~ficial light (150û0 to 180û0 lux). The artificial lighting is also automatically activated if the intensity of the daylight is inadequate.

After 3 weeks the herbicidal action is evaluated by compaIison with an untreated control group using an eleven-stage linear evaluation scheme (necrosis, chlorosis, reduction, deformation) (2 = 80-100% damage, l = 30-79% damage,0 = 0-29% damage).

31 ~ r.~

Table B2: postemer~ence herbicidal action:

Example S E A A C S A D M C
O C V L H T B A A A
R H E O E E U T T S
G I N P N L T U E~ S

07 222 ~ 222222 ~. .

Formulation examples of active substances of the formula I
(% = percent bY wei~ht) 1. Wettablepowder a) b) c) Active subst. from Exarnples 1-15 20 % 50 % 0.5 %
Naligninsulfonate 5 % 5 % 5 %
Na lauryl sulfate 3 % - -Na diisobutylnaphthalenesulfonate - 6 % 6 %
Octylphenol polyethylene glycol ether (7-8 mol of EO) - 2 % 2 %
Highly-disperse silica 5 % 27 % 27 %
Kaolin 67 %
Sodium chloride - - 59.5 %

The active substance is thoroughly mixed with the additives and thoroughly ground in a suitable mill. This gives wettable powders which can be diluted with water to give suspensions of any desired concentration.

2.Emulsion concentrates a) b) Active subst. from Exarnples 1-15 10 % 1 %
Ca dodecylbenzenesulfonate 3 % 3 %
Octylphenol polyethylene glycol ether (4-5 mol of EO) 3 % 3 %
Castor oil polyethylene glycol ether (36 mol of EO) 4 % 4 %
Cyclohexanone 30 % 10 %
Xylene mixture 50 % 79 %

Emulsions of any desired concentration can be prepared ~rom such concen~ates by diluting thern with water.

3.Dusts a) b) Active subst. from Examples 1-15 0.1 % 1 %
Talc 99-9 %
Kaolin 99 %

- 33 - ;2~

Ready-to-use dusts are obtained by intimately mixing the calTier with the active substance.

4. Extrudergranules a) b) Active subst. from Examples 1-15 10 % 1 %
Na ligninsulfonate 2 % 2 %
Carboxymethylcellulose 1% 1%
Kaolin 87 % 96 %

The active substance is mixed with the additives, and ehe mixture is ground and moistened with water. This mixture is extruded and subsequently dried in a stream of air.

5. Coated granules Active subst. from Examples 1-15 3 %
Polyethylene glycol (MW 200) 3 %
Kaolin 94 %

The kaolin is moistened with polyethylene glycol and the fimely-gTound active substance is applied uniformly thereto in a mixer. Dust-free coated granules are obtained in this manner.

6. Suspensionconcentrate a) Active subst. from Examples 1-15 5 % 40 %
Ethylene glycol 10 % 10 %
Nonylphenol polyethylene glycol ether (15 mol of EO) 1 % 6 %
Na ligninsulfonate 5 % 10 %
Carboxymethylcellulose 1% 1%
37 % aqueous formaldehyde solution 0.2 % 0.2 %
Silicone oil in the form of a 75% aqueous emulsion 0.8 % 0.8 %
Water - 77 % 3~%

The ~mely-ground active substance is mixed intimately with the additives. This gives a suspension concentrate, from which suspensions of any desired concen~ation can be prepared by dilu~ing it with water.

- 34 ~
.

7. Salt solution Active subst. from Examples 1-15 5 %
Isopropylamine 1 %
Octylphenol polyethylene glycol ether (78 mol of EO) 3 %
Water 91%

The compounds of the formula I are employed as such or preferably as compositions together with the auxiliaries customary in formulation technology, and they are therefore processed in a known manner to give, for example, emulsion concentrates, directly sprayable or dilutable solutions, dilute emulsions, sprayable powders, soluble powders, dusts, granules, and also encapsulations, for example in polymeric substances. The application methods, such as spraying, atomising, dusting, scattering or pouring, as well as the type of compositions are selected to suit the intended aims and the preYailing circumstances.

Claims (11)

1. A compound of the general formula I

wherein R1 is hydrogen, C1-C4alkyl, C3-C4alkenyl, C3-C4alkynyl, C2-C6alkoxyalkyl or C1-C4haloalkyl, R2 is hydrogen, C1-C6alkyl, C2-C6alkoxyalkyl, C4-C7cycloalkenyl-C1-C4alkyl that is unsubstituted or ring-substituted by from 1 to 3 C1-C3alkyl groups, C3-C4alkenyl, C4-C7cycloalkenyl-C3-C5alkenyl that is unsubstituted or ring- substituted by from 1 to 3 C1-C3alkyl groups, aryl-C3-C5alkenyl, C3-C4alkynyl, C4-C7cycloalkenyl-C3-C5alkynyl that is unsubstituted or ring-substituted by from 1 to 3 C1-C3alkyl groups, or aryl-C3-C5-alkynyl, R3 is hydrogen or halogen, R4 is hydrogen, halogen or C1-C4alkyl and R5 is C1-C4alkyl or C1-C4haloalkyl, or R4 and R5 together are tri- or tetra-methylene, with the proviso that, when R5 is C1-C4haloalkyl, R1 is other than C1-C4haloalkyl and R2 is other than hydrogen, or the corresponding enol ether of such a compound of formula I wherein R1 is other than hydrogen or C1-C4haloalkyl, or a salt of such a compound of formula I wherein R1 and/or R2 are/is hydrogen.

2. A compound according to claim 1, wherein R1 is C1-C4alkyl.

3. A compound according to claim 1 or 2, wherein R2 is C1-C6alkyl, C2-C6alkoxyalkyl, C3-C4alkenyl or C3-C4alkynyl.

4. A compound according to any one of claims 1 to 3, wherein R3 is hydrogen or fluorine.

5. A compound according to any one of claims 1 to 4, wherein R4 is hydrogen or fluorine and R5 is C1-C4alkyl or trifluoromethyl, or R4 and R5 together are tri- oder tetra-methylene.

6. A compound according to claim 1, selected from 2-cyano-5-(1,2,4,5,6,7-hexahydro-1-methyl-2,4-dioxo-3H-cyclopenta[d]pyrimidin-3-yl)-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-(1,2,4,5,6,7-hexahydro-1-methyl-2,4-dioxo-3H-cyclopenta[d]-pyrimidin-3-yl)-benzoic acid isopropyl ester, 2-cyano-5-[1,4,5,6,7,8-hexahydro-1-methyl-2,4-dioxo-3(2H)-quinazolinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[1,4,5,6,7,8-hexahydro-1-methyl-2,4-dioxo-3(2H)-quinazolinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid `
isopropyl ester, 2-cyano-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid isopropyl ester and 2-cyano-5-[3 ,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-fluorobenzoic acid isopropyl ester.

7. A weed control composition which comprises an effective amount of at least one compound of the general formula I
wherein R1 is hydrogen, C1-C4alkyl, C3-C4alkenyl, C3-C4alkynyl, C2-C6alkoxyalkyl or C1-C4haloalkyl, R2 is hydrogen, C1-C6alkyl, C2-C6alkoxyalkyl, C4-C7cycloalkenyl-C1-C4alkyl that is unsubstituted or ring-substituted by from 1 to 3 C1-C3alkyl groups, C3-C4alkenyl, C4-C7cycloalkenyl-C3-C5alkenyl that is unsubstituted or ring- substituted by from 1 to 3 C1-C3alkyl groups, aryl-C3-C5alkcenyl, C3-C4alkynyl, C4-C7cycloalkenyl-C3-C5alkynyl that is unsubstituted or ring-substituted by from 1 to 3 C1-C3alkyl groups, or aryl-C3-C5-alkynyl, R3 is hydrogen or halogen, R4 is hydrogen, halogen or C1-C4alkyl and R5 is C1-C4alkyl or C1-C4haloalkyl, or R4 and R5 together are tri- or tetra-methylene, with the proviso that, when R5 is C1-C4haloalkyl, R1 is other than C1-C4haloalkyl and R2 is other than hydrogen, or of the enol ether of such a compound I wherein R1 is other than hydrogen or C1-C4halo-alkyl, or of a salt of such a compound wherein R1 and/or R2 are (is) hydrogen, and formulation adjuvants.

8. A weed control composition according to claim 7, which comprises an effective amount of at least one compound selected from the group 2-cyano-5-(1 ,2,4,5,6,7-hexahydro-1-methyl-2,4-dioxo-3H-cyclopenta[d]pyrimidin-3-yl)-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-(1,2,4,5,6,7-hexahydro-1-methyl-2,4-dioxo-3H-cyclopenta[d]-pyrimidin-3-yl)-benzoic acid isopropyl ester, 2-cyano-5-[1,4,5,6,7,8-hexahydro-1-methyl-2,4-dioxo-3(2H)-quinazolinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[1,4,5,6,7,8-hexahydro-1-methyl-2,4-dioxo-3(2H)-quinazolinyl]-benzoic acid isopropyl ester, 2-cyano-4-fluoro-5-[3,6-dihydro-3,4-dimethyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid isopropyl ester, 2-cyano-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-1(2H)-pyrimidinyl]-benzoic acid isopropyl ester and 2-cyano-5-[3,6-dihydro-3-methyl-4-trifluoromethyl-2,6-dioxo-1(2H)-pyrimidinyl]-4-fluorobenzoic acid isopropyl ester, and formulation adjuvants.

9. A process for the preparation of compounds of the general formula I
wherein R1 is hydrogen, C1-C4alkyl, C3-C4alkenyl, C3-C4alkynyl, C2-C6alkoxyalkyl or C1-C4haloalkyl, R2 is hydrogen, C1-C6alkyl, C2-C6alkoxyalkyl, C4-C7cycloalkenyl-C1-C4alkyl that is unsubstituted or ring-substituted by from 1 to 3 C1-C3alkyl groups, C3-C4alkenyl, C4-C7cycloalkenyl-C3-C5alkenyl that is unsubstituted or ring- substituted by from 1 to 3 C1-C3alkyl groups, aryl-C3-C5alkenyl, C3-C4alkynyl, C4-C7cycloalkenyl-C3-C5alkynyl that is unsubstituted or ring-substituted by from 1 to 3 C1-C3alkyl groups, or aryl-C3-C5-alkynyl, R3 is hydrogen or halogen, R4 is hydrogen, halogen or C1-C4alkyl and R5 is C1-C4alkyl or C1-C4haloalkyl, or R4 and R5 together are tri- or tetra-methylene, with the proviso that, when R5 is C1-C4haloalkyl, R1 is other than C1-C4haloalkyl and R2 is other than hydrogen, and of the enol ethers of those compounds of formula I wherein R1 is other than hydrogen or C1-C4haloalkyl, and salts of those compounds of formula I wherein R1 and/or R2 (are) is hydrogen, which comprises a) for the preparation of those compounds of formula I wherein R1 is hydrogen and R2 is other than hydrogen and R4 is other than chlorine, bromine or iodine and, if desired, metal salts of those compounds, subjecting to cyclisation, under basic conditions, a compound of the general formula II

wherein R3 and R5 are as defined above, R2' has the meaning given above for R2 with the exception of hydrogen, R4' is hydrogen, fluorine or C1-C4alkyl or, together with R5, is tri-or tetra-methylene, and R6 is lower alkyl, and, if desired, converting a possibly resulting metal salt form of the uracil derivative into the corresponding acid form (R1 = hydrogen) by treatment with an acid, b) for the preparation of those compounds of formula I wherein R1 is hydrogen and R2 is other than hydrogen, R4 is other than chlorine, bromine or iodine and R5 is other than C1-C4haloalkyl and, if desired, metal salts of those compounds, subjecting to cyclisation, under basic conditions, a compound of the general formula III

wherein R2' and R3 are as defined above, R4' is hydrogen, fluorine or C1-C4alkyl or, together with R5', is tri- or tetra-methylene, R5' is C1-C4alkyl or, together with R4', is tri-or tetra-methylene, and R7 is lower alkyl, and, if desired, converting a possibly resulting metal salt of the uracil derivative of formula I into the acid form (R1 = hydrogen) by treatment with an acid, c) for the preparation of those compounds of formula I wherein R1 is C1-C4alkyl,C3-C4alkenyl, C3-C4alkynyl, C2-C6alkoxyalkyl or C1-C4haloalkyl, subjecting a uracil derivative of the general formula I

wherein R2, R3, R4 and R5 are as defined above, to alkylation with a corresponding alkylating agent comprising a C1-C4alkyl, C3-C4-alkenyl, C3-C4alkynyl, C2-C6alkoxyalkyl or C1-C4haloalkyl group, d) for the preparation of all compounds of formula I and the enol ethers, treating a uracil derivative of the general formula IV

wherein Hal1 is halogen, preferably chlorine or bromine, and R1,R2,R3,R4 and R5 are as defined above, or the corresponding enol ether, with a metal cyanide, e) for the preparation of those compounds of formula I wherein R2 is hydrogen and R5 is other than C1-C4haloalkyl, and the enol ethers thereof, hydrolysing a benzoic acid ester of the general formula I"

wherein R1, R2', R3, R4 and R5' are as defined above, to form the corresponding benzoic acid, f) for the preparation of those compounds of forrnula I wherein R1 and R2 are each other than hydrogen and R5 is other than C1-C4haloalkyl, and the corresponding enol ethers, esterifying a benzoic acid of the general formula I''' wherein R1" is C1-C4alkyl, C3-C4alkenyl, C3-C4alkynyl, C2-C6alkcoxyalkyl or C1-C4halo-alkyl and R3, R4 and R5' are as defined above, or the corresponding enol ether, it being possible for the benzoic acid or its enol ether to be in the form of a reactive derivative, with a hydroxy compound of the general formula HO-R2' V
wherein R2' is as defined above, or with a reactive derivative of that hydroxy compound, g) for the preparation of those compounds of formula I wherein R1 and R2 are each other than hydrogen, and the enol ethers thereof, subjecting a benzoic acid ester of the general formula I""

wherein R1", R3, R4 and R5 are as defined above and R2" is C1-C6alkyl, C3-C4alkenyl, C3-C4alkynyl or C2-C6alkoxyalkyl, or the corresponding enol ether, to a transesterification reaction with a hydroxy compound of the above formula V, the reagent V having a higher boiling point than the respective alkanol, alkenol or alkynol R2"OH, h) for the preparation of those compounds of formula I wherein R4 is chlorine, bromine or iodine, and the corresponding enol ethers, chlorinating, brominating or iodinating a uracil derivative of the general formula I''''' wherein R1, R2, R3 and R5 are as defined above, or the corresponding enol ether, i) for the preparation of the enol ethers of the compounds of formula I, treating a uracil derivative of the general formula VI

wherein R2, R3, R4 and R5 are as defined above, and Hal2 is chlorine or bromine, with an alkanol, alkenol or alkynol R1'OH in the presence of an organic base, or with the corresponding alcoholate, alkenolate or alkynolate, respectively, of the general formula R1O?M? VII

wherein R1' is as defined above and M? is an equivalent of a metal ion, and, if desired, converting a resulting compound of formula I wherein R1 and/or R2 are (is) hydrogen into a salt.

10. A method of controlling weeds which comprises treating the substrates to be protected against weeds and/or the weeds with an effective amount of a compound according to any one of claims 1 to 6 or of a composition according to claim 7 or 8.

11. The use of a compound according to any one of claims 1 to 6, or of a composition according to either claim 7 or claim 8, to control weeds.